Shale oil reservoirs are generally characterized by complex mineral compositions, rapid lithofacies changes, and thin laminae. Explorations have confirmed that the type and density of shale laminae significantly influ...Shale oil reservoirs are generally characterized by complex mineral compositions, rapid lithofacies changes, and thin laminae. Explorations have confirmed that the type and density of shale laminae significantly influence reservoir quality, highlighting the importance of accurately identifying these laminae through well logging for effective shale reservoir evaluation. Presently, relevant technologies primarily focus on the qualitative identification of shale laminae using vertical slab images from image logs. However, influenced by the complex borehole conditions and image logging quality, this approach is less effective in identifying millimeter-scale laminae. This study proposes a new method for achieving high-resolution slab images and quantitatively evaluating the laminae using electrical image logs. The new method effectively improves the processing accuracy of slab images by delicately flattening and aligning the button electrode curves derived from electrical image logs point by point. Meanwhile, it allows for the accurate quantitative evaluation of the lamina number through precise identification of peaks and troughs in microelectrode curves. As demonstrated by the applications in shale oil reservoirs in the Gulong area in Daqing and the Ganchagou area in Qinghai, the proposed method can significantly improve accuracy compared to traditional slab images. Furthermore, the lamination index calculated using this method is highly consistent with the lamina number observed in cores. This study provides a new technical method for the quantitative lamina evaluation and rock structure analysis of shale reservoirs.展开更多
Fine-grained sedimentary rocks have become a research focus as important reservoirs and source rocks for tight and shale oil and gas.Laminae development determines the accumulation and production of tight and shale oi...Fine-grained sedimentary rocks have become a research focus as important reservoirs and source rocks for tight and shale oil and gas.Laminae development determines the accumulation and production of tight and shale oil and gas in fine-grained rocks.However,due to the resolution limit of conventional logs,it is challenging to recognize the features of centimeter-scale laminae.To close this gap,complementary studies,including core observation,thin section,X-ray diffraction(XRD),conventional log analysis,and slabs of image logs,were conducted to unravel the centimeter-scale laminae.The laminae recognition models were built using well logs.The fine-grained rocks can be divided into laminated rocks(lamina thickness of<0.01 m),layered rocks(0.01-0.1 m),and massive rocks(no layer or layer spacing of>0.1 m)according to the laminae scale from core observations.According to the mineral superposition assemblages from thin-section observations,the laminated rocks can be further divided into binary,ternary,and multiple structures.The typical mineral components,slabs,and T2spectrum distributions of various lamina types are unraveled.The core can identify the centimeter-millimeter-scale laminae,and the thin section can identify the millimeter-micrometer-scale laminae.Furthermore,they can detect mineral types and their superposition sequence.Conventional logs can identify the meter-scale layers,whereas image logs and related slabs can identify the laminae variations at millimeter-centimeter scales.Therefore,the slab of image logs combined with thin sections can identify laminae assemblage characteristics,including the thickness and vertical assemblage.The identification and classification of lamina structure of various scales on a single well can be predicted using conventional logs,image logs,and slabs combined with thin sections.The layered rocks have better reservoir quality and oil-bearing potential than the massive and laminated rocks.The laminated rocks’binary lamina is better than the ternary and multiple layers due to the high content of felsic minerals.The abovementioned results build the prediction model for multiscale laminae structure using well logs,helping sweet spots prediction in the Permian Lucaogou Formation in the Jimusar Sag and fine-grained sedimentary rocks worldwide.展开更多
The Chang 73 sub-member of Triassic Yanchang Formation in the Ordos Basin was taken as an example and the lamina types and combinations,reservoir space features and shale oil enrichment patterns in organic-rich shale ...The Chang 73 sub-member of Triassic Yanchang Formation in the Ordos Basin was taken as an example and the lamina types and combinations,reservoir space features and shale oil enrichment patterns in organic-rich shale strata were investigated using core observation,thin section analysis,XRF element measurement,XRD analysis,SEM,high solution laser Raman spectroscopy analysis,and micro-FTIR spectroscopy analysis,etc.According to the mineral composition and thickness of the laminae,the Chang 73 organic-rich shales have four major types of laminae,tuff-rich lamina,organic-rich lamina,silt-grade feldspar-quartz lamina and clay lamina.They have two kinds of shale oil-bearing layers,"organic-rich lamina+silt-grade feldspar-quartz lamina"and"organic-rich lamina+tuff-rich lamina"layers.In the"organic-rich+silt-grade feldspar-quartz"laminae combination shale strata,oil was characterized by relative high maturation,and always filled in K-feldspar dissolution pores in the silt-grade feldspar-quartz laminae,forming oil generation,migration and accumulation process between laminae inside the organic shales.In the"organic-rich+tuff-rich lamina"binary laminae combination shale strata,however,the reservoir properties were poor in organic-rich shales,the oil maturation was relatively lower,and mainly accumulated in the intergranular pores of interbedded thin-layered sandstones.The oil generation,migration and accumulation mainly occurred between organic-rich shales and interbedded thin-layered sandstones.展开更多
Novel fully biodegradable thermoplastic composite laminates reinforced with ultrathin wood laminae were prepared through a hot-pressing process by using two different thermoplastic starch(TPS)matrices.The microstructu...Novel fully biodegradable thermoplastic composite laminates reinforced with ultrathin wood laminae were prepared through a hot-pressing process by using two different thermoplastic starch(TPS)matrices.The microstructure and physical properties of the resulting unidirectional and bidirectional laminates were studied.The investigated materials presented a complex microstructure,in which the porosity of the wood laminae was almost entirely occluded by the polymer matrix.The mechanical behavior of the laminates was strongly affected by the obtained microstructure,and matrix penetration in wood pores led to biodegradable composites with elastic modulus and tensile strength higher than those of their constituents.Finally,thermal welding and thermoformability tests proved how these materials possess features typical of thermoplastic materials.展开更多
Based on thin-section,argon-ion polished large-area imaging and nano-CT scanning data,the reservoir characteristics and genetic mechanisms of the Lower Silurian Longmaxi shale layers with different laminae and laminae...Based on thin-section,argon-ion polished large-area imaging and nano-CT scanning data,the reservoir characteristics and genetic mechanisms of the Lower Silurian Longmaxi shale layers with different laminae and laminae combinations in the Sichuan Basin were examined.It is found that the shale has two kinds of laminae,clayey lamina and silty lamina,which are different in single lamina thickness,composition,pore type and structure,plane porosity and pore size distribution.The clayey laminae are about 100μm thick each,over 15%in organic matter content,over 70%in quartz content,and higher in organic pore ratio and plane porosity.They have abundant bedding fractures and organic matter and organic pores connecting with each other to form a network.In contrast,the silty laminae are about 50μm thick each,5%to 15%in organic matter content,over 50%in carbonate content,higher in inorganic pore ratio,undeveloped in bedding fracture,and have organic matter and organic pores disconnected from each other.The formation of mud lamina and silt lamina may be related to the flourish of silicon-rich organisms.The mud lamina is formed during the intermittent period,and silt lamina is formed during the bloom period of silicon-rich organisms.The mud laminae and silt laminae can combine into three types of assemblages:strip-shaped silt,gradating sand-mud and sand-mud thin interlayers.The strip-shaped silt assemblage has the highest porosity and horizontal/vertical permeability ratio,followed by the gradating sand-mud assemblage and sand-mud thin interlayer assemblage.The difference in the content ratio of the mud laminae to silt laminae results in the difference in the horizontal/vertical permeability ratio.展开更多
Based on various test data, the composition, texture, structure and lamina types of gas-bearing shale were determined based on Well Wuxi 2 of the Silurian Longmaxi Formation in the Sichuan Basin. Four types of lamina,...Based on various test data, the composition, texture, structure and lamina types of gas-bearing shale were determined based on Well Wuxi 2 of the Silurian Longmaxi Formation in the Sichuan Basin. Four types of lamina, namely organic-rich lamina, organic-bearing lamina, clay lamina and silty lamina, are developed in the Longmaxi Formation of Well Wuxi 2, and they form 2 kinds of lamina set and 5 kinds of beds. Because of increasing supply of terrigenous clasts and enhancing hydrodynamics and associated oxygen levels, the contents of TOC and brittle mineral reduce and content of clay mineral increases gradually as the depth becomes shallow. Organic-rich lamina, organic-rich + organic-bearing lamina set and organic-rich bed dominate the small layers 1-3 of Member 1 of the Longmaxi Formation, suggesting anoxic and weak hydraulic depositional setting. Organic-rich lamina, along with organic-bearing lamina and silty lamina, appear in small layer 4, suggesting increased oxygenated and hydraulic level. Small layers 1-3 are the best interval and drilling target of shale gas exploration and development.展开更多
In this study,an in-depth analysis of the types,characteristics,and formation mechanisms of microlaminae and microscopic laminae was conducted in order to precisely examine the link or intersection of stratigraphy and...In this study,an in-depth analysis of the types,characteristics,and formation mechanisms of microlaminae and microscopic laminae was conducted in order to precisely examine the link or intersection of stratigraphy and petrology.This study was essentially a sedimentary examination of the minuteness-macro and micro-tiny layers between laminae and pore structure,as well as the types of structures and sedimentation.The results of this study bear important basic subject attributes and significance,as well as practical value for the basic theories and exploration applications of unconventional oil and gas geology.The quantitative data were obtained using the following:field macroscopic observations;measurements;intensive sampling processes;XRD mineral content analysis;scanning electron microscopy;high-power polarizing microscope observations;and micro-scale measurements.The quantitative parameters,such as laminae thicknesses,laminae properties,organic matter laminae,and laminae spatial distributions were unified within a framework,and the correlations among them were established for the purpose of forming a fine-grained deposition micro-laminae evaluation system.The results obtained in this research investigation established a basis for the classification of micro-laminae,and divided the micro-laminae into four categories and 20 sub-categories according to the development thicknesses,material compositions,organic matter content levels,and the spatial distributions of the micro-laminae.The classification scheme of the micro-laminae was divided into two categories and 12 sub-categories.Then,in accordance with the comprehensive characteristics of spatial morphology,the micro-laminae was further divided into the following categories:continuous horizontal laminae;near horizontal laminae;slow wavy laminae;wavy laminae;discontinuous laminae;and lenticular laminae.According to the structural properties of the laminae development,the micro-laminae was divided into the following categories:single laminae structures;laminated laminae structures;interlaminar structures;multiple mixed laminae structures;cyclic laminae structures;and progressive laminae structures.The research results were considered to be applicable for the scientific evaluations of reservoir spaces related to unconventional oil and gas resources.展开更多
China's lacustrine shale oil reserves are abundant,making it a key area for future exploration and development.Most lacustrine shales feature a mix of mineral compositions and interlayer sedimentary structures.Hig...China's lacustrine shale oil reserves are abundant,making it a key area for future exploration and development.Most lacustrine shales feature a mix of mineral compositions and interlayer sedimentary structures.High-quality reservoirs exhibit significant heterogeneity,which influences the stress distribution during fracturing,leading to complex fracture network patterns.This complexity presents challenges for the comprehensive well logging evaluation of the geological-engineering"double sweet spots"in shale oil,severely restricting efficient development.This study focuses on the impact of shale sedimentary layering on the radial slowness of dipole shear waves.It employs rock physics experiments combined with advanced well logging techniques to explore the relationship between reservoir anisotropy caused by sedimentary layering and reservoir quality,thereby establishing a logging evaluation method for vertical identification of"sweet spots"in lacustrine shale oil.The shales in the Fengcheng Formation of the Mahu Sag into three types according to sedimentary structure scale:laminated,interlayer,and massive.Each type has different mineral compositions,affecting reservoir quality and fracturing potential.Laminated shales develop more fractures under stress along the beddings,showing moderate anisotropy,with reservoir capacity dependent on intercrystalline porosity within carbonate layers.Interlayer shales easily form complex fracture networks,exhibiting significant anisotropy,and their reservoir capacity depends on the porosity within sandy bands.Massive mudstones have the fewest fractures under stress,appearing isotropic with reservoir capacity dependent on matrix pore size.The intensity of reservoir anisotropy correlates positively with storage capacity and the propensity to form irregular and complex fracture networks during hydraulic fracturing.In sections without natural fractures,a larger difference between fast and slow shear waves corresponds to a radial profile shift towards warm tones,indicating stronger anisotropy and better reservoir quality,thus forming complex fracture networks during fracturing.Conversely,a smaller difference leads to a profile energy shift towards cooler tones,indicating stronger isotropy and poorer reservoir quality,hindering the formation of complex fracture networks during hydraulic fracturing.In sections with natural fractures,the difference between fast and slow shear waves exhibits erratic behavior,showing a cross-pattern in radial profiles,indicating strong anisotropy.The presence of natural fractures can synergize with induced fracture networks to form more complex systems,significantly enhancing reservoir productivity.展开更多
Gene expression is regulated by chromatin architecture and epigenetic remodeling in cell homeostasis and pathologies.Histone modifications act as the key factors to modulate the chromatin accessibility.Different histo...Gene expression is regulated by chromatin architecture and epigenetic remodeling in cell homeostasis and pathologies.Histone modifications act as the key factors to modulate the chromatin accessibility.Different histone modifications are strongly associated with the localization of chromatin.Heterochromatin primarily localizes at the nuclear periphery,where it interacts with lamina proteins to suppress gene expression.In this review,we summarize the potential bridges that have regulatory functions of histone modifications in chromatin organization and transcriptional regulation at the nuclear periphery.We use lamina-associated domains(LADs)as examples to elucidate the biological roles of the interactions between histone modifications and nuclear lamina in cell differentiation and development.In the end,we highlight the technologies that are currently used to identify and visualize histone modifications and LADs,which could provide spatiotemporal information for understanding their regulatory functions in gene expression and discovering new targets for diseases.展开更多
AIM:To propose a novel glaucoma surgery for rebalancing translaminar pressure difference.METHODS:Three non-human primates with normal eyes and two with laser-induced glaucoma underwent the novel surgical procedure.Can...AIM:To propose a novel glaucoma surgery for rebalancing translaminar pressure difference.METHODS:Three non-human primates with normal eyes and two with laser-induced glaucoma underwent the novel surgical procedure.Cannulation of the subarachnoid space was performed after completion of routine vitrectomy steps.An XEN 45 implant was inserted into the created puncture to communicate between the vitreous body and subarachnoid space.Intraocular pressure(IOP),fundus photography,and spectral-domain optical coherence tomography were assessed at baseline and regular intervals during follow-up.RESULTS:All operated eyes showed IOP reduction in the first postoperative month.Two(2/3)normal eyes and one(1/2)glaucomatous eye maintained lower IOP until 18mo after operation.The XEN 45 implant remained positioned through the lamina cribrosa in all normal eyes but was not detected in two glaucomatous eyes.Complications observed in this study included retinal vascular bleeding in 1/3 normal eyes and XEN implant dislocation in all 2 glaucomatous eyes.CONCLUSION:Subarachnoid space cannulation and mini-shunt implantation may contribute to IOP reduction,possibly by rebalancing translaminar pressure difference and enhancing aqueous humor drainage.The development of a suitable mini-shunt requires further investigation.展开更多
The lamina(combination)types,reservoir characteristics and shale oil occurrence states of organic-rich shale in the Triassic Yanchang Formation Chang 73 sub-member in the Ordos Basin were systematically investigated t...The lamina(combination)types,reservoir characteristics and shale oil occurrence states of organic-rich shale in the Triassic Yanchang Formation Chang 73 sub-member in the Ordos Basin were systematically investigated to reveal the main controlling factors of shale oil occurrence under different lamina combinations.The differential enrichment mechanisms and patterns of shale oil were discussed using the shale oil micro-migration characterization and evaluation methods from the perspectives of relay hydrocarbon supply,stepwise migration,and multi-stage differentiation.The results are obtained in five aspects.First,Chang 73 shale mainly develops five types of lamina combination,i.e.non-laminated shale,sandy laminated shale,tuffaceous laminated shale,mixed laminated shale,and organic-rich laminated shale.Second,shales with different lamina combinations are obviously different in the reservoir space.Specifically,shales with sandy laminae and tuffaceous laminae have a large number of intergranular pores,dissolution pores and hydrocarbon generation-induced fractures.The multi-scale pore and fracture system constitutes the main place for liquid hydrocarbon occurrence.Third,the occurrence and distribution of shale oil in shale with different lamina combinations are jointly controlled by organic matter abundance,reservoir property,thermal evolution degree,mineral composition and laminae scale.The micro-nano-scale pore-fracture networks within shales containing rigid laminae,particularly sandy and tuffaceous laminations,primarily contain free-state light hydrocarbon components.In contrast,adsorption-phase heavy hydrocarbon components predominantly occupy surfaces of organic matter assemblages,clay mineral matrices,and framework mineral particulates.Fourth,there is obvious shale oil micro-migration between shales with different lamina combinations in Chang 73.Generally,such micro-migration is stepwise in a sequence of organic-rich laminated shale→tuffaceous laminated shale→mixed laminated shale→sandy lamiated shale→non-laminated shale.Fifth,the relay hydrocarbon supply of organic matter under the control of the spatial superposition of shales with various laminae,the stepwise migration via multi-scale pore and fracture network,and the multi-differentiation in shales with different lamina combinations under the control of organic-inorganic interactions fundamentally decide the differences of shale oil components between shales with different lamina combinations.展开更多
Abnormal accumulation of collagen fibrils is a hallmark feature of oral submucous fibrosis(OSF).However,the precise characteristics and underlying mechanisms remain unclear,impeding the advancement of potential therap...Abnormal accumulation of collagen fibrils is a hallmark feature of oral submucous fibrosis(OSF).However,the precise characteristics and underlying mechanisms remain unclear,impeding the advancement of potential therapeutic approaches.Here,we observed that collagen Ⅰ,the main component of the extracellular matrix,first accumulated in the lamina propria and subsequently in the submucosa of OSF specimens as the disease progressed.Using RNA-seq and Immunofluorescence in OSF specimens,we screened the cartilage oligomeric matrix protein(COMP)responsible for the abnormal collagen accumulation.Genetic COMP deficiency reduced arecoline-stimulated collagen I deposition significantly in vivo.In comparison,both COMP and collagen Ⅰ were upregulated under arecoline stimulation in wild-type mice.Human oral buccal mucosal fibroblasts(hBMFs)also exhibited increased secretion of COMP and collagen I after stimulation in vitro.COMP knockdown in hBMFs downregulates arecoline-stimulated collagen Ⅰ secretion.We further demonstrated that hBMFs present heterogeneous responses to arecoline stimulation,of which COMP-positive fibroblasts secrete more collagen Ⅰ.Since COMP is a molecular bridge with Fibril-associated collagens with Interrupted Triple helices(FACIT)in the collagen network,we further screened and identified collagen XIV,a FACIT member,co-localizing with both COMP and collagen Ⅰ.Collagen XIV expression increased under arecoline stimulation in wild-type mice,whereas it was hardly expressed in the Comp^(-/-) mice,even with under stimulation.In summary,we found that COMP may mediates abnormal collagen Ⅰ deposition by functions with collagen XIV during the progression of OSF,suggesting its potential to be targeted in treating OSF.展开更多
The annual laminae gray level variations in the stalagmite TS9501 of Shihua Cave, Beijing are studied in detail. The environmental factors influencing the laminae gray level are also analyzed. The following conditions...The annual laminae gray level variations in the stalagmite TS9501 of Shihua Cave, Beijing are studied in detail. The environmental factors influencing the laminae gray level are also analyzed. The following conditions may be necessary to the study on the lamina gray level. A) The seasonal differences of climate in the studied area are strong. B) The cave has a rapid and simple hydrological connection with the surface, such that the gray level variation is great; therefore, climatic changes can be more clearly recorded in a stalagmite. C) No water from other sources due to lateral flow adds to the seepage over the cave. D) There are more organic impurities than inorganic ones, whose content changes distinctly with time in the sample. By comparison with the modern instrumental climate records, it was found that the gray level of laminae is mainly related to the air temperature, especially the summer mean temperature. Therefore, the gray level can be used as a proxy of the air temperature. The variation of the lamina gray level also represents the oscillation of Indian summer monsoon as identified in the modern climate records. The variability of the temperature in Beijing area over the last 1 ka is reconstructed. The results show that there are several cold periods corresponding to historical records. An important phenomenon is noticed that the climatic pattern before about 1400AD is different from that after about 1400AD. In Beijing area, before about 1400AD, low amplitude and high frequency temperature oscillations dominated the signal. The climate pattern is warm-dry and cold-wet. After about 1400AD, both the temperature and rainfall varied synchronously, temperature oscillated strongly and the Little Ice Age occurred. The climate pattern is cold-dry and warm-wet. This transition of the climate pattern is also observed in other worldwide paleoclimatic records, demonstrating that there was a global climate event at about 1400AD.展开更多
The mechanism of SC-CO_(2)-brine-rock interaction(SCBRI) and its effect on the mechanical properties of shale are crucial for shale oil development and CO_(2)sequestration. To clarify the influence of SCBRI on the mic...The mechanism of SC-CO_(2)-brine-rock interaction(SCBRI) and its effect on the mechanical properties of shale are crucial for shale oil development and CO_(2)sequestration. To clarify the influence of SCBRI on the micromechanics of shale, the lamina and matrix of shale were saturated with SC-CO_(2)-brine for 2, 4, 6,and 8 days, respectively. The micro-scratch technique was then used to measure the localized fracture toughness before and after SC-CO_(2)-brine saturation. Combining the micro-scratch results with SEM-QEMSCAN-EDS analysis, the differences in mineral composition and mechanical properties of lamina(primarily composed of carbonate minerals) and matrix(primarily composed of clay minerals) were studied. The QEMSCAN analysis and micro-scratch results indicate distinct mineralogical compositions and mechanical properties between the lamina and the matrix. The results showed that:(1) SCBRI leads to the decrease in carbonate mineral content and the significant increase in matrix porosity and laminar cracks. In addition, the damage degree increased at saturation for 6 days.(2) SCBRI weakens the mechanical properties of shale. The scratch depth of laminar and matrix increased by 34.38% and 1.02%, and the fracture toughness decreased by 34.38% and 13.11%. It showed a trend of first increasing and then decreasing.(3) SCBRI enhances the plastic deformation behavior of shale, and the plastic index of lamina and matrix increases by 18.75% and 21.58%, respectively. These results are of great significance for evaluating the mechanical properties of shale oil and gas extraction by CO_(2).展开更多
The influence of supercooled melt forced lamina flow on microsegregation was investigated. The concentration distribution at solid-liquid boundary of binary alloy Ni-Cu was simulated using phase field model coupled wi...The influence of supercooled melt forced lamina flow on microsegregation was investigated. The concentration distribution at solid-liquid boundary of binary alloy Ni-Cu was simulated using phase field model coupled with flow field. The microsegregation, concentration maximum value, boundary thickness of concentration near upstream dendrite and normal to flow dendrite, and downstream dendrite were studied quantitatively in the case of forced lamia flow. The simulation results show that solute field and flow field interact complexly. Compared with melt without flow, in front of upstream dendrite tip, the concentration boundary thickness is the lowest and the concentration maximum value is the smallest for melt with flow. However, in front of downstream dendrite tip, the results are just the opposite. The zone of poor Cu in upstream dendrite where is the most severely microsegregation and shrinkage cavity is wider and the concentration is lower for melt with flow than that without flow.展开更多
Organic rich laminated shale is one type of favorable reservoirs for exploration and development of continental shale oil in China.However,with limited geological data,it is difficult to predict the spatial distributi...Organic rich laminated shale is one type of favorable reservoirs for exploration and development of continental shale oil in China.However,with limited geological data,it is difficult to predict the spatial distribution of laminated shale with great vertical heterogeneity.To solve this problem,taking Chang 73 sub-member in Yanchang Formation of Ordos Basin as an example,an idea of predicting lamina combinations by combining'conventional log data-mineral composition prediction-lamina combination type identification'has been worked out based on machine learning under supervision on the premise of adequate knowledge of characteristics of lamina mineral components.First,the main mineral components of the work area were figured out by analyzing core data,and the log data sensitive to changes of the mineral components was extracted;then machine learning was used to construct the mapping relationship between the two;based on the variations in mineral composition,the lamina combination types in typical wells of the research area were identified to verify the method.The results show the approach of'conventional log data-mineral composition prediction-lamina combination type identification'works well in identifying the types of shale lamina combinations.The approach was applied to Chang 73 sub-member in Yanchang Formation of Ordos Basin to find out planar distribution characteristics of the laminae.展开更多
“Sweet sections”in giant shale oil provinces are preferential fields that primarily support China to increase the reserves and production of continental shale oil.Based on the study of the geological conditions of s...“Sweet sections”in giant shale oil provinces are preferential fields that primarily support China to increase the reserves and production of continental shale oil.Based on the study of the geological conditions of shale oil in the continental basins in China,it was found that the shale stratum in major oil generation windows generally has higher degrees of oil and gas accumulation,and mostly contains oil.Hydrocarbon generation and reservoir capacities are the two key parameters for evaluating and optimizing favorable shale oil provinces.The evaluation index(volume of shale stratum multiplied by total organic carbon(TOC)multiplied by total porosity)for the giant continental shale oil provinces is also proposed.It is optimized that the Upper Triassic Chang 7 Member in the southcentral Ordos Basin,Lower Cretaceous Qing 1 Member in the Gulong-Changling Sag in the Songliao Basin,Middle-Lower Permian in the Junggar Basin,Da’anzhai Member of the Ziliujing Formation of Lower Jurassic in the central and northern Sichuan Basin,and Paleogene oil-rich sag in the Bohai Bay Basin are the five giant continental shale oil provinces.The word“geological sweet sections”in continental shale oil provinces of China refers to favorable shale intervals which are relatively rich in oil,with superior physical properties,and more easily modified and developed commercially under applicable economic and technological conditions.After evaluation,there are mainly two types of“geological sweet sections”of giant continental shale oil developed onshore in China.One type of“geological sweet sections”is generally mudstone with optimal physical properties or a thin tight reservoir,to which the shale oil migrates a short distance.They are medium-to-high-mature zones with a thin sandy shale stratum in the Chang 7 Member in the Ordos Basin,mixed shale stratum in the mediummature Lucaogou Formation in the Jimsar Sag,and multi-layered mixed Paleogene shale stratum in the Bohai Bay Basin.The other type of“geological sweet sections”is generally shale oil residing in various shale reservoir spaces.This type was developed in the Qing 1 Member in the Gulong Sag and Da’anzhai Member in the north-central Sichuan Basin.Free shale oil mainly occurs in shale,sandycarbonate lamina,micro-lamella structure,and micro-fractures.Layers with lamina,lamination,and micro-fractures are generally shale oil“geological sweet sections.”Starting from field tests and the construction of the“geological sweet sections”in giant continental shale oil provinces,the shale oil industry has been rapidly developing and will become an important supplement to domestic oil production in China.展开更多
文摘Shale oil reservoirs are generally characterized by complex mineral compositions, rapid lithofacies changes, and thin laminae. Explorations have confirmed that the type and density of shale laminae significantly influence reservoir quality, highlighting the importance of accurately identifying these laminae through well logging for effective shale reservoir evaluation. Presently, relevant technologies primarily focus on the qualitative identification of shale laminae using vertical slab images from image logs. However, influenced by the complex borehole conditions and image logging quality, this approach is less effective in identifying millimeter-scale laminae. This study proposes a new method for achieving high-resolution slab images and quantitatively evaluating the laminae using electrical image logs. The new method effectively improves the processing accuracy of slab images by delicately flattening and aligning the button electrode curves derived from electrical image logs point by point. Meanwhile, it allows for the accurate quantitative evaluation of the lamina number through precise identification of peaks and troughs in microelectrode curves. As demonstrated by the applications in shale oil reservoirs in the Gulong area in Daqing and the Ganchagou area in Qinghai, the proposed method can significantly improve accuracy compared to traditional slab images. Furthermore, the lamination index calculated using this method is highly consistent with the lamina number observed in cores. This study provides a new technical method for the quantitative lamina evaluation and rock structure analysis of shale reservoirs.
基金National Natural Science Foundation of China(Grant No.42002133,42072150)Science Foundation of China University of Petroleum,Beijing(No.2462021YXZZ003)the Strategic Cooperation Technology Projects of CNPC and CUPB(ZLZX2020-01-06)for the financial supports and permissions to publish this paper
文摘Fine-grained sedimentary rocks have become a research focus as important reservoirs and source rocks for tight and shale oil and gas.Laminae development determines the accumulation and production of tight and shale oil and gas in fine-grained rocks.However,due to the resolution limit of conventional logs,it is challenging to recognize the features of centimeter-scale laminae.To close this gap,complementary studies,including core observation,thin section,X-ray diffraction(XRD),conventional log analysis,and slabs of image logs,were conducted to unravel the centimeter-scale laminae.The laminae recognition models were built using well logs.The fine-grained rocks can be divided into laminated rocks(lamina thickness of<0.01 m),layered rocks(0.01-0.1 m),and massive rocks(no layer or layer spacing of>0.1 m)according to the laminae scale from core observations.According to the mineral superposition assemblages from thin-section observations,the laminated rocks can be further divided into binary,ternary,and multiple structures.The typical mineral components,slabs,and T2spectrum distributions of various lamina types are unraveled.The core can identify the centimeter-millimeter-scale laminae,and the thin section can identify the millimeter-micrometer-scale laminae.Furthermore,they can detect mineral types and their superposition sequence.Conventional logs can identify the meter-scale layers,whereas image logs and related slabs can identify the laminae variations at millimeter-centimeter scales.Therefore,the slab of image logs combined with thin sections can identify laminae assemblage characteristics,including the thickness and vertical assemblage.The identification and classification of lamina structure of various scales on a single well can be predicted using conventional logs,image logs,and slabs combined with thin sections.The layered rocks have better reservoir quality and oil-bearing potential than the massive and laminated rocks.The laminated rocks’binary lamina is better than the ternary and multiple layers due to the high content of felsic minerals.The abovementioned results build the prediction model for multiscale laminae structure using well logs,helping sweet spots prediction in the Permian Lucaogou Formation in the Jimusar Sag and fine-grained sedimentary rocks worldwide.
基金Supported by the National Natural Fund Petrochemical Joint Fund Key Project(U1762217)Fundamental Scientific Research Operations Project of China Central Universities(19CX02009A)
文摘The Chang 73 sub-member of Triassic Yanchang Formation in the Ordos Basin was taken as an example and the lamina types and combinations,reservoir space features and shale oil enrichment patterns in organic-rich shale strata were investigated using core observation,thin section analysis,XRF element measurement,XRD analysis,SEM,high solution laser Raman spectroscopy analysis,and micro-FTIR spectroscopy analysis,etc.According to the mineral composition and thickness of the laminae,the Chang 73 organic-rich shales have four major types of laminae,tuff-rich lamina,organic-rich lamina,silt-grade feldspar-quartz lamina and clay lamina.They have two kinds of shale oil-bearing layers,"organic-rich lamina+silt-grade feldspar-quartz lamina"and"organic-rich lamina+tuff-rich lamina"layers.In the"organic-rich+silt-grade feldspar-quartz"laminae combination shale strata,oil was characterized by relative high maturation,and always filled in K-feldspar dissolution pores in the silt-grade feldspar-quartz laminae,forming oil generation,migration and accumulation process between laminae inside the organic shales.In the"organic-rich+tuff-rich lamina"binary laminae combination shale strata,however,the reservoir properties were poor in organic-rich shales,the oil maturation was relatively lower,and mainly accumulated in the intergranular pores of interbedded thin-layered sandstones.The oil generation,migration and accumulation mainly occurred between organic-rich shales and interbedded thin-layered sandstones.
文摘Novel fully biodegradable thermoplastic composite laminates reinforced with ultrathin wood laminae were prepared through a hot-pressing process by using two different thermoplastic starch(TPS)matrices.The microstructure and physical properties of the resulting unidirectional and bidirectional laminates were studied.The investigated materials presented a complex microstructure,in which the porosity of the wood laminae was almost entirely occluded by the polymer matrix.The mechanical behavior of the laminates was strongly affected by the obtained microstructure,and matrix penetration in wood pores led to biodegradable composites with elastic modulus and tensile strength higher than those of their constituents.Finally,thermal welding and thermoformability tests proved how these materials possess features typical of thermoplastic materials.
基金Supported by China National Science and Technology Major Project(2017ZX05035-001)National Natural Science Fund Project(41572079)
文摘Based on thin-section,argon-ion polished large-area imaging and nano-CT scanning data,the reservoir characteristics and genetic mechanisms of the Lower Silurian Longmaxi shale layers with different laminae and laminae combinations in the Sichuan Basin were examined.It is found that the shale has two kinds of laminae,clayey lamina and silty lamina,which are different in single lamina thickness,composition,pore type and structure,plane porosity and pore size distribution.The clayey laminae are about 100μm thick each,over 15%in organic matter content,over 70%in quartz content,and higher in organic pore ratio and plane porosity.They have abundant bedding fractures and organic matter and organic pores connecting with each other to form a network.In contrast,the silty laminae are about 50μm thick each,5%to 15%in organic matter content,over 50%in carbonate content,higher in inorganic pore ratio,undeveloped in bedding fracture,and have organic matter and organic pores disconnected from each other.The formation of mud lamina and silt lamina may be related to the flourish of silicon-rich organisms.The mud lamina is formed during the intermittent period,and silt lamina is formed during the bloom period of silicon-rich organisms.The mud laminae and silt laminae can combine into three types of assemblages:strip-shaped silt,gradating sand-mud and sand-mud thin interlayers.The strip-shaped silt assemblage has the highest porosity and horizontal/vertical permeability ratio,followed by the gradating sand-mud assemblage and sand-mud thin interlayer assemblage.The difference in the content ratio of the mud laminae to silt laminae results in the difference in the horizontal/vertical permeability ratio.
基金Supported by the National Natural Science Foundation of China(4160211941572079)
文摘Based on various test data, the composition, texture, structure and lamina types of gas-bearing shale were determined based on Well Wuxi 2 of the Silurian Longmaxi Formation in the Sichuan Basin. Four types of lamina, namely organic-rich lamina, organic-bearing lamina, clay lamina and silty lamina, are developed in the Longmaxi Formation of Well Wuxi 2, and they form 2 kinds of lamina set and 5 kinds of beds. Because of increasing supply of terrigenous clasts and enhancing hydrodynamics and associated oxygen levels, the contents of TOC and brittle mineral reduce and content of clay mineral increases gradually as the depth becomes shallow. Organic-rich lamina, organic-rich + organic-bearing lamina set and organic-rich bed dominate the small layers 1-3 of Member 1 of the Longmaxi Formation, suggesting anoxic and weak hydraulic depositional setting. Organic-rich lamina, along with organic-bearing lamina and silty lamina, appear in small layer 4, suggesting increased oxygenated and hydraulic level. Small layers 1-3 are the best interval and drilling target of shale gas exploration and development.
文摘In this study,an in-depth analysis of the types,characteristics,and formation mechanisms of microlaminae and microscopic laminae was conducted in order to precisely examine the link or intersection of stratigraphy and petrology.This study was essentially a sedimentary examination of the minuteness-macro and micro-tiny layers between laminae and pore structure,as well as the types of structures and sedimentation.The results of this study bear important basic subject attributes and significance,as well as practical value for the basic theories and exploration applications of unconventional oil and gas geology.The quantitative data were obtained using the following:field macroscopic observations;measurements;intensive sampling processes;XRD mineral content analysis;scanning electron microscopy;high-power polarizing microscope observations;and micro-scale measurements.The quantitative parameters,such as laminae thicknesses,laminae properties,organic matter laminae,and laminae spatial distributions were unified within a framework,and the correlations among them were established for the purpose of forming a fine-grained deposition micro-laminae evaluation system.The results obtained in this research investigation established a basis for the classification of micro-laminae,and divided the micro-laminae into four categories and 20 sub-categories according to the development thicknesses,material compositions,organic matter content levels,and the spatial distributions of the micro-laminae.The classification scheme of the micro-laminae was divided into two categories and 12 sub-categories.Then,in accordance with the comprehensive characteristics of spatial morphology,the micro-laminae was further divided into the following categories:continuous horizontal laminae;near horizontal laminae;slow wavy laminae;wavy laminae;discontinuous laminae;and lenticular laminae.According to the structural properties of the laminae development,the micro-laminae was divided into the following categories:single laminae structures;laminated laminae structures;interlaminar structures;multiple mixed laminae structures;cyclic laminae structures;and progressive laminae structures.The research results were considered to be applicable for the scientific evaluations of reservoir spaces related to unconventional oil and gas resources.
基金supported by supportedby the China Postdoctoral Science Foundation under Grant Nos.2024M753612 and GZC20233101Supported by the Strategic Cooperation Technology Projects of CNPC and CUPB(ZLZX2020-05)the Science Foundation of China University of Petroleum,Beijing(No.2462023XKBH012).
文摘China's lacustrine shale oil reserves are abundant,making it a key area for future exploration and development.Most lacustrine shales feature a mix of mineral compositions and interlayer sedimentary structures.High-quality reservoirs exhibit significant heterogeneity,which influences the stress distribution during fracturing,leading to complex fracture network patterns.This complexity presents challenges for the comprehensive well logging evaluation of the geological-engineering"double sweet spots"in shale oil,severely restricting efficient development.This study focuses on the impact of shale sedimentary layering on the radial slowness of dipole shear waves.It employs rock physics experiments combined with advanced well logging techniques to explore the relationship between reservoir anisotropy caused by sedimentary layering and reservoir quality,thereby establishing a logging evaluation method for vertical identification of"sweet spots"in lacustrine shale oil.The shales in the Fengcheng Formation of the Mahu Sag into three types according to sedimentary structure scale:laminated,interlayer,and massive.Each type has different mineral compositions,affecting reservoir quality and fracturing potential.Laminated shales develop more fractures under stress along the beddings,showing moderate anisotropy,with reservoir capacity dependent on intercrystalline porosity within carbonate layers.Interlayer shales easily form complex fracture networks,exhibiting significant anisotropy,and their reservoir capacity depends on the porosity within sandy bands.Massive mudstones have the fewest fractures under stress,appearing isotropic with reservoir capacity dependent on matrix pore size.The intensity of reservoir anisotropy correlates positively with storage capacity and the propensity to form irregular and complex fracture networks during hydraulic fracturing.In sections without natural fractures,a larger difference between fast and slow shear waves corresponds to a radial profile shift towards warm tones,indicating stronger anisotropy and better reservoir quality,thus forming complex fracture networks during fracturing.Conversely,a smaller difference leads to a profile energy shift towards cooler tones,indicating stronger isotropy and poorer reservoir quality,hindering the formation of complex fracture networks during hydraulic fracturing.In sections with natural fractures,the difference between fast and slow shear waves exhibits erratic behavior,showing a cross-pattern in radial profiles,indicating strong anisotropy.The presence of natural fractures can synergize with induced fracture networks to form more complex systems,significantly enhancing reservoir productivity.
基金financially supported by the National Natural Science Foundation of China(32100450 and 32471370 to Q.P.,12372302 to J.Q.)the Guangdong Pearl River Talent Program(2021QN02Y781 to Q.P.)the Evident&Shenzhen Bay Laboratory Joint Optical Microscopic Imaging Technology Development Program(S234602004-1 to Q.P.).
文摘Gene expression is regulated by chromatin architecture and epigenetic remodeling in cell homeostasis and pathologies.Histone modifications act as the key factors to modulate the chromatin accessibility.Different histone modifications are strongly associated with the localization of chromatin.Heterochromatin primarily localizes at the nuclear periphery,where it interacts with lamina proteins to suppress gene expression.In this review,we summarize the potential bridges that have regulatory functions of histone modifications in chromatin organization and transcriptional regulation at the nuclear periphery.We use lamina-associated domains(LADs)as examples to elucidate the biological roles of the interactions between histone modifications and nuclear lamina in cell differentiation and development.In the end,we highlight the technologies that are currently used to identify and visualize histone modifications and LADs,which could provide spatiotemporal information for understanding their regulatory functions in gene expression and discovering new targets for diseases.
文摘AIM:To propose a novel glaucoma surgery for rebalancing translaminar pressure difference.METHODS:Three non-human primates with normal eyes and two with laser-induced glaucoma underwent the novel surgical procedure.Cannulation of the subarachnoid space was performed after completion of routine vitrectomy steps.An XEN 45 implant was inserted into the created puncture to communicate between the vitreous body and subarachnoid space.Intraocular pressure(IOP),fundus photography,and spectral-domain optical coherence tomography were assessed at baseline and regular intervals during follow-up.RESULTS:All operated eyes showed IOP reduction in the first postoperative month.Two(2/3)normal eyes and one(1/2)glaucomatous eye maintained lower IOP until 18mo after operation.The XEN 45 implant remained positioned through the lamina cribrosa in all normal eyes but was not detected in two glaucomatous eyes.Complications observed in this study included retinal vascular bleeding in 1/3 normal eyes and XEN implant dislocation in all 2 glaucomatous eyes.CONCLUSION:Subarachnoid space cannulation and mini-shunt implantation may contribute to IOP reduction,possibly by rebalancing translaminar pressure difference and enhancing aqueous humor drainage.The development of a suitable mini-shunt requires further investigation.
基金Supported by the National Natural Science Foundation of China(42302184)Innovation Group Project of Basic Research in Gansu Province,China(22JR5RA045)。
文摘The lamina(combination)types,reservoir characteristics and shale oil occurrence states of organic-rich shale in the Triassic Yanchang Formation Chang 73 sub-member in the Ordos Basin were systematically investigated to reveal the main controlling factors of shale oil occurrence under different lamina combinations.The differential enrichment mechanisms and patterns of shale oil were discussed using the shale oil micro-migration characterization and evaluation methods from the perspectives of relay hydrocarbon supply,stepwise migration,and multi-stage differentiation.The results are obtained in five aspects.First,Chang 73 shale mainly develops five types of lamina combination,i.e.non-laminated shale,sandy laminated shale,tuffaceous laminated shale,mixed laminated shale,and organic-rich laminated shale.Second,shales with different lamina combinations are obviously different in the reservoir space.Specifically,shales with sandy laminae and tuffaceous laminae have a large number of intergranular pores,dissolution pores and hydrocarbon generation-induced fractures.The multi-scale pore and fracture system constitutes the main place for liquid hydrocarbon occurrence.Third,the occurrence and distribution of shale oil in shale with different lamina combinations are jointly controlled by organic matter abundance,reservoir property,thermal evolution degree,mineral composition and laminae scale.The micro-nano-scale pore-fracture networks within shales containing rigid laminae,particularly sandy and tuffaceous laminations,primarily contain free-state light hydrocarbon components.In contrast,adsorption-phase heavy hydrocarbon components predominantly occupy surfaces of organic matter assemblages,clay mineral matrices,and framework mineral particulates.Fourth,there is obvious shale oil micro-migration between shales with different lamina combinations in Chang 73.Generally,such micro-migration is stepwise in a sequence of organic-rich laminated shale→tuffaceous laminated shale→mixed laminated shale→sandy lamiated shale→non-laminated shale.Fifth,the relay hydrocarbon supply of organic matter under the control of the spatial superposition of shales with various laminae,the stepwise migration via multi-scale pore and fracture network,and the multi-differentiation in shales with different lamina combinations under the control of organic-inorganic interactions fundamentally decide the differences of shale oil components between shales with different lamina combinations.
基金supported by the National Natural Science Foundation of China grant(81974150).
文摘Abnormal accumulation of collagen fibrils is a hallmark feature of oral submucous fibrosis(OSF).However,the precise characteristics and underlying mechanisms remain unclear,impeding the advancement of potential therapeutic approaches.Here,we observed that collagen Ⅰ,the main component of the extracellular matrix,first accumulated in the lamina propria and subsequently in the submucosa of OSF specimens as the disease progressed.Using RNA-seq and Immunofluorescence in OSF specimens,we screened the cartilage oligomeric matrix protein(COMP)responsible for the abnormal collagen accumulation.Genetic COMP deficiency reduced arecoline-stimulated collagen I deposition significantly in vivo.In comparison,both COMP and collagen Ⅰ were upregulated under arecoline stimulation in wild-type mice.Human oral buccal mucosal fibroblasts(hBMFs)also exhibited increased secretion of COMP and collagen I after stimulation in vitro.COMP knockdown in hBMFs downregulates arecoline-stimulated collagen Ⅰ secretion.We further demonstrated that hBMFs present heterogeneous responses to arecoline stimulation,of which COMP-positive fibroblasts secrete more collagen Ⅰ.Since COMP is a molecular bridge with Fibril-associated collagens with Interrupted Triple helices(FACIT)in the collagen network,we further screened and identified collagen XIV,a FACIT member,co-localizing with both COMP and collagen Ⅰ.Collagen XIV expression increased under arecoline stimulation in wild-type mice,whereas it was hardly expressed in the Comp^(-/-) mice,even with under stimulation.In summary,we found that COMP may mediates abnormal collagen Ⅰ deposition by functions with collagen XIV during the progression of OSF,suggesting its potential to be targeted in treating OSF.
文摘The annual laminae gray level variations in the stalagmite TS9501 of Shihua Cave, Beijing are studied in detail. The environmental factors influencing the laminae gray level are also analyzed. The following conditions may be necessary to the study on the lamina gray level. A) The seasonal differences of climate in the studied area are strong. B) The cave has a rapid and simple hydrological connection with the surface, such that the gray level variation is great; therefore, climatic changes can be more clearly recorded in a stalagmite. C) No water from other sources due to lateral flow adds to the seepage over the cave. D) There are more organic impurities than inorganic ones, whose content changes distinctly with time in the sample. By comparison with the modern instrumental climate records, it was found that the gray level of laminae is mainly related to the air temperature, especially the summer mean temperature. Therefore, the gray level can be used as a proxy of the air temperature. The variation of the lamina gray level also represents the oscillation of Indian summer monsoon as identified in the modern climate records. The variability of the temperature in Beijing area over the last 1 ka is reconstructed. The results show that there are several cold periods corresponding to historical records. An important phenomenon is noticed that the climatic pattern before about 1400AD is different from that after about 1400AD. In Beijing area, before about 1400AD, low amplitude and high frequency temperature oscillations dominated the signal. The climate pattern is warm-dry and cold-wet. After about 1400AD, both the temperature and rainfall varied synchronously, temperature oscillated strongly and the Little Ice Age occurred. The climate pattern is cold-dry and warm-wet. This transition of the climate pattern is also observed in other worldwide paleoclimatic records, demonstrating that there was a global climate event at about 1400AD.
基金supported by the National Natural Science Foundation of China (52374014)the Fundamental Research Funds for the Central Universities (2024ZKPYSB03)。
文摘The mechanism of SC-CO_(2)-brine-rock interaction(SCBRI) and its effect on the mechanical properties of shale are crucial for shale oil development and CO_(2)sequestration. To clarify the influence of SCBRI on the micromechanics of shale, the lamina and matrix of shale were saturated with SC-CO_(2)-brine for 2, 4, 6,and 8 days, respectively. The micro-scratch technique was then used to measure the localized fracture toughness before and after SC-CO_(2)-brine saturation. Combining the micro-scratch results with SEM-QEMSCAN-EDS analysis, the differences in mineral composition and mechanical properties of lamina(primarily composed of carbonate minerals) and matrix(primarily composed of clay minerals) were studied. The QEMSCAN analysis and micro-scratch results indicate distinct mineralogical compositions and mechanical properties between the lamina and the matrix. The results showed that:(1) SCBRI leads to the decrease in carbonate mineral content and the significant increase in matrix porosity and laminar cracks. In addition, the damage degree increased at saturation for 6 days.(2) SCBRI weakens the mechanical properties of shale. The scratch depth of laminar and matrix increased by 34.38% and 1.02%, and the fracture toughness decreased by 34.38% and 13.11%. It showed a trend of first increasing and then decreasing.(3) SCBRI enhances the plastic deformation behavior of shale, and the plastic index of lamina and matrix increases by 18.75% and 21.58%, respectively. These results are of great significance for evaluating the mechanical properties of shale oil and gas extraction by CO_(2).
基金Project (10964004) supported by the National Natural Science Foundation of ChinaProject (20070731001) supported by Research Fund for the Doctoral Program of ChinaProject (096RJZA104) supported by the Natural Science Foundation of Gansu Province,China
文摘The influence of supercooled melt forced lamina flow on microsegregation was investigated. The concentration distribution at solid-liquid boundary of binary alloy Ni-Cu was simulated using phase field model coupled with flow field. The microsegregation, concentration maximum value, boundary thickness of concentration near upstream dendrite and normal to flow dendrite, and downstream dendrite were studied quantitatively in the case of forced lamia flow. The simulation results show that solute field and flow field interact complexly. Compared with melt without flow, in front of upstream dendrite tip, the concentration boundary thickness is the lowest and the concentration maximum value is the smallest for melt with flow. However, in front of downstream dendrite tip, the results are just the opposite. The zone of poor Cu in upstream dendrite where is the most severely microsegregation and shrinkage cavity is wider and the concentration is lower for melt with flow than that without flow.
基金co-supported by the National Natural Science Foundation of China(Grant Nos.U1762217,42072161)。
文摘Organic rich laminated shale is one type of favorable reservoirs for exploration and development of continental shale oil in China.However,with limited geological data,it is difficult to predict the spatial distribution of laminated shale with great vertical heterogeneity.To solve this problem,taking Chang 73 sub-member in Yanchang Formation of Ordos Basin as an example,an idea of predicting lamina combinations by combining'conventional log data-mineral composition prediction-lamina combination type identification'has been worked out based on machine learning under supervision on the premise of adequate knowledge of characteristics of lamina mineral components.First,the main mineral components of the work area were figured out by analyzing core data,and the log data sensitive to changes of the mineral components was extracted;then machine learning was used to construct the mapping relationship between the two;based on the variations in mineral composition,the lamina combination types in typical wells of the research area were identified to verify the method.The results show the approach of'conventional log data-mineral composition prediction-lamina combination type identification'works well in identifying the types of shale lamina combinations.The approach was applied to Chang 73 sub-member in Yanchang Formation of Ordos Basin to find out planar distribution characteristics of the laminae.
基金supported by the National High-Level Special Talent Support Plan(the fourth batch)the PetroChina’s“14th Five Year Plan”Forward-Looking Basic Science and Technology Project(No.2021DJ18)。
文摘“Sweet sections”in giant shale oil provinces are preferential fields that primarily support China to increase the reserves and production of continental shale oil.Based on the study of the geological conditions of shale oil in the continental basins in China,it was found that the shale stratum in major oil generation windows generally has higher degrees of oil and gas accumulation,and mostly contains oil.Hydrocarbon generation and reservoir capacities are the two key parameters for evaluating and optimizing favorable shale oil provinces.The evaluation index(volume of shale stratum multiplied by total organic carbon(TOC)multiplied by total porosity)for the giant continental shale oil provinces is also proposed.It is optimized that the Upper Triassic Chang 7 Member in the southcentral Ordos Basin,Lower Cretaceous Qing 1 Member in the Gulong-Changling Sag in the Songliao Basin,Middle-Lower Permian in the Junggar Basin,Da’anzhai Member of the Ziliujing Formation of Lower Jurassic in the central and northern Sichuan Basin,and Paleogene oil-rich sag in the Bohai Bay Basin are the five giant continental shale oil provinces.The word“geological sweet sections”in continental shale oil provinces of China refers to favorable shale intervals which are relatively rich in oil,with superior physical properties,and more easily modified and developed commercially under applicable economic and technological conditions.After evaluation,there are mainly two types of“geological sweet sections”of giant continental shale oil developed onshore in China.One type of“geological sweet sections”is generally mudstone with optimal physical properties or a thin tight reservoir,to which the shale oil migrates a short distance.They are medium-to-high-mature zones with a thin sandy shale stratum in the Chang 7 Member in the Ordos Basin,mixed shale stratum in the mediummature Lucaogou Formation in the Jimsar Sag,and multi-layered mixed Paleogene shale stratum in the Bohai Bay Basin.The other type of“geological sweet sections”is generally shale oil residing in various shale reservoir spaces.This type was developed in the Qing 1 Member in the Gulong Sag and Da’anzhai Member in the north-central Sichuan Basin.Free shale oil mainly occurs in shale,sandycarbonate lamina,micro-lamella structure,and micro-fractures.Layers with lamina,lamination,and micro-fractures are generally shale oil“geological sweet sections.”Starting from field tests and the construction of the“geological sweet sections”in giant continental shale oil provinces,the shale oil industry has been rapidly developing and will become an important supplement to domestic oil production in China.
