Deep marine carbonate rocks have become one of the key targets of onshore oil and gas exploration and development for reserves replacement in China.Further geological researches of such rocks may practically facilitat...Deep marine carbonate rocks have become one of the key targets of onshore oil and gas exploration and development for reserves replacement in China.Further geological researches of such rocks may practically facilitate the sustainable,steady and smooth development of the petroleum industry in the country.Therefore,through a deep investigation into the fundamental geological conditions of deep marine carbonate reservoirs,we found higher-than-expected resource potential therein,which may uncover large oil or gas fields.The findings were reflected in four aspects.Firstly,there are two kinds of hydrocarbon kitchens which were respectively formed by conventional source rocks and liquid hydrocarbons cracking that were detained in source rocks,and both of them can provide large-scale hydrocarbons.Secondly,as controlled by the bedding and interstratal karstification,as well as the burial and hydrothermal dolomitization,effective carbonate reservoirs may be extensively developed in the deep and ultra-deep strata.Thirdly,under the coupling action of progressive burial and annealing heating,some marine source rocks could form hydrocarbon accumulations spanning important tectonic phases,and large quantity of liquid hydrocarbons could be kept in late stage,contributing to rich oil and gas in such deep marine strata.Fourthly,large-scale uplifts were formed by the stacking of multi-episodic tectonism and oil and gas could be accumulated in three modes(i.e.,stratoid large-area reservoir-forming mode of karst reservoirs in the slope area of uplift,back-flow type large-area reservoir-forming mode of buried hill weathered crust karst reservoirs,and wide-range reservoir-forming mode of reef-shoal reservoirs);groups of stratigraphic and lithologic traps were widely developed in the areas of periclinal structures of paleohighs and continental margins.In conclusion,deep marine carbonate strata in China onshore contain the conditions for widely and intensively preserving hydrocarbons,so large oil or gas fields are expected.展开更多
In view of the characteristics of deep marine carbonate reservoirs in the Sichuan Basin,such as a deep burial depth(5000-8120 m),high temperatures(150℃-180℃),a large inclination toward wells,and large acid-rock reac...In view of the characteristics of deep marine carbonate reservoirs in the Sichuan Basin,such as a deep burial depth(5000-8120 m),high temperatures(150℃-180℃),a large inclination toward wells,and large acid-rock reaction rate,a high-temperature gelled acid and a preflush containing a self-generating acid that matched with the high-temperature gelled acid were developed.The results of laboratory evaluation showed that the viscosity of the high-temperature gelled acid at 180℃ was 30 mPa·s,with a corrosion rate lower than 70 g/m^(2)·h.The drag reduction and acid-rock reaction rates reached 64%-71% and 1.569×10^(-4) mol/cm^(2)·s respectively,demonstrating obvious retarding performance.In addition,the viscosity of the preflush containing a self-generating acid(after shearing at 160℃ for 1 h)remained at 200 mPa·s.Compared with a full injection of the high-temperature gelled acid,the acid-etched fracture conductivity after an alternate injection of the preflush containing self-generating and high-temperature gelled acids increased by more than 50%.Field application showed that the hightemperature gelled acid played a vital role in connecting fractures where as the preflush containing self-generating acid demonstrated an outstanding fracture-formation ability.After a three-stage alternate injection(a preflush containing self-generating and gelled acids),a remarkable stimulation effect was achieved for increase natural gas production.展开更多
A series of significant discoveries in marine carbonate rocks show great petroleum exploration potential in the Tarim Basin. However, the oil and gas fields discovered in the carbonate rocks are mainly distributed aro...A series of significant discoveries in marine carbonate rocks show great petroleum exploration potential in the Tarim Basin. However, the oil and gas fields discovered in the carbonate rocks are mainly distributed around the Manjiaer Sag in the eastern Tarim Basin. Some explorations occurred and no oil or gas field was discovered around the Awati Sag in the western Tarim Basin. Information from wells and outcrops reveals that there are excellent oil and gas source rock conditions around the Awati Sag. Transformed reef-shoal reservoirs could be formed in the Ordovician carbonate rocks with paleo-geographic background and hydrothermal conditions. Therefore, it is necessary to make a systematical study and overall evaluation of the potential of the periphery of the Awati Sag in terms of source rock evolution, resource potential, high-grade reservoir formation and distribution, and main factors controlling hydrocarbon migration and accumulation.展开更多
In recent years,deep marine carbonate gas reservoirs have become an important field in increasing conventional gas reserves and production in the Sichuan Basin.Due to complex hydrocarbon accumulation conditions,great ...In recent years,deep marine carbonate gas reservoirs have become an important field in increasing conventional gas reserves and production in the Sichuan Basin.Due to complex hydrocarbon accumulation conditions,great burial depth and complicate gas-water relation,however,this type of gas reservoirs faces huge challenges to realize efficient development.In this paper,the development history of deep marine carbonate gas reservoirs in the Sichuan Basin was analyzed.Then,based on such development characteristics and practices,special technologies were summarized.Finally,the research direction for the coming years was pointed out.And the following research results were obtained.First,the reserves of the deep marine carbonate gas reservoirs in the Sichuan Basin vary greatly in scales and types.The reservoirs are of poor quality and strong heterogeneity with active edge and bottom water.The raw gas generally contains acidic gas.What's more,most development wells are located in mountainous areas,and drilled formations are complicated in vertical distribution.Second,special technologies have been formed in the Sichuan Basin,including the fine description technology for strong-heterogeneity gas reservoirs in deep low-gentle structures,the optimized water control technology for the water-bearing gas reservoirs with developed small-scale fractures and vugs,drilling,completion and stimulation engineering technologies for deep complex gas wells,and the support technology for clean and safe development of sulfur-bearing gas reservoirs,so as to provide support for the efficient productivity construction and optimized development of giant marine carbonate reservoirs in the Sichuan Basin.Third,as the development of the carbonate gas reservoirs in the Sichuan Basin begins to convert into the gas reservoirs in ultra-deep complex structures,the next direction of technological research is the fine structure description and thin reservoir prediction technique,across-scale numerical simulation technique,drilling and completion and gas production engineering technique for deep marine carbonate gas reservoirs.It is concluded that these special technologies for the efficient development of deep marine carbonate gas reservoirs provides powerful support for PetroChina Southwest Company to build up giant gas fields with the reserves of tens of billions of cubic meters and realize the leaping growth of gas production.The research results can provide valuable technical reference for the development of deep marine carbonate gas reservoirs at home and abroad.展开更多
There are rich oil and gas resources in marine carbonate strata worldwide.Although most of the oil and gas reserves discovered so far are mainly distributed in Mesozoic,Cenozoic,and upper Paleozoic strata,oil and gas ...There are rich oil and gas resources in marine carbonate strata worldwide.Although most of the oil and gas reserves discovered so far are mainly distributed in Mesozoic,Cenozoic,and upper Paleozoic strata,oil and gas exploration in the Proterozoic–Lower Paleozoic（PLP）strata—the oldest marine strata—has been very limited.To more clearly understand the oil and gas formation conditions and distributions in the PLP marine carbonate strata,we analyzed and characterized the petroleum geological conditions,oil and gas reservoir types,and their distributions in thirteen giant oil and gas fields worldwide.This study reveals the main factors controlling their formation and distribution.Our analyses show that the source rocks for these giant oil and gas fields are mainly shale with a great abundance of type I–II organic matter and a high thermal evolution extent.The reservoirs are mainly gas reservoirs,and the reservoir rocks are dominated by dolomite.The reservoir types are mainly karst and reef–shoal bodies with well-developed dissolved pores and cavities,intercrystalline pores,and fractures.These reservoirs arehighly heterogeneous.The burial depth of the reservoirs is highly variable and somewhat negatively correlated to the porosity.The cap rocks are mainly thick evaporites and shales,with the thickness of the cap rocks positively correlated to the oil and gas reserves.The development of high-quality evaporite cap rock is highly favorable for oil and gas preservation.We identified four hydrocarbon generation models,and that the major source rocks have undergone a long period of burial and thermal evolution and are characterized by early and long periods of hydrocarbon generation.These giant oil and gas fields have diverse types of reservoirs and are mainly distributed in paleo-uplifts,slope zones,and platform margin reef-shoal bodies.The main factors that control their formation and distribution were identified,enabling the prediction of new favorable areas for oil and gas exploration.展开更多
Acid fracturing is an indispensable technology in the efficient development of carbonate oil and gas rosarvoirs.As for deep and ultra-deep marine carbonate oil and gas reservoirs,however,existing acid fracturing techn...Acid fracturing is an indispensable technology in the efficient development of carbonate oil and gas rosarvoirs.As for deep and ultra-deep marine carbonate oil and gas reservoirs,however,existing acid fracturing technologies can hardly create complex fracture networks because of their particular engineering and geological characteristics.In order to realize the efficient three-dimensional development of deep and ultra-deep marine carbonate oil and gas reservoirs,this paper revealed the acid fracturing difficulties of this kind of reservoirs based on the engineering and geological characteristics of deep marine carbonate oil and gas reservoirs in China.Then,by taking the efficient three-dimensional development of deep and ultra-deep marine carbonate oiland gas reservoirs as the target,the technical conceptof three-dimensional acid fracturing(3D-AF)was putforward based on the techniques of volume acid fracturing and deep acid fracturing.In addition,its technical connotation was il lustrated,and its key technologies were described in detail.Finally,its development direction in the next step was pointed out.And the following research results were obtained.First,the 3D-AF technology contains three basic connotations:(1)selecting the corresponding acid penetration technology according to reservoir types so as to realize sufficient resarvoir stimulation on the plane;(2)creating complex acid-fracture volume with higher flow conductivity under high closed pressure;(3)deploying acid-fracture volume rationally along the long hole section so as to realize sufficient reservoir stimulation in the wellbore direction.Second,there are three key technologies of 3D-AF,i.e.,the technology for predicting the effective acid-penetrate distance under the coupling action of multi-feld,multi-scale and multi-fluid,the technology for optimizing the flow conductivity of complex acid-fracture volume,and the technology for precisely deploying acid in the long section of horizontal well or highly deviated well.Third,in order to promote the further development of 3D-AFtechnology,it is necessary to carry out researches on three technologies,i.e.,the technology for predicting and reducing the fracturing pressure of ultra-deep reservoir,the tech-nology for predicting the geometry of acid-fracture body ina strongly heterogeneous reservoir,and the staged reservoir production technology and new fluid technology with high temperature resistance,low reaction rate and low friction resistance coefficient for long hole sections(over 7000 m).展开更多
According to the complex differential accumulation history of deep marine oil and gas in superimposed basins,the Lower Paleozoic petroleum system in Tahe Oilfield of Tarim Basin is selected as a typical case,and the p...According to the complex differential accumulation history of deep marine oil and gas in superimposed basins,the Lower Paleozoic petroleum system in Tahe Oilfield of Tarim Basin is selected as a typical case,and the process of hydrocarbon generation and expulsion,migration and accumulation,adjustment and transformation of deep oil and gas is restored by means of reservoine-forming dynamics simulation.The thermal evolution history of the Lower Cambrian source rocks in Tahe Oilfield reflects the obvious differences in hydrocarbon generation and expulsion process and intensity in different tectonic zones,which is the main reason controlling the differences in deep oil and gas phases.The complex transport system composed of strike-slip fault and unconformity,etc.controlled early migration and accumulation and late adjustment of deep oil and gas,while the Middle Cambrian gypsum-salt rock in inner carbonate platform prevented vertical migration and accumulation of deep oil and gas,resulting in an obvious"fault-controlled"feature of deep oil and gas,in which the low potential area superimposed by the NE-strike-slip fault zone and deep oil and gas migration was conducive to accumulation,and it is mainly beaded along the strike-slip fault zone in the northeast direction.The dynamic simulation of reservoir formation reveals that the spatio-temporal configuration of"source-fault-fracture-gypsum-preservation"controls the differential accumulation of deep oil and gas in Tahe Oilfield.The Ordovician has experienced the accumulation history of multiple periods of charging,vertical migration and accumulation,and lateral adjustment and transformation,and deep oil and gas have always been in the dynamic equilibrium of migration,accumulation and escape.The statistics of residual oil and gas show that the deep stratum of Tahe Oilfield still has exploration and development potential in the Ordovician Yingshan Formation and Penglaiba Formation,and the Middle and Upper Cambrian ultra-deep stratum has a certain oil and gas resource prospect.This study provides a reference for the dynamic quantitative evaluation of deep oil and gas in the Tarim Basin,and also provides a reference for the study of reservoir formation and evolution in carbonate reservoir of paleo-craton basin.展开更多
Various types of paleo-uplifts with different characteristics are developed in the Tarim Basin.Previously,there were multiple opinions on the pale-uplifts origins and structural evolution,so the oil and gas exploratio...Various types of paleo-uplifts with different characteristics are developed in the Tarim Basin.Previously,there were multiple opinions on the pale-uplifts origins and structural evolution,so the oil and gas exploration ideas and deployment in the Tarim Basin were not developed smoothly.In this paper,regional seismic interpretation and structural analysis were carried out on the deep marine carbonate rocks in this basin based on the new seismic and drilling data.Then combined with the structural denudation results,the paleo-structural frameworks were reconstructed.And finally,the formation stage and main controlling factors of paleo-uplifts were discussed.It is shown that the Middle Ordovician is the key period when regional extension was converted to compression in this basin,so stratigraphic,sedimentary and structural differences occurred.Before the deposition of Yijianfang Fm in late Middle Ordovician,three carbonate paleo-uplifts(i.e.,the Northern,Central and SW Tarim paleo-uplifts)begun to appear,and they were all broad-folded paleo-uplifts of nearly E-W striking and were formed at the same stage.The distribution and development of the Phanerozoic uplifts in this basin are restricted by the Northern and Southern Tarim basement paleuplifts of nearly E-W striking which were developed during the Precambrian.It is indicated that all the three paleo-uplifts are compressional paleo-uplifts originated from the convergence of the southern plate margin based on the basement paleo-uplifts and they are all characterized by similar structural characteristics and inherited formation and evolution.The current differences of paleo-uplifts are controlled by multi-stage intense structural reformation since the Silurian.It is concluded that the oil and gas exploration potential is immense in the carbonate reservoirs of well-preserved deep paleo-structural zones in a larger area.展开更多
The exploration of deep layers has become increasingly important in the global oil and gas industry.The Tazhong-Bachu area of the Tarim Basin is a pioneering target for deep petroleum exploration in China,but only Wel...The exploration of deep layers has become increasingly important in the global oil and gas industry.The Tazhong-Bachu area of the Tarim Basin is a pioneering target for deep petroleum exploration in China,but only Wells Zhongshen1 and Zhongshen5 have found industrial oil flow in the Cambrian.Noteworthily,the occurrence of reservoir bitumen in the Lower Cambrian coring interval in many wells indicates that large-scale hydrocarbon migration had occurred here in geological history.Effective identification of reservoir bitumen in the Cambrian dolomite reservoirs is crucial to understanding hydrocarbons'distribution and migration.In this study,we adopt the Reservoir Bitumen Index(RBI)method to deduce a quantitative calculation formula for reservoir bitumen,and classify the transport system into four types based on differences in hydrocarbon transport behavior and characteristics.The results show that the deep carbonate low permeability-tight reservoirs of the Lower Cambrian in the Tazhong-Bachu area generally develop reservoir bitumen,most likely derived from underlying Precambrian source rocks.Therefore,the Lower Cambrian carbonate reservoir is considered a near-source discrete petroleum transport system,providing great potential for further oil and gas exploration in the Lower Paleozoic in the Tazhong-Bachu area.展开更多
Combined evidence from the outcrop and the fluid inclusion assemblage(FIA)analysis indicates that there exist two episodes of fluid flow controlled by the tectonic activity.The first episode was recorded mainly in the...Combined evidence from the outcrop and the fluid inclusion assemblage(FIA)analysis indicates that there exist two episodes of fluid flow controlled by the tectonic activity.The first episode was recorded mainly in the reservoir rock of the Honghuayuan Formation,representing the fluid flow of hydrocarbon charging.The second episode occurred mainly along the fault systems,representing the fluid move-ment when the ancient oil reservoir was destroyed.The host mineral morphology,homogeneous tem-perature,and salinity of the FIAs record an episodic fluid movement.Characters of high homogenous temperature,low salinity and a quick temperature variation of the first episode fluid flow may indicate an early-stage fluid eruption,and correspondingly,fine-grained calcite was formed.Temperature of the erupted fluid tended to decrease during its mixing with the upper formation fluid and finally had the same temperature as the upper formation.From then on,the temperature was rather steady and fa-vored the growth of the coarse calcite.Due to this character of the temperature variation of the episodic fluid flow,we can use the homogenous temperature of the FIA of the coarse calcite to date the forma-tion and the destruction time of the Majiang ancient oil reservoir.Episodic fluid flow was known for its inhomogeneous trapping,which resulted in the failure of dating according to the burial history.But taking a close look at its temperature variation,we think that the latest stage of fluid flow,characterized by steady state temperature and grow of the coarser crystals,can be used for dating.It will be of great value if this method is proved to be effective.The formation and the destruction time of the Majiang ancient oil reservoir were dated to be in the Indosinian Period and the late Yanshan-early Hymalayan Period respectively.This conclusion is in great discrepancy with the common accepted idea that the Majiang ancient oil reservoir was formed and destroyed during the Caledonian tectonic movement.Even so,this paper further discussed its reliability from the view of the source rock evolution and also the local tectonic evolution.展开更多
基金Special and Significant Project of National Science and Technology“Development of Large Oil/gas Fields and Coalbed Methane”(No.2011ZX05004-001).
文摘Deep marine carbonate rocks have become one of the key targets of onshore oil and gas exploration and development for reserves replacement in China.Further geological researches of such rocks may practically facilitate the sustainable,steady and smooth development of the petroleum industry in the country.Therefore,through a deep investigation into the fundamental geological conditions of deep marine carbonate reservoirs,we found higher-than-expected resource potential therein,which may uncover large oil or gas fields.The findings were reflected in four aspects.Firstly,there are two kinds of hydrocarbon kitchens which were respectively formed by conventional source rocks and liquid hydrocarbons cracking that were detained in source rocks,and both of them can provide large-scale hydrocarbons.Secondly,as controlled by the bedding and interstratal karstification,as well as the burial and hydrothermal dolomitization,effective carbonate reservoirs may be extensively developed in the deep and ultra-deep strata.Thirdly,under the coupling action of progressive burial and annealing heating,some marine source rocks could form hydrocarbon accumulations spanning important tectonic phases,and large quantity of liquid hydrocarbons could be kept in late stage,contributing to rich oil and gas in such deep marine strata.Fourthly,large-scale uplifts were formed by the stacking of multi-episodic tectonism and oil and gas could be accumulated in three modes(i.e.,stratoid large-area reservoir-forming mode of karst reservoirs in the slope area of uplift,back-flow type large-area reservoir-forming mode of buried hill weathered crust karst reservoirs,and wide-range reservoir-forming mode of reef-shoal reservoirs);groups of stratigraphic and lithologic traps were widely developed in the areas of periclinal structures of paleohighs and continental margins.In conclusion,deep marine carbonate strata in China onshore contain the conditions for widely and intensively preserving hydrocarbons,so large oil or gas fields are expected.
基金supported by the Science and Technology Cooperation Project of the CNPC-SWPU Innovation Alliance(No.2020CX010501).
文摘In view of the characteristics of deep marine carbonate reservoirs in the Sichuan Basin,such as a deep burial depth(5000-8120 m),high temperatures(150℃-180℃),a large inclination toward wells,and large acid-rock reaction rate,a high-temperature gelled acid and a preflush containing a self-generating acid that matched with the high-temperature gelled acid were developed.The results of laboratory evaluation showed that the viscosity of the high-temperature gelled acid at 180℃ was 30 mPa·s,with a corrosion rate lower than 70 g/m^(2)·h.The drag reduction and acid-rock reaction rates reached 64%-71% and 1.569×10^(-4) mol/cm^(2)·s respectively,demonstrating obvious retarding performance.In addition,the viscosity of the preflush containing a self-generating acid(after shearing at 160℃ for 1 h)remained at 200 mPa·s.Compared with a full injection of the high-temperature gelled acid,the acid-etched fracture conductivity after an alternate injection of the preflush containing self-generating and high-temperature gelled acids increased by more than 50%.Field application showed that the hightemperature gelled acid played a vital role in connecting fractures where as the preflush containing self-generating acid demonstrated an outstanding fracture-formation ability.After a three-stage alternate injection(a preflush containing self-generating and gelled acids),a remarkable stimulation effect was achieved for increase natural gas production.
文摘A series of significant discoveries in marine carbonate rocks show great petroleum exploration potential in the Tarim Basin. However, the oil and gas fields discovered in the carbonate rocks are mainly distributed around the Manjiaer Sag in the eastern Tarim Basin. Some explorations occurred and no oil or gas field was discovered around the Awati Sag in the western Tarim Basin. Information from wells and outcrops reveals that there are excellent oil and gas source rock conditions around the Awati Sag. Transformed reef-shoal reservoirs could be formed in the Ordovician carbonate rocks with paleo-geographic background and hydrothermal conditions. Therefore, it is necessary to make a systematical study and overall evaluation of the potential of the periphery of the Awati Sag in terms of source rock evolution, resource potential, high-grade reservoir formation and distribution, and main factors controlling hydrocarbon migration and accumulation.
基金Project supported by the National Major Science and Technology Project“Demonstration Project of Development of Large Carbonate Gas Fields in the Sichuan Basin”(No.:2016ZX05052)Scientific Research and Technological Development Project of PetroChina Company Limited“Research and Application of Key Technologies for 30 Bcm-level Gas Production in the Southwest Oil&Gas Field”(No.:2016E-06).
文摘In recent years,deep marine carbonate gas reservoirs have become an important field in increasing conventional gas reserves and production in the Sichuan Basin.Due to complex hydrocarbon accumulation conditions,great burial depth and complicate gas-water relation,however,this type of gas reservoirs faces huge challenges to realize efficient development.In this paper,the development history of deep marine carbonate gas reservoirs in the Sichuan Basin was analyzed.Then,based on such development characteristics and practices,special technologies were summarized.Finally,the research direction for the coming years was pointed out.And the following research results were obtained.First,the reserves of the deep marine carbonate gas reservoirs in the Sichuan Basin vary greatly in scales and types.The reservoirs are of poor quality and strong heterogeneity with active edge and bottom water.The raw gas generally contains acidic gas.What's more,most development wells are located in mountainous areas,and drilled formations are complicated in vertical distribution.Second,special technologies have been formed in the Sichuan Basin,including the fine description technology for strong-heterogeneity gas reservoirs in deep low-gentle structures,the optimized water control technology for the water-bearing gas reservoirs with developed small-scale fractures and vugs,drilling,completion and stimulation engineering technologies for deep complex gas wells,and the support technology for clean and safe development of sulfur-bearing gas reservoirs,so as to provide support for the efficient productivity construction and optimized development of giant marine carbonate reservoirs in the Sichuan Basin.Third,as the development of the carbonate gas reservoirs in the Sichuan Basin begins to convert into the gas reservoirs in ultra-deep complex structures,the next direction of technological research is the fine structure description and thin reservoir prediction technique,across-scale numerical simulation technique,drilling and completion and gas production engineering technique for deep marine carbonate gas reservoirs.It is concluded that these special technologies for the efficient development of deep marine carbonate gas reservoirs provides powerful support for PetroChina Southwest Company to build up giant gas fields with the reserves of tens of billions of cubic meters and realize the leaping growth of gas production.The research results can provide valuable technical reference for the development of deep marine carbonate gas reservoirs at home and abroad.
基金sponsored by the National Key Basic Research Program of China (973 Program, 2012CB214806)the National Natural Science Foundation of China (No. 41372144)
文摘There are rich oil and gas resources in marine carbonate strata worldwide.Although most of the oil and gas reserves discovered so far are mainly distributed in Mesozoic,Cenozoic,and upper Paleozoic strata,oil and gas exploration in the Proterozoic–Lower Paleozoic（PLP）strata—the oldest marine strata—has been very limited.To more clearly understand the oil and gas formation conditions and distributions in the PLP marine carbonate strata,we analyzed and characterized the petroleum geological conditions,oil and gas reservoir types,and their distributions in thirteen giant oil and gas fields worldwide.This study reveals the main factors controlling their formation and distribution.Our analyses show that the source rocks for these giant oil and gas fields are mainly shale with a great abundance of type I–II organic matter and a high thermal evolution extent.The reservoirs are mainly gas reservoirs,and the reservoir rocks are dominated by dolomite.The reservoir types are mainly karst and reef–shoal bodies with well-developed dissolved pores and cavities,intercrystalline pores,and fractures.These reservoirs arehighly heterogeneous.The burial depth of the reservoirs is highly variable and somewhat negatively correlated to the porosity.The cap rocks are mainly thick evaporites and shales,with the thickness of the cap rocks positively correlated to the oil and gas reserves.The development of high-quality evaporite cap rock is highly favorable for oil and gas preservation.We identified four hydrocarbon generation models,and that the major source rocks have undergone a long period of burial and thermal evolution and are characterized by early and long periods of hydrocarbon generation.These giant oil and gas fields have diverse types of reservoirs and are mainly distributed in paleo-uplifts,slope zones,and platform margin reef-shoal bodies.The main factors that control their formation and distribution were identified,enabling the prediction of new favorable areas for oil and gas exploration.
基金supported by the National Natural Science Foundation of China"Research on acidizing mechanism under the coupling of temperature,fracture flow,acid-rock reaction,and stress damage for fractured carbonate rocks"(No.51704249)National Natural Science Foundation of China"Acid fracturing of low-permeability and tight oil and gas reservoirs"(No.51525404)the China Postdoctoral Science Foundation-General Program Research on acidizing mechanism of fracture network in deep,high-temperature,fractured carbonat rocks"(No.2017M623063).
文摘Acid fracturing is an indispensable technology in the efficient development of carbonate oil and gas rosarvoirs.As for deep and ultra-deep marine carbonate oil and gas reservoirs,however,existing acid fracturing technologies can hardly create complex fracture networks because of their particular engineering and geological characteristics.In order to realize the efficient three-dimensional development of deep and ultra-deep marine carbonate oil and gas reservoirs,this paper revealed the acid fracturing difficulties of this kind of reservoirs based on the engineering and geological characteristics of deep marine carbonate oil and gas reservoirs in China.Then,by taking the efficient three-dimensional development of deep and ultra-deep marine carbonate oiland gas reservoirs as the target,the technical conceptof three-dimensional acid fracturing(3D-AF)was putforward based on the techniques of volume acid fracturing and deep acid fracturing.In addition,its technical connotation was il lustrated,and its key technologies were described in detail.Finally,its development direction in the next step was pointed out.And the following research results were obtained.First,the 3D-AF technology contains three basic connotations:(1)selecting the corresponding acid penetration technology according to reservoir types so as to realize sufficient resarvoir stimulation on the plane;(2)creating complex acid-fracture volume with higher flow conductivity under high closed pressure;(3)deploying acid-fracture volume rationally along the long hole section so as to realize sufficient reservoir stimulation in the wellbore direction.Second,there are three key technologies of 3D-AF,i.e.,the technology for predicting the effective acid-penetrate distance under the coupling action of multi-feld,multi-scale and multi-fluid,the technology for optimizing the flow conductivity of complex acid-fracture volume,and the technology for precisely deploying acid in the long section of horizontal well or highly deviated well.Third,in order to promote the further development of 3D-AFtechnology,it is necessary to carry out researches on three technologies,i.e.,the technology for predicting and reducing the fracturing pressure of ultra-deep reservoir,the tech-nology for predicting the geometry of acid-fracture body ina strongly heterogeneous reservoir,and the staged reservoir production technology and new fluid technology with high temperature resistance,low reaction rate and low friction resistance coefficient for long hole sections(over 7000 m).
基金Supported by the Sichuan Province Regional Innovation Cooperation Project(21QYCX0048)Sinopec Science and Technology Department Project(P21048-3)。
文摘According to the complex differential accumulation history of deep marine oil and gas in superimposed basins,the Lower Paleozoic petroleum system in Tahe Oilfield of Tarim Basin is selected as a typical case,and the process of hydrocarbon generation and expulsion,migration and accumulation,adjustment and transformation of deep oil and gas is restored by means of reservoine-forming dynamics simulation.The thermal evolution history of the Lower Cambrian source rocks in Tahe Oilfield reflects the obvious differences in hydrocarbon generation and expulsion process and intensity in different tectonic zones,which is the main reason controlling the differences in deep oil and gas phases.The complex transport system composed of strike-slip fault and unconformity,etc.controlled early migration and accumulation and late adjustment of deep oil and gas,while the Middle Cambrian gypsum-salt rock in inner carbonate platform prevented vertical migration and accumulation of deep oil and gas,resulting in an obvious"fault-controlled"feature of deep oil and gas,in which the low potential area superimposed by the NE-strike-slip fault zone and deep oil and gas migration was conducive to accumulation,and it is mainly beaded along the strike-slip fault zone in the northeast direction.The dynamic simulation of reservoir formation reveals that the spatio-temporal configuration of"source-fault-fracture-gypsum-preservation"controls the differential accumulation of deep oil and gas in Tahe Oilfield.The Ordovician has experienced the accumulation history of multiple periods of charging,vertical migration and accumulation,and lateral adjustment and transformation,and deep oil and gas have always been in the dynamic equilibrium of migration,accumulation and escape.The statistics of residual oil and gas show that the deep stratum of Tahe Oilfield still has exploration and development potential in the Ordovician Yingshan Formation and Penglaiba Formation,and the Middle and Upper Cambrian ultra-deep stratum has a certain oil and gas resource prospect.This study provides a reference for the dynamic quantitative evaluation of deep oil and gas in the Tarim Basin,and also provides a reference for the study of reservoir formation and evolution in carbonate reservoir of paleo-craton basin.
基金Project supported by the National Major S&T Project(Grant No.2011ZX05004&2011ZX05003-004)the National Natural Science Fund Project(Grant No.41472103).
文摘Various types of paleo-uplifts with different characteristics are developed in the Tarim Basin.Previously,there were multiple opinions on the pale-uplifts origins and structural evolution,so the oil and gas exploration ideas and deployment in the Tarim Basin were not developed smoothly.In this paper,regional seismic interpretation and structural analysis were carried out on the deep marine carbonate rocks in this basin based on the new seismic and drilling data.Then combined with the structural denudation results,the paleo-structural frameworks were reconstructed.And finally,the formation stage and main controlling factors of paleo-uplifts were discussed.It is shown that the Middle Ordovician is the key period when regional extension was converted to compression in this basin,so stratigraphic,sedimentary and structural differences occurred.Before the deposition of Yijianfang Fm in late Middle Ordovician,three carbonate paleo-uplifts(i.e.,the Northern,Central and SW Tarim paleo-uplifts)begun to appear,and they were all broad-folded paleo-uplifts of nearly E-W striking and were formed at the same stage.The distribution and development of the Phanerozoic uplifts in this basin are restricted by the Northern and Southern Tarim basement paleuplifts of nearly E-W striking which were developed during the Precambrian.It is indicated that all the three paleo-uplifts are compressional paleo-uplifts originated from the convergence of the southern plate margin based on the basement paleo-uplifts and they are all characterized by similar structural characteristics and inherited formation and evolution.The current differences of paleo-uplifts are controlled by multi-stage intense structural reformation since the Silurian.It is concluded that the oil and gas exploration potential is immense in the carbonate reservoirs of well-preserved deep paleo-structural zones in a larger area.
基金funded by the Strategic Priority Research Program of the Chinese Academy of Sciences,Grant No.XDA14010302the National Science Foundation of China(41772145,42172179 and 41772146).
文摘The exploration of deep layers has become increasingly important in the global oil and gas industry.The Tazhong-Bachu area of the Tarim Basin is a pioneering target for deep petroleum exploration in China,but only Wells Zhongshen1 and Zhongshen5 have found industrial oil flow in the Cambrian.Noteworthily,the occurrence of reservoir bitumen in the Lower Cambrian coring interval in many wells indicates that large-scale hydrocarbon migration had occurred here in geological history.Effective identification of reservoir bitumen in the Cambrian dolomite reservoirs is crucial to understanding hydrocarbons'distribution and migration.In this study,we adopt the Reservoir Bitumen Index(RBI)method to deduce a quantitative calculation formula for reservoir bitumen,and classify the transport system into four types based on differences in hydrocarbon transport behavior and characteristics.The results show that the deep carbonate low permeability-tight reservoirs of the Lower Cambrian in the Tazhong-Bachu area generally develop reservoir bitumen,most likely derived from underlying Precambrian source rocks.Therefore,the Lower Cambrian carbonate reservoir is considered a near-source discrete petroleum transport system,providing great potential for further oil and gas exploration in the Lower Paleozoic in the Tazhong-Bachu area.
基金Supported by National Basic Research Program of China(Grant No.2006CB202308,2005CB422107)National Natural Science Foundation of China(Grant No.40472078)
文摘Combined evidence from the outcrop and the fluid inclusion assemblage(FIA)analysis indicates that there exist two episodes of fluid flow controlled by the tectonic activity.The first episode was recorded mainly in the reservoir rock of the Honghuayuan Formation,representing the fluid flow of hydrocarbon charging.The second episode occurred mainly along the fault systems,representing the fluid move-ment when the ancient oil reservoir was destroyed.The host mineral morphology,homogeneous tem-perature,and salinity of the FIAs record an episodic fluid movement.Characters of high homogenous temperature,low salinity and a quick temperature variation of the first episode fluid flow may indicate an early-stage fluid eruption,and correspondingly,fine-grained calcite was formed.Temperature of the erupted fluid tended to decrease during its mixing with the upper formation fluid and finally had the same temperature as the upper formation.From then on,the temperature was rather steady and fa-vored the growth of the coarse calcite.Due to this character of the temperature variation of the episodic fluid flow,we can use the homogenous temperature of the FIA of the coarse calcite to date the forma-tion and the destruction time of the Majiang ancient oil reservoir.Episodic fluid flow was known for its inhomogeneous trapping,which resulted in the failure of dating according to the burial history.But taking a close look at its temperature variation,we think that the latest stage of fluid flow,characterized by steady state temperature and grow of the coarser crystals,can be used for dating.It will be of great value if this method is proved to be effective.The formation and the destruction time of the Majiang ancient oil reservoir were dated to be in the Indosinian Period and the late Yanshan-early Hymalayan Period respectively.This conclusion is in great discrepancy with the common accepted idea that the Majiang ancient oil reservoir was formed and destroyed during the Caledonian tectonic movement.Even so,this paper further discussed its reliability from the view of the source rock evolution and also the local tectonic evolution.
