Abstracts

SequenceformationsandsandbodydevelopmentcharacteristicsofKalashayiFormationofCarboniferousintheSangtamuAreaofTahe/2022,46(4):1-11

XIE Caizhu,FU Heng,ZHU Mengqi,WANG Wenbo

(CollegeofEnergy,ChengduUniversityofTechnology,Chengdu,Sichuan610059,China)

Abstract:Combined with logging wells and seismic data,we studied the sequence strata of the Lower Carboniferous Kalashayi Formation in the Sangtamu Area of Tahe,discussed the relationship between sand development characteristics and sequence formations,analyzed the effects of tectonic settlement,sea level changes and material source supply on the development characteristics of sequence formations and sand bodies.The results show that the Kalashayi Formation in the study area can be further divided into 6 tertiary sequences (SQ6-SQ1) in a secondary sequence.The upper mudstone section is divided into a tertiary sequence (SQ6),and the sandstone section is divided into 5 tertiary sequences (SQ5-SQ1).Each tertiary sequence only developed the transgressive system domain and the high-level system domain.The Kalashayi Formation mainly developed braided river delta and shelf sedimentary facies.Two kinds of microphase sandbodies,the underwater shunt channel and shuntchannel,are mainly developed in the inflection delta plain and leading edge in the high-level system domain of SQ5-SQ1.The sand body of the shunt river shows strips of sand in the longitudinal superposition and horizontal splicing with each other,and some are superimposed or isolated,not far from the lateral extension.Longitudinally,the distribution of sand in the underwater diversion channel is wider,and the horizontal parting river extends wider,the overall thickness of the sand body is thicker and the continuity is good,and the sand thickness in the direction of the source shows a significant thinning trend.Tectonic subsidence and global relative sea level change control the development and internal structural characteristics of the third order sequence in the study area,and further control the development of sand bodies.Provenance controls the filling of sediment and thus controls the vertical characteristics and evolution of sand bodies.This result provides guidance for Carboniferous research and exploration in the Tahe Area.

Keywords:sequence framework;system domain;the sedimentary facies;characteristics of sand body development;Kalashayi Formation;Carboniferous;Sangtamu Area

Heterogeneityofshalegasreservoirsinmarine-continentaltransitionalfaciesanditscontrollingfactors:anexampleofShanxiFormationinDaning-JixianBlockoneasternmarginofOrdosBasin/2022,46(4):12-23

WU Jin1,2,XIAO Yufeng1,2,LIU Dan1,2,LIU Xin3,GUO Wei1,2,LI Shuxin4,GAO Jinliang1,2,LIN Wen1,2

(1.PetroChinaResearchInstituteofPetroleumExploration&Development,Beijing100083,China;2.NationalEnergyShaleGasR&D(Experimental)Center,Beijing100083,China;3.ChangqingOilfieldCompanyofChinaNationalPetroleumCorporation,Xi'an,Shaanxi710000,China;4.PetroChinaCoalbedMethaneCompanyLimited,Beijing100028,China)

Abstract:Shale gas reservoirs are strongly heterogeneous because the deposition of marine-continental transitional shale is under the dual control of marine and terrestrial environments.Systematic analyses were performed to investigate shale reservoir heterogeneity in the Shan23submember(P1s23)of the Shanxi Formation in the Daning-Jixian Block on the eastern margin of the Ordos Basin,including core observation,mineral analysis of bulk rock through X-ray diffraction,organic maceral analysis of kerogen,total organic carbon(TOC) content measurement,field emission scanning electron microscopy,low-temperature gas adsorption,and high-pressure mercury injection.The results showed that macroscopic shale reservoir heterogeneity in the Shanxi Formation included mineral composition,organic matter content and kerogen types,whereas microscopic heterogeneity included reservoir space type and pore structure parameters.The upper part of P1s23mainly contained tidal-dominated deltaic shale with a low content of brittle minerals(average value is 39.2%),a low TOC content(average value is 2.3%),type Ⅲ kerogen,poor development of organic pores,and poor pore structure parameters.It is a nonpremium shale gas reservoir.The lower part of P1s23is dominantly estuarine-bay shale in which the shales of the closed lagoon and bay have a high content of brittle minerals(average values are 74.1% and 67.2%,respectively),a high TOC content(average values are 7.3% and 11.2%,respectively),type Ⅱ2kerogen,diverse types of reservoir space,and numerous complex organic matter pores that developed with excellent pore structure parameters.It is a high-quality shale gas reservoir.The shale gas reservoir heterogeneity is controlled by depositional environment and diagenesis.Formation of type Ⅱ2kerogen and numerous organic bubble pores are favorable in the closed lagoon and bay,with biogenic silicate contributing to the formation and maintenance of organic pores.Deltaic shales are characterized by type Ⅲ kerogen and poorly developed organic pores,with limited contribution from terrigenous siliceous materials to the reservoir space.The study of reservoir heterogeneity lays the foundation for the selection of the "sweet spot" section of marine-continental transitional shale gas.

Keywords:marine-continental transitional facies;shale gas reservoir;heterogeneity;controlling factors;Shanxi Formation;Ordos Basin

LI Linjing1,2,HU Mingyi1,LYU Qiqi1,SHU Shuang3,WANG Tongshan4,SONG Daofu5,ZHANG Yan1

(1.SchoolofGeosciences,YangtzeUniversity,Wuhan,Hubei430100,China;2.HubeiGeologicalSurvey,Wuhan,Hubei430034,China;3.No.8OilProductionPlantofChangqingOilfieldBranchCompanyLimited,PetroChina,Xi'an,Shaanxi710000,China;4.ResearchInstituteofPetroleumExploration&Development,PetroChina,Beijing100083,China;5.StateKeyLaboratoryofPetroleumResourcesandProspecting,ChinaUniversityofPetroleum(Beijing),Beijing102249,China)

Abstract:The Huangqikou Formation,the first sedimentary cover over the ancient crystalline basement of Helan Mountains,is subject to controversy over the issue of its age.By using the method of LA-ICP-MS,the U-Pb date of detrital zircons from dark-gray glauconite-bearing fine quartz sandstones in the Huangqikou Formation of Baisikou Section,Yinchuan was carried out.The results showed that the zircon particles were mostly ellipsoidal,followed by short prismatic,subrounded and subangular in shape,with particle sizes ranging from 40 to 130 μm.Zircons are mostly magmatic origin with concussive annulus structures.The Th/U ratio of zircon ranges from 0.12 to 1.81,most of which are larger than 0.40,most of thezircons are magmatic origin with oscillatory zoning structure,and part of them may be affected by metamorphic events;the age of207Pb/206Pb data ranges from 1 680 to 2 606 Ma,with the apparent main peak of 1 890 Ma and several other secondary peak(2 345,2 514 and 2 576 Ma) in the age spectrum.The age of the youngest detrital zircon was(1 680±40)Ma.The analysis of the age peaks and composition of detrital zircon shows that:the zircon age of 2 700-2 450,2 040-1 950,1 950-1 800,1 800-1 680 Ma correspond to the Neo-Carcinogenic event of the North China Craton,the formation of the Neogene continental arc granitoids in the study area,the formation of the Western North China Block due to the collision between the Yinshan Block and the Ordos Block,and the Middle Proterozoic basement ascendant and intracontinental rift events of the North China Craton.The Huangqikou Formation belongs to Middle Proterozoic Changcheng System;the khondalite series in the northern margin of the North China Craton is the main provenance,and the continental crust material and the Taihang-Lyuliang basic dyke in Late Neoarchean(about 2 500 Ma) are the secondary source areas.Providing new chronology data for further establish the contact relationship of Changcheng System and underlying Palaeoproterozoic

Keywords:detrital zircon;U-Pb dating;North China Craton;Huangqikou Formation;Changcheng System;Baisikou Section;Helan Mountains

EvolutionarycharacteristicsoffaultsystemanditscontroleffectonhydrocarbonaccumulationinWushiSag,BeibuwanBasin/2022,46(4):37-47

MAN Yong1,FAN Caiwei2,XUE Hongtao1,JIN Qiuyue1,HUANG Qing1

(1.HainanBranchofCNOOC,Haikou,Hainan570312,China;2.ZhanjiangBranchofCNOOC,Zhanjiang,Guangdong524057,China)

Abstract:In order to clarify the evolution characteristics of the fault system in Wushi Sag,Beibuwan Basin,the author basing on 3D seismic date in Wushi Sag,combining with the changes of the regional stress field,analyzed the characteristics and evolution law of fault system,established the rotation of the extension-detachment fault development model controlled by the oblique extensional block in Wushi Sag,and studied its control effect on hydrocarbon accumulation.The study shows that:from the Paleocene to the Early Eocene,the extensional stress field is nearly perpendicular to the existing north-east trending faults.During this period,the faults are mainly characterized by extensional evolution;from the Mid-Late Eocene to the Oligocene,the extensional stress field rotates clockwise and intersects the pre-existing north-east fault at an acute angle,which mankes the early fault was activated,and due to the thick plastic oil shale at the top and bottom of the second member of the Liushagang,the faults shows the extension-slip evolution characteristics under the joint control of oblique tension and plastic formation;as the stress continues to rotate,the up fault of the detachment fault develops a tension-torsional adjustment fault,forming a floweriness structural.The developing extensional faults in the sag control the spread of Eocene hydrocarbon source rock and large reservoir collectives;extension-slip faults control the difference of the structural zone and the formation of the trap groups,among them,the throw side of slip zone shows the "anticlinal rise",the gas-oil convergence background is superior,and it is the most favorable enrichment area in the Wushi Sag.This result has guiding significance for gas-oil exploration and zone optimization in Wushi Sag.

Keywords:Beibuwan Basin;Wushi Sag;stress direction rotation;oblique extensional;fault characteristics;hydrocarbon accumulation

Occurrencestateandcharacteristicsoforganicmatterinover-maturemarineshale:acasestudyfortheLowerCambrianNiutitangFormationinGuizhouProvince/2022,46(4):48-61

YU Yin1,XIA Peng1,2,WANG Yingbiao3,NING Shitan1,ZHONG Yi1,MOU Yuliang1,2,LI Kunjie4

(1.CollegeofResourceandEnvironmentalEngineering,GuizhouUniversity,Guiyang,Guizhou550025,China;2.KeyLaboratoryofMinistryofEducationforGeologicalResourcesandEnvironment,GuizhouUniversity,Guiyang,Guizhou550025,China;3.JidongOilfieldCompanyofCNPC,Tangshan,Hebei063200,China;4.HuaxinGasGroupCompanyLimited,Taiyuan,Shanxi030026,China)

Abstract:The black shale deposited in the Lower Cambrian Niutitang Formation in Guizhou is a favorable source of the rock.Taking the shale of the Lower Cambrian Niutitang Formation in Guizhou as the research object,the shale organic matter occurrence state and characteristics were studied by scanning electron microscopy,elemental analysis,gas adsorption and other experimental methods.The results show that the organic matter in the over-mature marine shale of the Niutitang Formation mainly occurs in four states:banding,agglomerated,filling,and mutual wrapping.Banded organic matter is controlled by compaction,and pores are generally not developed.The overall pores of the agglomerated organic matter are poorly developed,but the pores of the organic matter distributed in the middle of the rigid mineral particles are well developed.Pores are more developed in filling organic matter and wrapped organic matter,and this part of the organic matter is distributed in the intergranular pores,and the particle skeleton support can effectively protect the organic matter pores.There are obvious differences in the elemental composition of organic matter in different occurrence states.Shale lithofacies affect the abundance and occurrence state of organic matter to a certain extent,the occurrence state of organic matter determines the pore structure of organic matter,the abundance of organic matter affects the proportion of organic matter pores in rock pores.Accurately describe the relationship between shale lithofacies,organic occurrence state and organic pore structure,the results can provide new ideas for the evaluation of shale gas reservoirs in the Niutitang Formation.

Keywords:organic matter;occurrence state;pore structure;marine shale;Niutitang Formation;Lower Cambrian;Guizhou

Fracturepredictionand3DgeologicalmodelingbasedonpartitioncalibrationofFaultLikelihoodattribute:acasestudyofthe2ndmemberofXujiaheFormationinXinchangGasField,WestSichuanDepression,SichuanBasin/2022,46(4):62-76

SHANG Xiaofei,WANG Mingchuan,LI Meng

(ResearchInstituteofPetroleumExplorationandProduction,SINOPEC,Beijing102206,China)

Abstract：The reservoir of the 2nd member of Xujiahe Formation in Xinchang Area of Western Sichuan Depression is relatively tight and more natural fractures are developed.Based on Fault Likelihood(FL) attribute extraction and preliminary treatment,combined with the fracture development revealed by drilling wells,the calibration between well and seismic was carried out through the structural unit partition,and the fracture response threshold interval of each structural unit was determined.Furthermore,the equal-scale normalization method was used to integrate the adjusted attributes of each structural unit.The results show that the coincidence rate of FL attribute with drilling fractures after partition calibration is more than 85%,and the correlation between FL attribute and effective fracture density with dip angle greater than 30° is the best,which greatly improves the accuracy of FL attribute in fracture prediction.Based on FL partition calibration technology,a 3D geological model of fracture is established,which can reflect the spatial distribution of fractures and their parameters more accurately,and provide more accurate quantitative data guarantee for productivity construction of Xinchang tight sandstone gas reservoir.

Keywords：Fault Likelihood attribute;fracture prediction;fracture modeling;2nd member of Xujiahe Formation;Xinchang Gas Field;Western Sichuan Depression

WaterinfluenceonmicroinorganicporestructureofLongmaxioutcropshale/2022,46(4):77-85

GU Keming1,2,NING Zhengfu1,2,WANG Zhipeng1,2

(1.StateKeyLaboratoryofPetroleumResourcesandProspecting,ChinaUniversityofPetroleum(Beijing),Beijing102249,China;2.CollegeofPetroleumEngineering,ChinaUniversityofPetroleum(Beijing),Beijing102249,China)

Abstract:Hydraulic fracturing is essential method for shale gas development,due to strong hydrophilicity of shale,the chemical and physical reaction between water and minerals can directly cause changes of pore structure.By utilizing Longmaxi outcrop,acquire SEM pictures or pore size distribution curves before and after processing degree through equilibrium moisture test,nitrogen adsorption test and SEM observation.Parameter changes of average value,kurtosis,median and characteristic length between mineral particles before and after different processing degree by adopting Image-Pro Plus and SPSS to analyse inorganic pore parameters.The results show that:water invasion speed is initially larger then gets smaller,the relationship between micro pore structure parameter and saturation is nonlinear;two opposite mechanisms of water influence on shale are the compressing force of clay expansion and enlarging function of water flush and substrate clay expansion,new fracture or pore is caused by shrinkage of clay mineral.Water influence on micro pore structure is complicated,moving particles and twisted arrangement of mineral particles can reduce the geological structure stability and rock percolation.

Keywords:Longmaxi Formation;shale;inorganic pore;water saturation;SEM;nitrogen adsorption experiment;waterbased fracturing fluid

Effectofheatingtemperatureonthemicroscopicmechanismofgelatinprocessofwaxycrudeoil/2022,46(4):86-97

GUO Liping1,JI Junmei1,2,ZHANG Jiajun1,ZHANG Lili3,HE Huaidong4,SHI Shaojun5,YANG Bao3

(1.KeyLaboratoryofEnhancedOilandGasRecovery,MinistryofEducation,NortheastPetroleumUniversity,Daqing,Heilongjiang163318,China;2.SINOPECChongqingShaleGasCompanyLimited,Chongqing408400,China;3.OilRecoveryPlantNo.2,DaqingOilfieldCompanyLimited,Daqing,Heilongjiang163414,China;4.OilRecoveryPlantNo.3,DaqingOilfieldCompanyLimited,Daqing,Heilongjiang163113,China;5.ExplorationandDevelopmentResearchInstitute,JilinOilfieldCompanyLimited,Songyuan,Jilin138000,China)

Abstract:Heating temperature is the main factor affecting the gelling degree of waxy crude oil.According to the physical property data of oil products measured in the macro experiment,the wax crystal,colloid and asphaltene molecular models closest to the actual molecular structure of the experimental crude oil are selected to construct the waxy crude oil system.The molecular dynamics simulation is carried out with Materials Studio software to explore the influence of heating temperature on the micro mechanism of the gelation process of waxy crude oil.The results show that the condensation point of waxy crude oil can be determined by the curves of density-temperature and self-diffusion coefficient-temperature.When the temperature decreases,the molecular chain of waxy crude oil system changes from straight chain to curl state,and changes significantly at the condensation point temperature.The aggregation among the same molecules of wax crystal is the main factor of the gelation of waxy crude oil.The radial distribution function(RDF) between wax molecules has a peak value and concentration,which significantly increases the RDF peak value of the heating temperature at which the solidification point deteriorates.The results provide a basis for the study of the rheological properties of waxy crude oil gelling system from the perspective of intermolecular interaction mechanism.

Keywords:waxy crude oil;gelation process;condensation point;heating temperature;microscopic mechanism;radial distribution function

Residuallawanalysisofporescaletransportinporousmediaofshaleoil/2022,46(4):98-104

LI Dong1,ZHENG Shuangjin1,REN Chunmei2,ZHAO Xuefeng3,PU Yu1,4,CHANG Zehui5

(1.SchoolofCivilEngineeringandArchitecture,NortheastPetroleumUniversity,Daqing,Heilongjiang163318,China;2.TheThirdBranchofWatreProductionCompany,PetroleumAdministrationBureau,Daqing,Heilongjiang163000,China;3.DaqingOilfieldEngineeringCompanyLimited,Daqing,Heilongjiang163453,China;4.KeyLaboratoryofEnhancedOilandGasRecovery,MinistryofEducation,NortheastPetroleumUniversity,Daqing,Heilongjiang163318,China;5.SchoolofEnergyandPowerEngineering,InnerMongoliaUniversityofTechnology,Hohhot,InnerMongolia010051,China)

Keywords:shale oil;pore scale;level set method;transport characteristics;multiple transports;residual oil

Experimentonphysicalpropertiesofhotdryrockunderhightemperatureaction/2022,46(4):105-116

QIN Hao1,2,WANG Daobing1,ZHENG Chen1,DONG Yongcun1,ZHANG Wei1,SUN Dongliang1,YU Bo1

(1.SchoolofMechanicalEngineering,BeijingInstituteofPetrochemicalTechnology,Beijing102617,China;2.Ji'nanBranchofChinaPetroleumandChemicalCorporation,Ji'nan,Shandong250101,China)

Abstract:In order to reveal the variation of physical-mechanical properties of hot dry rocks under high temperature,the changes of porosity,permeability and thermal conductivity of hot dry rocks under different temperature conditions were analyzed.Triaxial and uniaxial compression tests are used to reveal the variation rules of fracture toughness,compressive strength and other mechanical properties of hot dry rock under high temperature.The results show that:the porosity of hot dry rack increases by 0.86%,which is nearly 2.4 times of the initial state,the permeability increases by more than 140%,and the thermal conductivity of hot dry rock decreases by more than 49% at 400 ℃,respectively.As the temperature rises,the plasticity of hot dry rock gradually increases and the strength decreases.When the temperature exceeds 300 ℃,the compressive strength decreases rapidly,the elastic modulus drops by more than 10% compared with the normal temperature,and Poisson's ratio basically decreases linearly.The high-temperature thermal stress promotes the development of pore structure in hot dry rocks,leading to the continuous movement of acoustic emission(AE) events towards the early stress loading stage,and the fracture toughness gradually decreases with the temperature rise.The fracture toughness of hot dry rocks at 600 ℃ is only 22.4% compared with the normal temperature.The results can provide a reliable reference for reservoir reconstruction design of artificial heat exchange system of hot dry rocks.

Keywords:hot dry rock;high temperature effect;mechanical properties;thermophysical properties;acoustic emission(AE)