Dear Editor,We present the reported case of repetitive bilateral suprachoroidal expulsive hemorrhage(SEH)after anti-glaucoma surgeries.SEH is a rare but potentially devastating complication of intraocular surgery.Long...Dear Editor,We present the reported case of repetitive bilateral suprachoroidal expulsive hemorrhage(SEH)after anti-glaucoma surgeries.SEH is a rare but potentially devastating complication of intraocular surgery.Long-term ocular hypertension,high myopia,older age,arterial sclerosis,and aphakia have been reported as preoperative risk factors for developing SEH^([1]).The prognosis for the visual acuity is poor without proper management.A suggested time for surgical drainage is said to be 10-14d when the hemorrhagic clot begins to liquefy^([2]).展开更多
Introduction: One of the most common disorders of the urinary tract is Urolithiasis. Twenty percent of lithiasis are located in the ureter of which 68% are seen in the distal ureter. The concept of medical expulsive t...Introduction: One of the most common disorders of the urinary tract is Urolithiasis. Twenty percent of lithiasis are located in the ureter of which 68% are seen in the distal ureter. The concept of medical expulsive therapy (MET) has been developed with enough knowledge of the ureter physiology in order to make easier the spontaneous expulsion of the stone. The aim of this study was to evaluate the efficacy and safety of three different drugs for the treatment of pelvic ureteral stones. Materiel and Methods: Between October 2017 and November 2018, 90 adult patients presenting with low or non-obstructive pelvic ureteral stones sized 8 to 10 mm were included. They were prospectively randomized, using computer-based randomization charts, into three equal groups: treatment with ketoprofen 100 mg once daily (Group I), silodosin 8 mg once daily (Group II) and tadalafil 5 mg once daily (Group III). The aim was to compare spontaneous expulsion of stone between those drugs Results: The mean expulsion time from the start of MET was 11.5 ± 3.27 days for ketoprofen group, 10.71 ± 3.98 days for silodosin group and 10.57 ± 3.40 days for tadalafil group. But these differences were also not significant (P = 0.79). The use of analgesics (grade II) was higher in groups II and III compared to group I, but without significant difference (23.33% in group I, 33.33% in group II and 40% in group III, p = 0.38). Discussion: The overall chance of spontaneous passage is low when the stone diameter is sized more than 7 mm. A wide range of spontaneous passage rates have been reported in the literature, varying from 71% to 98% for distal ureteral stones less than 5 mm and 25% - 53% for stone sized 5 to 10 mm with a mean expulsion time of more than 10 days. Conclusion: The three drugs have a low expulsion rate for 8, 9 and 10 mm pelvic ureteral stones with a higher adverse event rate for the NSAID group.展开更多
Objective: To review the evidence for tamsulosin as medical expulsive therapy in enhancing the effectiveness of distal ureteral stone clearance rate. Methods: We searched Pubmed/Medline, Embase, CBM and the Cochrane L...Objective: To review the evidence for tamsulosin as medical expulsive therapy in enhancing the effectiveness of distal ureteral stone clearance rate. Methods: We searched Pubmed/Medline, Embase, CBM and the Cochrane Library up to October 2011. All randomized controlled trials in which tamsulosin was evaluated with distal ureterolithiasis were eligible for the analysis. Outcome measure assessed was stone clearance rate. Two authors independently assessed study quality and extracted data. All data were analyzed using RevMan 5.1. Results: Thirteen studies involving 1067 participants met the inclusion criteria. Study duration ranged from 7 to 42 d. The pooled analysis showed an improvement of 41% in stone clearance rate of tamsulosin as medical expulsive therapy for distal ureteral calculi (RR=1.41, 95% CI=1.18 to 1.70). According to stone size (6 mm<size<10 mm, 5 mm<size<6 mm, size <5 mm), the pooling effects of tamsulosin were analyzed, with a higher stone expulsion rate obtained than control (RR=1.52, 1.75, 1.05, 95% CI=1.30 to 1.77, 1.25 to 2.45, 0.95 to 1.16, respectively). Adverse effects of tamsulosin, mainly retrograde ejaculation, dizziness and hypotension, were reported in 7 included trials. Conclusion: Treatment with tamsulosin appears to be a safe and effective medical expulsion therapy for distal ureterolithiasis. To make a definite clinical recommendation to use tamsulosin as medical expulsive treatment for distal ureteral calculi, high quality multicentric, randomized, double blinded, controlled trials are necessary to prove its efficacy.展开更多
Objective:Medical expulsive therapy(MET)is a suitable option for facilitating stone expulsion in patients with distal ureteral stones.This meta-analysis was conducted to compare efficacy and safety of monotherapy and ...Objective:Medical expulsive therapy(MET)is a suitable option for facilitating stone expulsion in patients with distal ureteral stones.This meta-analysis was conducted to compare efficacy and safety of monotherapy and combination therapy with tamsulosin,silodosin,and tadalafil on stone expulsion rate(SER)and stone expulsion time(SET),as well as their comparative safety,numbers of colic pain episodes,and need for analgesics.Methods:Randomized controlled trials were retrieved by searching PubMed,Scopus,and Web of Science up to November 27,2023.Hand-searching was also conducted in Google Scholar to find additional records.Papers in English that compared the safety and efficacy of at least two of the above agents in adults with distal ureteral stones≤10 mm were included.Results:In total,27 studies were identified(six studies through database searches and 21 through checking reference lists and hand-searching in Google Scholar).More than half of them(n=15,56%)were conducted in India.The SER significantly improved with silodosin compared with tamsulosin(odds ratio[OR]2.24,p<0.001),whereas the difference in SET was non-significant.Tadalafil achieved a significantly higher SER compared with tamsulosin(OR 1.42,p=0.042)without any difference in SET.Subgroup analysis of 5-and 10-mg doses of tadalafil showed no significant difference in SER or SET.We found no significant difference in need for analgesics(mean difference(MD−53.73,p=0.2)or the mean number of colic episodes(MD−0.42,p=0.060)between tadalafil and tamsulosin.SER or SET was not significantly different between silodosin and tadalafil.Tadalafil plus tamsulosin led to a significantly higher SER(OR 1.87,p<0.001)and SET(MD−2.99,p=0.002)compared with tamsulosin,without any significant difference in adverse effects.Conclusion:Compared with tamsulosin,SER significantly improved with silodosin,tadalafil,and the combination of tadalafil plus tamsulosin.Meanwhile,the difference in SET was only significant between tadalafil plus tamsulosin versus tamsulosin.It appears that tadalafil and silodosin have similar efficacy in SET and SER.All medical expulsive therapies had comparable safety.展开更多
Taking the Lower Permian Fengcheng Formation shale in Mahu Sag of Junggar Basin,NW China,as an example,core observation,test analysis,geological analysis and numerical simulation were applied to identify the shale oil...Taking the Lower Permian Fengcheng Formation shale in Mahu Sag of Junggar Basin,NW China,as an example,core observation,test analysis,geological analysis and numerical simulation were applied to identify the shale oil micro-migration phenomenon.The hydrocarbon micro-migration in shale oil was quantitatively evaluated and verified by a self-created hydrocarbon expulsion potential method,and the petroleum geological significance of shale oil micro-migration evaluation was determined.Results show that significant micro-migration can be recognized between the organic-rich lamina and organic-poor lamina.The organic-rich lamina has strong hydrocarbon generation ability.The heavy components of hydrocarbon preferentially retained by kerogen swelling or adsorption,while the light components of hydrocarbon were migrated and accumulated to the interbedded felsic or carbonate organic-poor laminae as free oil.About 69% of the Fengcheng Formation shale samples in Well MY1 exhibit hydrocarbon charging phenomenon,while 31% of those exhibit hydrocarbon expulsion phenomenon.The reliability of the micro-migration evaluation results was verified by combining the group components based on the geochromatography effect,two-dimension nuclear magnetic resonance analysis,and the geochemical behavior of inorganic manganese elements in the process of hydrocarbon migration.Micro-migration is a bridge connecting the hydrocarbon accumulation elements in shale formations,which reflects the whole process of shale oil generation,expulsion and accumulation,and controls the content and composition of shale oil.The identification and evaluation of shale oil micro-migration will provide new perspectives for dynamically differential enrichment mechanism of shale oil and establishing a“multi-peak model in oil generation”of shale.展开更多
The paleo-temperature(Th)data from fluid inclusions are utilized for thermal history modelling using PetroMod software.Generally,bottom hole temperature(BHT)and vitrinite reflectance(Ro)measurements are widely used in...The paleo-temperature(Th)data from fluid inclusions are utilized for thermal history modelling using PetroMod software.Generally,bottom hole temperature(BHT)and vitrinite reflectance(Ro)measurements are widely used in petroleum system modelling(PSM)in the oil industry for calibration purposes.Th representing the minimum temperature of fluid entrapment estimated from fluid-inclusion study provides extra support to build the thermal models for PSM.Fluid inclusion parameters along with Rock-Eval pyrolysis analysis have been used to predict the maturity of oil in terms of API gravity as well as the maturity of source rocks respectively.Two exploratory wells RV-1(Mumbai Offshore Basin)and KK4C-A-1(Kerala-Konkan Offshore Basin),India were examined and the T_(h)from most of the fluid inclusions of wells RV-1 and KK4C-A-1 fell in the oil window range of 60-140℃suggesting thermal conditions favourable for oil generation in both of the wells.T_(h)of coeval aqueous inclusions along with the Hydrocarbon Fluid inclusions(HCFIs)was used to calibrate PSM.Vital parameters show that source rocks of well RV-1 are mature and that of well KK4C-A-1 are immature.Two sets of PSM are created in terms of generation and expulsion for the dry wells RV-1 and KK4C-A-1 and calibrated each well using fluid inclusion Th and BHT.From the fluid inclusion analysis method,it is evident that hydrocarbon generation happened in both wells and the paleo-temperature indicates that the formations of both wells were subjected to temperatures in the oil window range,even though it was designated as dry wells in the present scenario.The present study highlights the application of fluid inclusion paleo-temperature(Th)during calibration instead of commonly used methods.We could obtain desirable and accurate data output from PSM using T_(h) calibration.展开更多
Over half a million patients present to emergency departments and nearly 3 million patients visit healthcare providers annually due to problems associated with urolithiasis.Despite updated guidelines from the American...Over half a million patients present to emergency departments and nearly 3 million patients visit healthcare providers annually due to problems associated with urolithiasis.Despite updated guidelines from the American Urological Association and European Association of Urology for the evaluation and management of nephrolithiasis,considerable variability still exists regarding treatment for acute symptomatic upper urinary tract stones.Therefore,this article will review the current evaluation and management of acute symptomatic nephrolithiasis.Initial management includes analgesia and antiemetics.Additionally,a urinalysis and creatinine are required laboratory evaluations.Acute imaging with a non-contrast computed tomography(CT)scan is the diagnostic imaging modality of choice.However,concerns over radiation exposure have led towards low-dose and even ultra-low-dose protocols for the detection of urinary calculi.Low-dose non-contrast CT scans are now standard of care for the initial diagnosis of renal colic in patients with a body mass index≤30.Medical expulsive therapy is recommended for patients with a ureteral calculus<10 mm and no signs of infection.Emergency urinary decompression is mandatory for a specific subset of patients,especially those with infection.Although limited data exists,emergency ureteroscopy or even shock wave lithotripsy may also betherapeutic options.展开更多
Chronic constipation is a common and extremely troublesome disorder that significantly reduces the quality of life,and this fact is consistent with the high rate at which health care is sought for this condition.The a...Chronic constipation is a common and extremely troublesome disorder that significantly reduces the quality of life,and this fact is consistent with the high rate at which health care is sought for this condition.The aim of this project was to develop a consensus for the diagnosis and treatment of chronic constipation and obstructed defecation.The commission presents its results in a "Question-Answer" format,including a set of graded recommendations based on a systematic review of the literature and evidence-based medicine.This section represents the consensus for the diagnosis.The history includes information relating to the onset and duration of symptoms and may reveal secondary causes of constipation.The presence of alarm symptoms and risk factors requires investigation.The physical examination should assess the presence of lesions in the anal and perianal region.The evidence does not support the routine use of blood testing and colonoscopy or barium enema for constipation.Various scoring systems are available to quantify the severity of constipation;the Constipation Severity Instrument for constipation and the obstructed defecation syndrome score for obstructed defecation are the most reliable.The Constipation-Related Quality of Life is an excellent tool for evaluating the patient's quality of life.No single test provides a pathophysiological basis for constipation.Colonic transit and anorectal manometry define the pathophysiologic subtypes.Balloon expulsion is a simple screening test for defecatory disorders,but it does not define the mechanisms.Defecography detects structural abnormalities and assesses functional parameters.Magnetic resonance imaging and/or pelvic floor sonography can further complement defecography by providing information on the movement of the pelvic floor and the organs that it supports.All these investigations are indicated to differentiate between slow transit constipation and obstructed defecation because the treatments differ between these conditions.展开更多
Based on a detailed survey of the distribution and organic geochemical characteristics of potential source rocks in the South Slope of the Niuzhuang Sag, Bohai Bay Basin, eastern China, a new approach to assess the am...Based on a detailed survey of the distribution and organic geochemical characteristics of potential source rocks in the South Slope of the Niuzhuang Sag, Bohai Bay Basin, eastern China, a new approach to assess the amount of hydrocarbons generated and expelled has been developed. The approach is applicable to evaluate hydrocarbons with different genetic mechanisms. The results show that the models for hydrocarbon generation and expulsion vary with potential source rocks, depending on thermal maturity, types of organic matter and paleoenvironment. Hydrocarbons are mostly generated and expelled from source rocks within the normal oil window. It was calculated that the special interval (algal-rich shales of the ES4 member formed in brackish environments) in the South Slope of the Niuzhuang Sag has a much higher potential of immature oil generation than the other intervals in the area. This suggests that hydrocarbons can definitely be generated in early diagenesis, especially under certain special geological settings. The proportion of hydrocarbons generated and expelled from the ES4 shales in the early diagenetic stage is up to 26.75% and 17.36%, respectively. It was also observed that laminated shales have a much higher expulsion efficiency than massive mudstones. In contrast, the special interval of the ES4 shales proposed from previous studies is probably not the whole rock for oil in the South Slope of the Niuzhuang Sag because of the small proportion of the gross volume and corresponding low percentage of hydrocarbons generated and expelled. A much lower expulsion efficiency of the source rock during the early stage relative to that within the normal oil window has been calculated. Our results indicate that the ES4 mudstones rather than the shales deposited in the Niuzhuang and Guangli Sag are the main source rocks for the oil discovered.展开更多
The hydrocarbon charge history of the Paleogene in the northern Dongpu Depression was analyzed in detail based on a comprehensive analysis of the generation and expulsion history of the major hydrocarbon source rocks,...The hydrocarbon charge history of the Paleogene in the northern Dongpu Depression was analyzed in detail based on a comprehensive analysis of the generation and expulsion history of the major hydrocarbon source rocks, fluorescence microscopic features and fluid inclusion petrography. There were two main stages of hydrocarbon generation and expulsion of oil from the major hydrocarbon source rocks. The first stage was the main hydrocarbon expulsion stage. The fluorescence microscopic features also indicated two stages of hydrocarbon accumulation. Carbonaceous bitumen, asphaltene bitumen and colloidal bitumen reflected an early hydrocarbon charge, whereas the oil bitumen reflected a second hydrocarbon charge. Hydrocarbon inclusions also indicate two distinct charges according to the diagenetic evolution sequence, inclusion petrography features combined with the homogenization temperature and reservoir burial history analysis. According to these comprehensive analysis results, the hydrocarbon charge history of the Paleogene reservoir in the northern Dongpu Depression was divided into two phases. The first phase was from the late Dongying depositional period of the Oligocene to the early uplift stages of the late Paleogene. The second phase was from the late Minghuazhen period of the Pliocene to the Quaternary. Reservoirs formed during the first period were widely distributed covering the entire area. In contrast,reservoirs formed during the second period were mainly distributed near the hydrocarbon generation sags. Vertically, it was characterized by a single phase in the upper layers and two phases in the lower layers of the Paleogene.展开更多
Hydrocarbon expulsion features and resource potential evaluation of source rocks are crucial for the petroleum exploration.High-maturity marine source rocks have not exhibited a hydrocarbon expulsion mode owing to the...Hydrocarbon expulsion features and resource potential evaluation of source rocks are crucial for the petroleum exploration.High-maturity marine source rocks have not exhibited a hydrocarbon expulsion mode owing to the lack of low-maturity source rocks in deep petroliferous basins.We considered the Ediacaran microbial dolomite in the Sichuan Basin,the largest high-maturity marine gas layer in China,to exhibit a method that quantitatively characterizes the hydrocarbon expulsion of high-maturity marine source rocks.The experiment of fluid inclusion,rock pyrolysis,and vitrinite reflectance(Ro)of 119 microbial dolomite core samples obtained from the Dengying Formation were performed.A hydrocarbon expulsion model of high-maturity source rock was established,and its resource potential was evaluated.The results showed that the Ediacaran microbial dolomite in the Sichuan Basin is a good source rock showing vast resource potential.The hydrocarbon expulsion threshold is determined to be vitrinite reflectance at 0.92%.The hydrocarbon expulsion intensities in the geologic history is high with maximum of 1.6×10^(7)t/km^(2).The Ediacaran microbial dolomite expelled approximately 1.008×10^(12)t of hydrocarbons,and the recoverable resource was 1.5×10^(12)m^(3).The region can be categorized into areasⅠ,Ⅱ,Ⅲ,andⅣ,in decreasing order of hydrocarbon expulsion intensity.Areas with a higher hydrocarbon expulsion intensity have a lower drilling risk and should be prioritized for exploration in the orderⅠ>Ⅱ>Ⅲ>Ⅳ.Two areas,northern and central parts of Ediacaran in the Sichuan Basin,were selected as prospects which had the drilling priority in the future gas exploration.The production data of 55 drilled wells verified the high reliability of this method.This model in this study does not require low-maturity samples and can be used for evaluating high-maturity marine source rocks,which has broad applicability in deep basins worldwide.展开更多
Taking the Jiyang depression as an example,this paper discusses the control of the formation of lithological reservoir by surrounding rocks by integrated application of geological analysis,physical simulation,and the ...Taking the Jiyang depression as an example,this paper discusses the control of the formation of lithological reservoir by surrounding rocks by integrated application of geological analysis,physical simulation,and the analysis of oil&gas accumulation mechanism.Geological statistical shows that the major burial depth and interval of lithological reservoirs in the Jiyang depression are related to the hydrocarbon generation in and expulsion from the Lower Tertiary source rocks and the time of the formation of most lithological reservoirs coincides with the peak of hydrocarbon generation and expulsion.The lithological traps located in the center of effective source rocks are propitious to high oil saturation than those located on the margin of effective source rocks.The hydrocarbon charge degree of the lithological reservoir has a positive correlation with the intensity of hydrocarbon expulsion from surrounding source rocks.Geological analyses and NMR experiments also show that the oil saturation of surrounding source rocks control the hydrocarbon potential of lithological traps,and a critical value for oil saturation of surrounding mudstone is required,that is,when the oil saturation of surrounding mudstone is lower than this critical value,no oil and gas accumulate in the lithological trap.The control of surrounding mudstone on the oil-bearing properties of lithological reservoirs is also analyzed by the mechanisms of hydrocarbon generation and expulsion as well as accumulation.展开更多
The theory of ＂source rock control＂ has evolved from source-rock-control hydrocarbon accumulation, to effective source-rock-control hydrocarbon accumulation, and to high-quality source- rock-control hydrocarbon accu...The theory of ＂source rock control＂ has evolved from source-rock-control hydrocarbon accumulation, to effective source-rock-control hydrocarbon accumulation, and to high-quality source- rock-control hydrocarbon accumulation. However, there are problems, such as whether high-quality source rocks exist or not？ What high-quality source rocks are, and how to identify them, are yet to be agreed upon. Aimed at this issue of concern to explorationists, and taking the Beier Sag in the Hailaer Basin as an example, this paper defines the high-quality source rocks and the lower limit for evaluation of high-quality source rocks, by using the inflection point on the relationship curve of hydrocarbon （oil） expulsion, which is calculated by the material balance principle, versus total organic carbon （TOC）. The results show that when TOC is low, all source rocks have limited hydrocarbon expulsion and slow growth rate, thus they cannot be high-quality source rocks. However, when TOC rises to some threshold, hydrocarbon expulsion increases significantly with TOC. This inflection point should be the lower limit of high-quality source rocks： those with TOC greater than the inflection-point value are high-quality source rocks. In addition, the lower limit of high-quality source rocks is also related to the type and maturity of organic matters in the source rocks, as well as the mineral components of the source rocks affecting the residual hydrocarbons. Theoretically, the lower limit of high-quality source rocks depends on geological conditions rather than being a constant value. However, for the sake of simplicity and practicability, in this paper TOC=2.0% is regarded as the lower limit of high-quality source rocks. The examination of such standard in the work area indicates that the high-quality source rocks in members K^n2 and K^n~ of the Nantun formation contribute 76% and 82% to oil generation, and 96% and 91% to oil expulsion, respectively. The distribution of high-quality source rocks is also closely related to the distribution of hydrocarbon reservoirs in the region, demonstrating that high-quality source rocks control hydrocarbon accumulation.展开更多
Polygonal faults,generally distributed in fine-grained sediments,are layer-bound faults and are important in hydrocarbon accumulation.Using 3D seismic data,we analyzed the plane and profile features of faults develope...Polygonal faults,generally distributed in fine-grained sediments,are layer-bound faults and are important in hydrocarbon accumulation.Using 3D seismic data,we analyzed the plane and profile features of faults developed in the Qingshankou formation of the Sanzhao sag.We identified these faults as having typical features of polygonal faults:1) layer-bound;2) normal faults;3) slight fault displacements and steep in dip angles;4) multi-directional in strike and 5) a single fault has a short horizontal extension.In addition,these faults intersect each other and form polygons.These polygonal faults are the result from the combined action of compaction,volume contraction and episodic hydraulic fracturing,conditions favorable for oil/gas accumulation.They are the dominant channels for migration of fluids in the Qingshankou mudstone,forming a large number of fault-lithologic oil traps.Polygonal faults improve reservoirs.展开更多
Research on effective source rocks directly affects the accuracy of identifying hydrocarbon resources, and indirectly affects the exploration decisions in petroliferous basins. Although the previous evaluation methods...Research on effective source rocks directly affects the accuracy of identifying hydrocarbon resources, and indirectly affects the exploration decisions in petroliferous basins. Although the previous evaluation methods of effective source rocks vary relatively widely, a complete quantitative evaluation approach has not yet been developed. For that reason, we redefined the concept of effective source rocks based on the existing research results. Surrounding this definition, and guided by the hydrocarbon expulsion theory, the quantitative model called ＂two stages and three steps＂ method is established to predict effective source rocks. Its application in the Bozhong Depression indicates that among the four sets source rocks in the Bozhong Depression, the Member 3 of the Shahejie Formation （Es 3 ） has the largest effective source rock thickness, and the Member 1 Member 2 of the Shahejie Formation （Es 1＋2 ） is the second largest .The effective part of dark mudstone is only 30%-80% of the total volume and with the increase of buried depth and improvement of quality, the effective part increases. Comprehensive analysis indicates that the ＂two stages and three steps＂ method is a practical technique for effective source rock prediction.展开更多
Based on the theory of formation dynamics of oil/gas pools, the Dongying sag can be divided into three dynamic systems regarding the accumulation of oil and gas： the superpressure closed system, the semi-closed syste...Based on the theory of formation dynamics of oil/gas pools, the Dongying sag can be divided into three dynamic systems regarding the accumulation of oil and gas： the superpressure closed system, the semi-closed system and the normal pressure open system. Based on the analysis of genesis of superpressure in the superpressure closed system and the rule of hydrocarbon expulsion, it is found that hydrocarbon generation is related to superpressure, which is the main driving factor of hydrocarbon migration. Micro fractures formed by superpressure are the main channels for hydrocarbon migration. There are three dynamic patterns for hydrocarbon expulsion： free water drainage, hydrocarbon accumulation and drainage through micro fissures. In the superpressure closed system, the oil-driving-water process and oil/gas accumulation were completed in lithologic traps by way of such two dynamic patterns as episodic evolution of superpressure systems and episodic pressure release of faults. The oil-bearing capacity of lithologic traps is intimately related to reservoir-forming dynamic force. Quantitative evaluation of dynamic conditions for pool formation can effectively predict the oil-bearing capability of traps.展开更多
Based on the results of drilling,tests and simulation experiments,the shales of the Cretaceous Qingshankou Formation in the Gulong Sag of the Songliao Basin are discussed with respect to hydrocarbon generation evoluti...Based on the results of drilling,tests and simulation experiments,the shales of the Cretaceous Qingshankou Formation in the Gulong Sag of the Songliao Basin are discussed with respect to hydrocarbon generation evolution,shale oil occurrence,and pore/fracture evolution mechanism.In conjunction with a substantial amount of oil testing and production data,the Gulong shale oil enrichment layers are evaluated and the production behaviors and decline law are analyzed.The results are drawn in four aspects.First,the Gulong shales are in the stage of extensive hydrocarbon expulsion when R_(0) is 1.0%-1.2%,with the peak hydrocarbon expulsion efficiency of 49.5%approximately.In the low-medium maturity stage,shale oil migrates from kerogen to rocks and organic pores/fractures.In the medium-high maturity stage,shale oil transforms from adsorbed state to free state.Second,the clay mineral intergranular pores/fractures,dissolution pores,and organic pores make up the majority of the pore structure.During the transformation,clay minerals undergo significant intergranular pore/fracture development between the minerals such as illite and illite/smectite mixed layer.A network of pores/fractures is formed by organic matter cracking.Third,free hydrocarbon content,effective porosity,total porosity,and brittle mineral content are the core indicators for the evaluation of shale oil enrichment layers.Class-I layers are defined as free hydrocarbon content equal or greater than 6.0 mg/g,effective porosity equal or greater than 3.5%,total porosity equal or greater than 8.0%,and brittle mineral content equal or greater than 50%.It is believed that the favourable oil layers are Q2-Q3 and Q8-Q9.Fourth,the horizontal wells in the core area of the light oil zone exhibit a high cumulative production in the first year,and present a hyperbolic production decline pattern,with the decline index of 0.85-0.95,the first-year decline rate of 14.5%-26.5%,and the single-well estimated ultimate recovery(EUR)greater than 2.0×10^(4)t.In practical exploration and production,more efforts will be devoted to the clarification of hydrocarbon generation and expulsion mechanisms,accurate testing of porosity and hydrocarbon content/phase of shale under formation conditions,precise delineation of the boundary of enrichment area,relationship between mechanical properties and stimulated reservoir volume,and enhanced oil recovery,in order to improve the EUR and achieve a large-scale,efficient development of shale oil.展开更多
To identify the determinant of the occurrence of IUD expulsion Materials & Methods Based on 25 733 IUD uses from the Chinese Two per Thousand Fertility Survey data, this study examines the patterns and differe...To identify the determinant of the occurrence of IUD expulsion Materials & Methods Based on 25 733 IUD uses from the Chinese Two per Thousand Fertility Survey data, this study examines the patterns and differentials of IUD expulsion rate by characteristics of women, and identifies the socio demographic determinants of IUD expulsion. A Life Table method was used to calculate the cumulative expulsion rate and a random effects discrete time survival model was employed to assess the impact of potential determinants simultaneously on the risk of expelling an IUD. Results Three major findings are observed in this study. First, IUD expulsion was the second main reason, after pregnancy during IUD use, for IUD discontinuation during the first four years of IUD insertion; the expulsion rates were 6.4%, 9.1%, 10.8 %, and 12.0% at 12, 24, 36 and 48 months, respectively. Second, there was a clustering of IUD expulsion: some women experienced repeated IUD expulsions. Third, some socio demographic characteristics and fertility history were associated with the occurrence of IUD expulsion. In particular, the expulsion rate was high among young women, among those with two or more children and among those living in rural areas. Conclusion The above mentioned factors shoald be addressed in order to decrease the IUD expulsion rate and enhance the reprocluctive he alth of women.展开更多
Tight-sand gas in the Jurassic and shale gas within the fifth member of Xujiahe Formation （T3xs） in the Western Sichuan Basin （WSD） are currently regarded as the most prolific emerging unconventional gas plays in ...Tight-sand gas in the Jurassic and shale gas within the fifth member of Xujiahe Formation （T3xs） in the Western Sichuan Basin （WSD） are currently regarded as the most prolific emerging unconventional gas plays in China. This study conducted a conventional evaluation of T3x5 source rocks in the WSD, and investigated their hydrocarbon generation and expulsion characteristics, including intensity, efficiency and amount. The results show that, the T3x5 source rocks are thick （generally 〉200 m）, and have a high total organic content （TOC）, ranging from 2.5 to 4.5 wt%. It is thus indivative of a great hydrocarbon generation potential when they underwent high thermal evolution （Ro〉1.2%） in the area. In addition, an improved method of hydrocarbon generation potential is applied, indicating that the source rocks reached a hydrocarbon expulsion threshold with vitrinite reflectance （Ro） reaching 1.06%. and that the comprehensive hydrocarbon expulsion efficiency is about 60%. The amount of hydrocarbon generation and expulsion from Tax5 source rocks is 3.14x10^10 t and 1.86x10^10 t, respectively, with a residual amount of 1.28x10^10t within them. Continuous-type tight-sand gas is predicted to have developed in the Jurassic in the Chengdu Sag of the WSD because of the good source-reservoir configuration; the Jurassic sandstone reservoirs are tight, and the gas expelled from the T3xs source rocks migrates for very short distances vertically and horizontally. The amount of gas accumulation in the Jurassic reservoirs derived from T3x5 source rocks is up to 9.3x10s t. Geological resources of shale gas are up to 1.05x10TM t. Small differences between the amounts calculated by the volumetric method and those obtained by hydrocarbon generation potential method may be due to other gas accumulations present within interbedded sands associated with gas shales.展开更多
基金Supported by National Natural Science Foundation of China(No.82171087No.82201228)+1 种基金Natural Science Foundation of Hunan Province(No.2024JJ6570)the Scientific Research Launch Project for new employees of the Second Xiangya Hospital of Central South University.
文摘Dear Editor,We present the reported case of repetitive bilateral suprachoroidal expulsive hemorrhage(SEH)after anti-glaucoma surgeries.SEH is a rare but potentially devastating complication of intraocular surgery.Long-term ocular hypertension,high myopia,older age,arterial sclerosis,and aphakia have been reported as preoperative risk factors for developing SEH^([1]).The prognosis for the visual acuity is poor without proper management.A suggested time for surgical drainage is said to be 10-14d when the hemorrhagic clot begins to liquefy^([2]).
文摘Introduction: One of the most common disorders of the urinary tract is Urolithiasis. Twenty percent of lithiasis are located in the ureter of which 68% are seen in the distal ureter. The concept of medical expulsive therapy (MET) has been developed with enough knowledge of the ureter physiology in order to make easier the spontaneous expulsion of the stone. The aim of this study was to evaluate the efficacy and safety of three different drugs for the treatment of pelvic ureteral stones. Materiel and Methods: Between October 2017 and November 2018, 90 adult patients presenting with low or non-obstructive pelvic ureteral stones sized 8 to 10 mm were included. They were prospectively randomized, using computer-based randomization charts, into three equal groups: treatment with ketoprofen 100 mg once daily (Group I), silodosin 8 mg once daily (Group II) and tadalafil 5 mg once daily (Group III). The aim was to compare spontaneous expulsion of stone between those drugs Results: The mean expulsion time from the start of MET was 11.5 ± 3.27 days for ketoprofen group, 10.71 ± 3.98 days for silodosin group and 10.57 ± 3.40 days for tadalafil group. But these differences were also not significant (P = 0.79). The use of analgesics (grade II) was higher in groups II and III compared to group I, but without significant difference (23.33% in group I, 33.33% in group II and 40% in group III, p = 0.38). Discussion: The overall chance of spontaneous passage is low when the stone diameter is sized more than 7 mm. A wide range of spontaneous passage rates have been reported in the literature, varying from 71% to 98% for distal ureteral stones less than 5 mm and 25% - 53% for stone sized 5 to 10 mm with a mean expulsion time of more than 10 days. Conclusion: The three drugs have a low expulsion rate for 8, 9 and 10 mm pelvic ureteral stones with a higher adverse event rate for the NSAID group.
文摘Objective: To review the evidence for tamsulosin as medical expulsive therapy in enhancing the effectiveness of distal ureteral stone clearance rate. Methods: We searched Pubmed/Medline, Embase, CBM and the Cochrane Library up to October 2011. All randomized controlled trials in which tamsulosin was evaluated with distal ureterolithiasis were eligible for the analysis. Outcome measure assessed was stone clearance rate. Two authors independently assessed study quality and extracted data. All data were analyzed using RevMan 5.1. Results: Thirteen studies involving 1067 participants met the inclusion criteria. Study duration ranged from 7 to 42 d. The pooled analysis showed an improvement of 41% in stone clearance rate of tamsulosin as medical expulsive therapy for distal ureteral calculi (RR=1.41, 95% CI=1.18 to 1.70). According to stone size (6 mm<size<10 mm, 5 mm<size<6 mm, size <5 mm), the pooling effects of tamsulosin were analyzed, with a higher stone expulsion rate obtained than control (RR=1.52, 1.75, 1.05, 95% CI=1.30 to 1.77, 1.25 to 2.45, 0.95 to 1.16, respectively). Adverse effects of tamsulosin, mainly retrograde ejaculation, dizziness and hypotension, were reported in 7 included trials. Conclusion: Treatment with tamsulosin appears to be a safe and effective medical expulsion therapy for distal ureterolithiasis. To make a definite clinical recommendation to use tamsulosin as medical expulsive treatment for distal ureteral calculi, high quality multicentric, randomized, double blinded, controlled trials are necessary to prove its efficacy.
文摘Objective:Medical expulsive therapy(MET)is a suitable option for facilitating stone expulsion in patients with distal ureteral stones.This meta-analysis was conducted to compare efficacy and safety of monotherapy and combination therapy with tamsulosin,silodosin,and tadalafil on stone expulsion rate(SER)and stone expulsion time(SET),as well as their comparative safety,numbers of colic pain episodes,and need for analgesics.Methods:Randomized controlled trials were retrieved by searching PubMed,Scopus,and Web of Science up to November 27,2023.Hand-searching was also conducted in Google Scholar to find additional records.Papers in English that compared the safety and efficacy of at least two of the above agents in adults with distal ureteral stones≤10 mm were included.Results:In total,27 studies were identified(six studies through database searches and 21 through checking reference lists and hand-searching in Google Scholar).More than half of them(n=15,56%)were conducted in India.The SER significantly improved with silodosin compared with tamsulosin(odds ratio[OR]2.24,p<0.001),whereas the difference in SET was non-significant.Tadalafil achieved a significantly higher SER compared with tamsulosin(OR 1.42,p=0.042)without any difference in SET.Subgroup analysis of 5-and 10-mg doses of tadalafil showed no significant difference in SER or SET.We found no significant difference in need for analgesics(mean difference(MD−53.73,p=0.2)or the mean number of colic episodes(MD−0.42,p=0.060)between tadalafil and tamsulosin.SER or SET was not significantly different between silodosin and tadalafil.Tadalafil plus tamsulosin led to a significantly higher SER(OR 1.87,p<0.001)and SET(MD−2.99,p=0.002)compared with tamsulosin,without any significant difference in adverse effects.Conclusion:Compared with tamsulosin,SER significantly improved with silodosin,tadalafil,and the combination of tadalafil plus tamsulosin.Meanwhile,the difference in SET was only significant between tadalafil plus tamsulosin versus tamsulosin.It appears that tadalafil and silodosin have similar efficacy in SET and SER.All medical expulsive therapies had comparable safety.
基金Supported by the National Natural Science Foundation(42202133,42072174,42130803,41872148)PetroChina Science and Technology Innovation Fund(2023DQ02-0106)PetroChina Basic Technology Project(2021DJ0101).
文摘Taking the Lower Permian Fengcheng Formation shale in Mahu Sag of Junggar Basin,NW China,as an example,core observation,test analysis,geological analysis and numerical simulation were applied to identify the shale oil micro-migration phenomenon.The hydrocarbon micro-migration in shale oil was quantitatively evaluated and verified by a self-created hydrocarbon expulsion potential method,and the petroleum geological significance of shale oil micro-migration evaluation was determined.Results show that significant micro-migration can be recognized between the organic-rich lamina and organic-poor lamina.The organic-rich lamina has strong hydrocarbon generation ability.The heavy components of hydrocarbon preferentially retained by kerogen swelling or adsorption,while the light components of hydrocarbon were migrated and accumulated to the interbedded felsic or carbonate organic-poor laminae as free oil.About 69% of the Fengcheng Formation shale samples in Well MY1 exhibit hydrocarbon charging phenomenon,while 31% of those exhibit hydrocarbon expulsion phenomenon.The reliability of the micro-migration evaluation results was verified by combining the group components based on the geochromatography effect,two-dimension nuclear magnetic resonance analysis,and the geochemical behavior of inorganic manganese elements in the process of hydrocarbon migration.Micro-migration is a bridge connecting the hydrocarbon accumulation elements in shale formations,which reflects the whole process of shale oil generation,expulsion and accumulation,and controls the content and composition of shale oil.The identification and evaluation of shale oil micro-migration will provide new perspectives for dynamically differential enrichment mechanism of shale oil and establishing a“multi-peak model in oil generation”of shale.
文摘The paleo-temperature(Th)data from fluid inclusions are utilized for thermal history modelling using PetroMod software.Generally,bottom hole temperature(BHT)and vitrinite reflectance(Ro)measurements are widely used in petroleum system modelling(PSM)in the oil industry for calibration purposes.Th representing the minimum temperature of fluid entrapment estimated from fluid-inclusion study provides extra support to build the thermal models for PSM.Fluid inclusion parameters along with Rock-Eval pyrolysis analysis have been used to predict the maturity of oil in terms of API gravity as well as the maturity of source rocks respectively.Two exploratory wells RV-1(Mumbai Offshore Basin)and KK4C-A-1(Kerala-Konkan Offshore Basin),India were examined and the T_(h)from most of the fluid inclusions of wells RV-1 and KK4C-A-1 fell in the oil window range of 60-140℃suggesting thermal conditions favourable for oil generation in both of the wells.T_(h)of coeval aqueous inclusions along with the Hydrocarbon Fluid inclusions(HCFIs)was used to calibrate PSM.Vital parameters show that source rocks of well RV-1 are mature and that of well KK4C-A-1 are immature.Two sets of PSM are created in terms of generation and expulsion for the dry wells RV-1 and KK4C-A-1 and calibrated each well using fluid inclusion Th and BHT.From the fluid inclusion analysis method,it is evident that hydrocarbon generation happened in both wells and the paleo-temperature indicates that the formations of both wells were subjected to temperatures in the oil window range,even though it was designated as dry wells in the present scenario.The present study highlights the application of fluid inclusion paleo-temperature(Th)during calibration instead of commonly used methods.We could obtain desirable and accurate data output from PSM using T_(h) calibration.
文摘Over half a million patients present to emergency departments and nearly 3 million patients visit healthcare providers annually due to problems associated with urolithiasis.Despite updated guidelines from the American Urological Association and European Association of Urology for the evaluation and management of nephrolithiasis,considerable variability still exists regarding treatment for acute symptomatic upper urinary tract stones.Therefore,this article will review the current evaluation and management of acute symptomatic nephrolithiasis.Initial management includes analgesia and antiemetics.Additionally,a urinalysis and creatinine are required laboratory evaluations.Acute imaging with a non-contrast computed tomography(CT)scan is the diagnostic imaging modality of choice.However,concerns over radiation exposure have led towards low-dose and even ultra-low-dose protocols for the detection of urinary calculi.Low-dose non-contrast CT scans are now standard of care for the initial diagnosis of renal colic in patients with a body mass index≤30.Medical expulsive therapy is recommended for patients with a ureteral calculus<10 mm and no signs of infection.Emergency urinary decompression is mandatory for a specific subset of patients,especially those with infection.Although limited data exists,emergency ureteroscopy or even shock wave lithotripsy may also betherapeutic options.
基金Supported by Associazione Italiana Gastroenterologi and Endoscopisti Digestivi Ospedalieri via N Colajanni,4-00191 Roma,ItalySocietà Italiana di Chirurgia Colo-Rettale via Medici,23-10143Torino,Italy
文摘Chronic constipation is a common and extremely troublesome disorder that significantly reduces the quality of life,and this fact is consistent with the high rate at which health care is sought for this condition.The aim of this project was to develop a consensus for the diagnosis and treatment of chronic constipation and obstructed defecation.The commission presents its results in a "Question-Answer" format,including a set of graded recommendations based on a systematic review of the literature and evidence-based medicine.This section represents the consensus for the diagnosis.The history includes information relating to the onset and duration of symptoms and may reveal secondary causes of constipation.The presence of alarm symptoms and risk factors requires investigation.The physical examination should assess the presence of lesions in the anal and perianal region.The evidence does not support the routine use of blood testing and colonoscopy or barium enema for constipation.Various scoring systems are available to quantify the severity of constipation;the Constipation Severity Instrument for constipation and the obstructed defecation syndrome score for obstructed defecation are the most reliable.The Constipation-Related Quality of Life is an excellent tool for evaluating the patient's quality of life.No single test provides a pathophysiological basis for constipation.Colonic transit and anorectal manometry define the pathophysiologic subtypes.Balloon expulsion is a simple screening test for defecatory disorders,but it does not define the mechanisms.Defecography detects structural abnormalities and assesses functional parameters.Magnetic resonance imaging and/or pelvic floor sonography can further complement defecography by providing information on the movement of the pelvic floor and the organs that it supports.All these investigations are indicated to differentiate between slow transit constipation and obstructed defecation because the treatments differ between these conditions.
基金This study is part of the China National“973”Key Research and Development Program#G199943310a Professional Enhancement Program of the Natural Resources of Canada Earth Science Sector,under the collaborative research agreement between the Geological Survey of Canada(Calgary)and the University of Petroleum(Beijing)+1 种基金The funding for this project was provided by the National Natural Science Foundation of China(under the“973”National Key Research and Development Program of China#G1999043310)the Geological Survey of Canada and the Chinese National Petrochemical Corporation.
文摘Based on a detailed survey of the distribution and organic geochemical characteristics of potential source rocks in the South Slope of the Niuzhuang Sag, Bohai Bay Basin, eastern China, a new approach to assess the amount of hydrocarbons generated and expelled has been developed. The approach is applicable to evaluate hydrocarbons with different genetic mechanisms. The results show that the models for hydrocarbon generation and expulsion vary with potential source rocks, depending on thermal maturity, types of organic matter and paleoenvironment. Hydrocarbons are mostly generated and expelled from source rocks within the normal oil window. It was calculated that the special interval (algal-rich shales of the ES4 member formed in brackish environments) in the South Slope of the Niuzhuang Sag has a much higher potential of immature oil generation than the other intervals in the area. This suggests that hydrocarbons can definitely be generated in early diagenesis, especially under certain special geological settings. The proportion of hydrocarbons generated and expelled from the ES4 shales in the early diagenetic stage is up to 26.75% and 17.36%, respectively. It was also observed that laminated shales have a much higher expulsion efficiency than massive mudstones. In contrast, the special interval of the ES4 shales proposed from previous studies is probably not the whole rock for oil in the South Slope of the Niuzhuang Sag because of the small proportion of the gross volume and corresponding low percentage of hydrocarbons generated and expelled. A much lower expulsion efficiency of the source rock during the early stage relative to that within the normal oil window has been calculated. Our results indicate that the ES4 mudstones rather than the shales deposited in the Niuzhuang and Guangli Sag are the main source rocks for the oil discovered.
基金supported by the Important National Science&Technology Specific Projects(Grant No.2011ZX05006-003/004)
文摘The hydrocarbon charge history of the Paleogene in the northern Dongpu Depression was analyzed in detail based on a comprehensive analysis of the generation and expulsion history of the major hydrocarbon source rocks, fluorescence microscopic features and fluid inclusion petrography. There were two main stages of hydrocarbon generation and expulsion of oil from the major hydrocarbon source rocks. The first stage was the main hydrocarbon expulsion stage. The fluorescence microscopic features also indicated two stages of hydrocarbon accumulation. Carbonaceous bitumen, asphaltene bitumen and colloidal bitumen reflected an early hydrocarbon charge, whereas the oil bitumen reflected a second hydrocarbon charge. Hydrocarbon inclusions also indicate two distinct charges according to the diagenetic evolution sequence, inclusion petrography features combined with the homogenization temperature and reservoir burial history analysis. According to these comprehensive analysis results, the hydrocarbon charge history of the Paleogene reservoir in the northern Dongpu Depression was divided into two phases. The first phase was from the late Dongying depositional period of the Oligocene to the early uplift stages of the late Paleogene. The second phase was from the late Minghuazhen period of the Pliocene to the Quaternary. Reservoirs formed during the first period were widely distributed covering the entire area. In contrast,reservoirs formed during the second period were mainly distributed near the hydrocarbon generation sags. Vertically, it was characterized by a single phase in the upper layers and two phases in the lower layers of the Paleogene.
基金supported by the Open Fund Project of State Key Laboratory of Lithospheric Evolution [SKL-K202103]support of the Exploration and Development Research Institute of Petro China Southwest Oil & Gas Field
文摘Hydrocarbon expulsion features and resource potential evaluation of source rocks are crucial for the petroleum exploration.High-maturity marine source rocks have not exhibited a hydrocarbon expulsion mode owing to the lack of low-maturity source rocks in deep petroliferous basins.We considered the Ediacaran microbial dolomite in the Sichuan Basin,the largest high-maturity marine gas layer in China,to exhibit a method that quantitatively characterizes the hydrocarbon expulsion of high-maturity marine source rocks.The experiment of fluid inclusion,rock pyrolysis,and vitrinite reflectance(Ro)of 119 microbial dolomite core samples obtained from the Dengying Formation were performed.A hydrocarbon expulsion model of high-maturity source rock was established,and its resource potential was evaluated.The results showed that the Ediacaran microbial dolomite in the Sichuan Basin is a good source rock showing vast resource potential.The hydrocarbon expulsion threshold is determined to be vitrinite reflectance at 0.92%.The hydrocarbon expulsion intensities in the geologic history is high with maximum of 1.6×10^(7)t/km^(2).The Ediacaran microbial dolomite expelled approximately 1.008×10^(12)t of hydrocarbons,and the recoverable resource was 1.5×10^(12)m^(3).The region can be categorized into areasⅠ,Ⅱ,Ⅲ,andⅣ,in decreasing order of hydrocarbon expulsion intensity.Areas with a higher hydrocarbon expulsion intensity have a lower drilling risk and should be prioritized for exploration in the orderⅠ>Ⅱ>Ⅲ>Ⅳ.Two areas,northern and central parts of Ediacaran in the Sichuan Basin,were selected as prospects which had the drilling priority in the future gas exploration.The production data of 55 drilled wells verified the high reliability of this method.This model in this study does not require low-maturity samples and can be used for evaluating high-maturity marine source rocks,which has broad applicability in deep basins worldwide.
基金Supported by National Natural Science Fund 40472078 and the Project of"973 plan"G1999043310
文摘Taking the Jiyang depression as an example,this paper discusses the control of the formation of lithological reservoir by surrounding rocks by integrated application of geological analysis,physical simulation,and the analysis of oil&gas accumulation mechanism.Geological statistical shows that the major burial depth and interval of lithological reservoirs in the Jiyang depression are related to the hydrocarbon generation in and expulsion from the Lower Tertiary source rocks and the time of the formation of most lithological reservoirs coincides with the peak of hydrocarbon generation and expulsion.The lithological traps located in the center of effective source rocks are propitious to high oil saturation than those located on the margin of effective source rocks.The hydrocarbon charge degree of the lithological reservoir has a positive correlation with the intensity of hydrocarbon expulsion from surrounding source rocks.Geological analyses and NMR experiments also show that the oil saturation of surrounding source rocks control the hydrocarbon potential of lithological traps,and a critical value for oil saturation of surrounding mudstone is required,that is,when the oil saturation of surrounding mudstone is lower than this critical value,no oil and gas accumulate in the lithological trap.The control of surrounding mudstone on the oil-bearing properties of lithological reservoirs is also analyzed by the mechanisms of hydrocarbon generation and expulsion as well as accumulation.
基金funded by the 973 Prophase Special Program of China(NO.2011CB211701)National Natural Science Foundation of China(41172134)CNPC Innovation Foundation (2011D-5006-0101)
文摘The theory of ＂source rock control＂ has evolved from source-rock-control hydrocarbon accumulation, to effective source-rock-control hydrocarbon accumulation, and to high-quality source- rock-control hydrocarbon accumulation. However, there are problems, such as whether high-quality source rocks exist or not？ What high-quality source rocks are, and how to identify them, are yet to be agreed upon. Aimed at this issue of concern to explorationists, and taking the Beier Sag in the Hailaer Basin as an example, this paper defines the high-quality source rocks and the lower limit for evaluation of high-quality source rocks, by using the inflection point on the relationship curve of hydrocarbon （oil） expulsion, which is calculated by the material balance principle, versus total organic carbon （TOC）. The results show that when TOC is low, all source rocks have limited hydrocarbon expulsion and slow growth rate, thus they cannot be high-quality source rocks. However, when TOC rises to some threshold, hydrocarbon expulsion increases significantly with TOC. This inflection point should be the lower limit of high-quality source rocks： those with TOC greater than the inflection-point value are high-quality source rocks. In addition, the lower limit of high-quality source rocks is also related to the type and maturity of organic matters in the source rocks, as well as the mineral components of the source rocks affecting the residual hydrocarbons. Theoretically, the lower limit of high-quality source rocks depends on geological conditions rather than being a constant value. However, for the sake of simplicity and practicability, in this paper TOC=2.0% is regarded as the lower limit of high-quality source rocks. The examination of such standard in the work area indicates that the high-quality source rocks in members K^n2 and K^n~ of the Nantun formation contribute 76% and 82% to oil generation, and 96% and 91% to oil expulsion, respectively. The distribution of high-quality source rocks is also closely related to the distribution of hydrocarbon reservoirs in the region, demonstrating that high-quality source rocks control hydrocarbon accumulation.
基金the National Natural Science Foundation of China (No.40672143)the National Basic Research Program of China (No.2005CB 4221007)
文摘Polygonal faults,generally distributed in fine-grained sediments,are layer-bound faults and are important in hydrocarbon accumulation.Using 3D seismic data,we analyzed the plane and profile features of faults developed in the Qingshankou formation of the Sanzhao sag.We identified these faults as having typical features of polygonal faults:1) layer-bound;2) normal faults;3) slight fault displacements and steep in dip angles;4) multi-directional in strike and 5) a single fault has a short horizontal extension.In addition,these faults intersect each other and form polygons.These polygonal faults are the result from the combined action of compaction,volume contraction and episodic hydraulic fracturing,conditions favorable for oil/gas accumulation.They are the dominant channels for migration of fluids in the Qingshankou mudstone,forming a large number of fault-lithologic oil traps.Polygonal faults improve reservoirs.
文摘Research on effective source rocks directly affects the accuracy of identifying hydrocarbon resources, and indirectly affects the exploration decisions in petroliferous basins. Although the previous evaluation methods of effective source rocks vary relatively widely, a complete quantitative evaluation approach has not yet been developed. For that reason, we redefined the concept of effective source rocks based on the existing research results. Surrounding this definition, and guided by the hydrocarbon expulsion theory, the quantitative model called ＂two stages and three steps＂ method is established to predict effective source rocks. Its application in the Bozhong Depression indicates that among the four sets source rocks in the Bozhong Depression, the Member 3 of the Shahejie Formation （Es 3 ） has the largest effective source rock thickness, and the Member 1 Member 2 of the Shahejie Formation （Es 1＋2 ） is the second largest .The effective part of dark mudstone is only 30%-80% of the total volume and with the increase of buried depth and improvement of quality, the effective part increases. Comprehensive analysis indicates that the ＂two stages and three steps＂ method is a practical technique for effective source rock prediction.
文摘Based on the theory of formation dynamics of oil/gas pools, the Dongying sag can be divided into three dynamic systems regarding the accumulation of oil and gas： the superpressure closed system, the semi-closed system and the normal pressure open system. Based on the analysis of genesis of superpressure in the superpressure closed system and the rule of hydrocarbon expulsion, it is found that hydrocarbon generation is related to superpressure, which is the main driving factor of hydrocarbon migration. Micro fractures formed by superpressure are the main channels for hydrocarbon migration. There are three dynamic patterns for hydrocarbon expulsion： free water drainage, hydrocarbon accumulation and drainage through micro fissures. In the superpressure closed system, the oil-driving-water process and oil/gas accumulation were completed in lithologic traps by way of such two dynamic patterns as episodic evolution of superpressure systems and episodic pressure release of faults. The oil-bearing capacity of lithologic traps is intimately related to reservoir-forming dynamic force. Quantitative evaluation of dynamic conditions for pool formation can effectively predict the oil-bearing capability of traps.
基金Supported by the National Natural Science Foundation Project(42090020,42090025)Strategic Research of Oil and Gas Development Major Project of Ministry of Science and TechnologyPetroChina Scientific Research and Technological Development Project(2019E2601).
文摘Based on the results of drilling,tests and simulation experiments,the shales of the Cretaceous Qingshankou Formation in the Gulong Sag of the Songliao Basin are discussed with respect to hydrocarbon generation evolution,shale oil occurrence,and pore/fracture evolution mechanism.In conjunction with a substantial amount of oil testing and production data,the Gulong shale oil enrichment layers are evaluated and the production behaviors and decline law are analyzed.The results are drawn in four aspects.First,the Gulong shales are in the stage of extensive hydrocarbon expulsion when R_(0) is 1.0%-1.2%,with the peak hydrocarbon expulsion efficiency of 49.5%approximately.In the low-medium maturity stage,shale oil migrates from kerogen to rocks and organic pores/fractures.In the medium-high maturity stage,shale oil transforms from adsorbed state to free state.Second,the clay mineral intergranular pores/fractures,dissolution pores,and organic pores make up the majority of the pore structure.During the transformation,clay minerals undergo significant intergranular pore/fracture development between the minerals such as illite and illite/smectite mixed layer.A network of pores/fractures is formed by organic matter cracking.Third,free hydrocarbon content,effective porosity,total porosity,and brittle mineral content are the core indicators for the evaluation of shale oil enrichment layers.Class-I layers are defined as free hydrocarbon content equal or greater than 6.0 mg/g,effective porosity equal or greater than 3.5%,total porosity equal or greater than 8.0%,and brittle mineral content equal or greater than 50%.It is believed that the favourable oil layers are Q2-Q3 and Q8-Q9.Fourth,the horizontal wells in the core area of the light oil zone exhibit a high cumulative production in the first year,and present a hyperbolic production decline pattern,with the decline index of 0.85-0.95,the first-year decline rate of 14.5%-26.5%,and the single-well estimated ultimate recovery(EUR)greater than 2.0×10^(4)t.In practical exploration and production,more efforts will be devoted to the clarification of hydrocarbon generation and expulsion mechanisms,accurate testing of porosity and hydrocarbon content/phase of shale under formation conditions,precise delineation of the boundary of enrichment area,relationship between mechanical properties and stimulated reservoir volume,and enhanced oil recovery,in order to improve the EUR and achieve a large-scale,efficient development of shale oil.
文摘To identify the determinant of the occurrence of IUD expulsion Materials & Methods Based on 25 733 IUD uses from the Chinese Two per Thousand Fertility Survey data, this study examines the patterns and differentials of IUD expulsion rate by characteristics of women, and identifies the socio demographic determinants of IUD expulsion. A Life Table method was used to calculate the cumulative expulsion rate and a random effects discrete time survival model was employed to assess the impact of potential determinants simultaneously on the risk of expelling an IUD. Results Three major findings are observed in this study. First, IUD expulsion was the second main reason, after pregnancy during IUD use, for IUD discontinuation during the first four years of IUD insertion; the expulsion rates were 6.4%, 9.1%, 10.8 %, and 12.0% at 12, 24, 36 and 48 months, respectively. Second, there was a clustering of IUD expulsion: some women experienced repeated IUD expulsions. Third, some socio demographic characteristics and fertility history were associated with the occurrence of IUD expulsion. In particular, the expulsion rate was high among young women, among those with two or more children and among those living in rural areas. Conclusion The above mentioned factors shoald be addressed in order to decrease the IUD expulsion rate and enhance the reprocluctive he alth of women.
基金supported by the National Natural Science Foundation of China(U6212205)the Chinese Postdoctoral Science Foundation(2014M550984)
文摘Tight-sand gas in the Jurassic and shale gas within the fifth member of Xujiahe Formation （T3xs） in the Western Sichuan Basin （WSD） are currently regarded as the most prolific emerging unconventional gas plays in China. This study conducted a conventional evaluation of T3x5 source rocks in the WSD, and investigated their hydrocarbon generation and expulsion characteristics, including intensity, efficiency and amount. The results show that, the T3x5 source rocks are thick （generally 〉200 m）, and have a high total organic content （TOC）, ranging from 2.5 to 4.5 wt%. It is thus indivative of a great hydrocarbon generation potential when they underwent high thermal evolution （Ro〉1.2%） in the area. In addition, an improved method of hydrocarbon generation potential is applied, indicating that the source rocks reached a hydrocarbon expulsion threshold with vitrinite reflectance （Ro） reaching 1.06%. and that the comprehensive hydrocarbon expulsion efficiency is about 60%. The amount of hydrocarbon generation and expulsion from Tax5 source rocks is 3.14x10^10 t and 1.86x10^10 t, respectively, with a residual amount of 1.28x10^10t within them. Continuous-type tight-sand gas is predicted to have developed in the Jurassic in the Chengdu Sag of the WSD because of the good source-reservoir configuration; the Jurassic sandstone reservoirs are tight, and the gas expelled from the T3xs source rocks migrates for very short distances vertically and horizontally. The amount of gas accumulation in the Jurassic reservoirs derived from T3x5 source rocks is up to 9.3x10s t. Geological resources of shale gas are up to 1.05x10TM t. Small differences between the amounts calculated by the volumetric method and those obtained by hydrocarbon generation potential method may be due to other gas accumulations present within interbedded sands associated with gas shales.
