In order to determine the planar and volume distribution of sand bodies of the Jurassic Badaowan formation in Block T13 of Junggar basin,we used analysis of field outcrop and 3D seismic data,which play an essential ro...In order to determine the planar and volume distribution of sand bodies of the Jurassic Badaowan formation in Block T13 of Junggar basin,we used analysis of field outcrop and 3D seismic data,which play an essential role in areas of sparse well coverage.We describe sedimentary facies characteristics,sand body planforms,width and connectivity patterns of sand bodies,and vertical associations and successions by acoustic impedance inversion technology and sedimentological theory.Results of our study show braided fluvial strata deposits in the Jurassic Badaowan formation.Each sand body is approximately lenticular in shape.The width of each sand body falls in the range 100～800 m,with most between 200 and 400 m.The sand bodies vary in thickness from 4 to 13 m,with most below 9 m.The width/thickness ratios lie in the range 20～55.The connectivity of braided fluvial channel sand bodies is controlled by changes of accommodation space.One fining-upward sedimentary cycle of base-level rise is recognized in Badaowan formation,representing an upward rise of base level.The connectivity of sand bodies was found to be greatest in the early stage of base-level rise,becoming progressively worse with increasing base-level rise.展开更多
The Jurassic Badaowan Formation on the southern slope of the Mahu Sag has a shallow burial depth and abundant oil and gas resources.On the basis of clarifying the basic characteristics of the reservoir,an in-depth ana...The Jurassic Badaowan Formation on the southern slope of the Mahu Sag has a shallow burial depth and abundant oil and gas resources.On the basis of clarifying the basic characteristics of the reservoir,an in-depth analysis is conducted on the control of sedimentation and diagenesis on the reservoir genesis.The reservoir is mainly composed of lithic sandstone and feldspathic lithic sandstone;the types of reservoir space are mainly intergranular pores and intragranular pores,belonging to a low-porosity and ultra-low-permeability reservoir.The sedimentary environment is the underwater distributary channel of the delta front subfacies,and the distribution of sedimentary facies determines the distribution of sand bodies.Compaction is the main factor destroying primary pores.The changes in reservoir physical properties are mainly controlled by sedimentation and diagenesis.Sedimentation lays the material foundation for reservoir formation,while diagenesis plays a role in later transformation of the reservoir.The research results can provide ideas and directions for the next exploration and development of the Mahu Sag.展开更多
Identifying the shale gas prospect is crucial for gas extraction from such reservoirs.Junggar Basin(in Northwest China)is widely considered to have high potential as a shale gas resource,and the Jurassic,the most sign...Identifying the shale gas prospect is crucial for gas extraction from such reservoirs.Junggar Basin(in Northwest China)is widely considered to have high potential as a shale gas resource,and the Jurassic,the most significant gas source strata,is considered as prospective for shale gas exploration and development.This study evaluated the Lower Jurassic Badaowan Formation shale gas potential combined with geochemical,geological,and well logging data,and built a three-dimensional(3D)model to exhibit favorable shale gas prospects.In addition,methane sorption capacity was tested for verifying the prospects.The Badaowan shale had an average total organic carbon(TOC)content of 1.30 wt.%and vitrinite reflectance(Ro)ranging from 0.47%to 0.81%with dominated type III organic matter(OM).X-ray diffraction(XRD)analyses showed that mineral composition of Badaowan shale was fairly homogeneous and dominated by clay and brittle minerals.67 wells were used to identify prospective shale intervals and to delineate the area of prospects.Consequently,three Badaowan shale gas prospects in the Junggar Basin were identified:the northwestern margin prospect,eastern Central Depression prospect and Wulungu Depression prospect.The middle interval of the northwestern margin prospect was considered to be the most favorable exploration target benefitted by wide distribution and high lateral continuity.Generally,methane sorption capacity of the Badaowan shale was comparable to that of the typical gas shales with similar TOC content,showing a feasible gas potential.展开更多
基金Financial support for this work,provided by the National Basic Research Program of China(No.2006 CB202300),
文摘In order to determine the planar and volume distribution of sand bodies of the Jurassic Badaowan formation in Block T13 of Junggar basin,we used analysis of field outcrop and 3D seismic data,which play an essential role in areas of sparse well coverage.We describe sedimentary facies characteristics,sand body planforms,width and connectivity patterns of sand bodies,and vertical associations and successions by acoustic impedance inversion technology and sedimentological theory.Results of our study show braided fluvial strata deposits in the Jurassic Badaowan formation.Each sand body is approximately lenticular in shape.The width of each sand body falls in the range 100～800 m,with most between 200 and 400 m.The sand bodies vary in thickness from 4 to 13 m,with most below 9 m.The width/thickness ratios lie in the range 20～55.The connectivity of braided fluvial channel sand bodies is controlled by changes of accommodation space.One fining-upward sedimentary cycle of base-level rise is recognized in Badaowan formation,representing an upward rise of base level.The connectivity of sand bodies was found to be greatest in the early stage of base-level rise,becoming progressively worse with increasing base-level rise.
文摘The Jurassic Badaowan Formation on the southern slope of the Mahu Sag has a shallow burial depth and abundant oil and gas resources.On the basis of clarifying the basic characteristics of the reservoir,an in-depth analysis is conducted on the control of sedimentation and diagenesis on the reservoir genesis.The reservoir is mainly composed of lithic sandstone and feldspathic lithic sandstone;the types of reservoir space are mainly intergranular pores and intragranular pores,belonging to a low-porosity and ultra-low-permeability reservoir.The sedimentary environment is the underwater distributary channel of the delta front subfacies,and the distribution of sedimentary facies determines the distribution of sand bodies.Compaction is the main factor destroying primary pores.The changes in reservoir physical properties are mainly controlled by sedimentation and diagenesis.Sedimentation lays the material foundation for reservoir formation,while diagenesis plays a role in later transformation of the reservoir.The research results can provide ideas and directions for the next exploration and development of the Mahu Sag.
基金This work was supported by the special program(Grant No.2009GYXQ15-09-03)of shale gas potential assessment and selection of favorable exploration areas in China of the Research Center of Oil and Gas Resources of the Ministry of Land and Resources.
文摘Identifying the shale gas prospect is crucial for gas extraction from such reservoirs.Junggar Basin(in Northwest China)is widely considered to have high potential as a shale gas resource,and the Jurassic,the most significant gas source strata,is considered as prospective for shale gas exploration and development.This study evaluated the Lower Jurassic Badaowan Formation shale gas potential combined with geochemical,geological,and well logging data,and built a three-dimensional(3D)model to exhibit favorable shale gas prospects.In addition,methane sorption capacity was tested for verifying the prospects.The Badaowan shale had an average total organic carbon(TOC)content of 1.30 wt.%and vitrinite reflectance(Ro)ranging from 0.47%to 0.81%with dominated type III organic matter(OM).X-ray diffraction(XRD)analyses showed that mineral composition of Badaowan shale was fairly homogeneous and dominated by clay and brittle minerals.67 wells were used to identify prospective shale intervals and to delineate the area of prospects.Consequently,three Badaowan shale gas prospects in the Junggar Basin were identified:the northwestern margin prospect,eastern Central Depression prospect and Wulungu Depression prospect.The middle interval of the northwestern margin prospect was considered to be the most favorable exploration target benefitted by wide distribution and high lateral continuity.Generally,methane sorption capacity of the Badaowan shale was comparable to that of the typical gas shales with similar TOC content,showing a feasible gas potential.
