Located in the middle of the Tarim Basin, Tazhong is a typical area of compound reservoirs rich in oil and gas found in the Carboniferous, Silurian and Ordovician strata. The proved, probable and possible reserves （3...Located in the middle of the Tarim Basin, Tazhong is a typical area of compound reservoirs rich in oil and gas found in the Carboniferous, Silurian and Ordovician strata. The proved, probable and possible reserves （3P reserves） in the area amount to 5×108 tons, so it is of great significance to study the advances and problems in hydrocarbon exploration in the Tazhong area. On the basis of exploration history and analysis of scientific problems, we outline eight achievements： distribution characteristics of reservoirs, stages of reservoir formation, different sources of oil and gas and their respective contributions, the effective regional caprock and reservoir-caprock combinations dominating the vertical distribution of hydrocarbon reservoirs, the control of the Tazhong Palaeo-uplift on reservoir formation and establishing geologic models, structure balance belts influencing the reconstruction and residual potential of reservoirs after accumulation, the rules and mechanisms of fractures controlling oil and gas, and the types of favorable reservoirs and their characteristics of controlling oil and gas distribution. We further point out the main problems about the oil and gas exploration in the Tazhong area and put forward some relevant proposals.展开更多
Previously,troughs in continental faulted depressions were usually considered as a zone of hydrocarbon generation and expulsion rather than a zone for hydrocarbon accumulation.If they were confirmed to be the source k...Previously,troughs in continental faulted depressions were usually considered as a zone of hydrocarbon generation and expulsion rather than a zone for hydrocarbon accumulation.If they were confirmed to be the source kitchen,the possibility that they could constitute potential plays would be overlooked in the subsequent exploration program.Based on the hydrocarbon exploration practice of the Jizhong Depression and the Erlian Basin in the past several years,this paper discusses a new understanding that reservoir distribution is controlled by multiple factors and lithological accumulations are more likely to form in trough areas.It further documents the three main factors controlling the formation of large lithological hydrocarbon accumulations in trough areas.The paper also discusses the new concept that structural and lithological accumulations not only co-exist but also complement each other.We propose that fan-delta fronts on inverted steep slopes in troughs,delta fronts and sublacustrine fans on gentle slopes,channel sands along toes of fault scarps are favorable locations for discovery of new oil accumulations.The application of this concept has led to the discovery of several hundreds of million tonnes of oil in place in trough areas in the Jizhong Depression and the Erlian Basin.展开更多
西湖凹陷中央洼陷带发育一系列挤压大背斜,是寻找大中型油气田的勘探区域之一,一直以来以构造油气藏评价和研究为主。应用钻井、岩心、实验分析及地震资料,系统开展了中央洼陷带中部花港组岩性油气藏主控因素分析,建立了该地区岩性油气...西湖凹陷中央洼陷带发育一系列挤压大背斜,是寻找大中型油气田的勘探区域之一,一直以来以构造油气藏评价和研究为主。应用钻井、岩心、实验分析及地震资料,系统开展了中央洼陷带中部花港组岩性油气藏主控因素分析,建立了该地区岩性油气藏形成的地质模式,并预测了勘探有利区分布。研究结果表明,广覆式厚层平湖组煤系烃源岩发育为岩性油气藏的形成提供了雄厚的物质基础,辫状河三角洲—湖泊沉积背景下花港组多期水道与分流间湾交互发育有利于岩性尖灭型圈闭的形成,H1—H2层区域性盖层遮挡下可形成多套良好的储盖组合,早期NNE向油源断裂高效输导是岩性油气藏源外成藏的关键因素。大背斜北翼受北部物源控制,大背斜西翼受西部物源控制,分别发育多期水道尖灭;后期的龙井运动导致地层遭受强烈挤压,水道砂反转抬升形成上倾尖灭型岩性圈闭;同时,先存油源断层活化,沟通平湖组煤系烃源岩和上部水下分流河道砂体,最终形成多个岩性油气藏。综合分析认为,中央洼陷带中部A1、N1、Y1、N2等4个井区是H1—H2、H3—H5两套气层有利区叠合分布范围,面积达700 km 2,是最有利的勘探指向区。展开更多
基金supported by the National Basic Research Program of China (973 Program, Grant No. 2006CB202308)
文摘Located in the middle of the Tarim Basin, Tazhong is a typical area of compound reservoirs rich in oil and gas found in the Carboniferous, Silurian and Ordovician strata. The proved, probable and possible reserves （3P reserves） in the area amount to 5×108 tons, so it is of great significance to study the advances and problems in hydrocarbon exploration in the Tazhong area. On the basis of exploration history and analysis of scientific problems, we outline eight achievements： distribution characteristics of reservoirs, stages of reservoir formation, different sources of oil and gas and their respective contributions, the effective regional caprock and reservoir-caprock combinations dominating the vertical distribution of hydrocarbon reservoirs, the control of the Tazhong Palaeo-uplift on reservoir formation and establishing geologic models, structure balance belts influencing the reconstruction and residual potential of reservoirs after accumulation, the rules and mechanisms of fractures controlling oil and gas, and the types of favorable reservoirs and their characteristics of controlling oil and gas distribution. We further point out the main problems about the oil and gas exploration in the Tazhong area and put forward some relevant proposals.
文摘Previously,troughs in continental faulted depressions were usually considered as a zone of hydrocarbon generation and expulsion rather than a zone for hydrocarbon accumulation.If they were confirmed to be the source kitchen,the possibility that they could constitute potential plays would be overlooked in the subsequent exploration program.Based on the hydrocarbon exploration practice of the Jizhong Depression and the Erlian Basin in the past several years,this paper discusses a new understanding that reservoir distribution is controlled by multiple factors and lithological accumulations are more likely to form in trough areas.It further documents the three main factors controlling the formation of large lithological hydrocarbon accumulations in trough areas.The paper also discusses the new concept that structural and lithological accumulations not only co-exist but also complement each other.We propose that fan-delta fronts on inverted steep slopes in troughs,delta fronts and sublacustrine fans on gentle slopes,channel sands along toes of fault scarps are favorable locations for discovery of new oil accumulations.The application of this concept has led to the discovery of several hundreds of million tonnes of oil in place in trough areas in the Jizhong Depression and the Erlian Basin.
文摘西湖凹陷中央洼陷带发育一系列挤压大背斜,是寻找大中型油气田的勘探区域之一,一直以来以构造油气藏评价和研究为主。应用钻井、岩心、实验分析及地震资料,系统开展了中央洼陷带中部花港组岩性油气藏主控因素分析,建立了该地区岩性油气藏形成的地质模式,并预测了勘探有利区分布。研究结果表明,广覆式厚层平湖组煤系烃源岩发育为岩性油气藏的形成提供了雄厚的物质基础,辫状河三角洲—湖泊沉积背景下花港组多期水道与分流间湾交互发育有利于岩性尖灭型圈闭的形成,H1—H2层区域性盖层遮挡下可形成多套良好的储盖组合,早期NNE向油源断裂高效输导是岩性油气藏源外成藏的关键因素。大背斜北翼受北部物源控制,大背斜西翼受西部物源控制,分别发育多期水道尖灭;后期的龙井运动导致地层遭受强烈挤压,水道砂反转抬升形成上倾尖灭型岩性圈闭;同时,先存油源断层活化,沟通平湖组煤系烃源岩和上部水下分流河道砂体,最终形成多个岩性油气藏。综合分析认为,中央洼陷带中部A1、N1、Y1、N2等4个井区是H1—H2、H3—H5两套气层有利区叠合分布范围,面积达700 km 2,是最有利的勘探指向区。
