As the main factors affecting stable and high production and the production regularity of lacustrine shale oil are unclear,the theoretical understandings,key exploration and development technologies,development effect...As the main factors affecting stable and high production and the production regularity of lacustrine shale oil are unclear,the theoretical understandings,key exploration and development technologies,development effect and production regularity of lacustrine shale oil have been analyzed and summarized based on 700 m cores taken systematically from Paleogene Kong 2 Member of 4 wells in Cangdong sag,over 100000 analysis data and formation testing data.Three theoretical understandings on shale oil enrichment and high production have been reached:(1)High-quality shale with“three highs and one low”is the material base for shale oil enrichment.(2)Medium-slightly high thermal evolution degree is the favorable condition for shale oil enrichment.(3)Laminar felsic shale is the optimal shale layer for oil enrichment in semi-deep lake facies.Key exploration and development technologies such as shale oil enrichment layer and area evaluation and prediction,horizontal well pattern layout,shale oil reservoir fracturing,optimization of shale oil production regime have been established to support high and stable shale oil production.Under the guidance of these theoretical understandings and technologies,shale oil in Cangdong sag has achieved high and stable production,and 4 of them had the highest production of over 100 tons a day during formation testing.In particular,Well GY5-1-1 L had a daily oil production of 208 m^(3).By April,2022,the 28 wells combined have a stable oil production of 300–350 tons a day,and have produced 17.8×10^(4) t of oil cumulatively.It is found that the shale oil production of horizontal well declines exponentially in natural flow stage,and declines in step pattern and then tends stable in the artificial lift stage.Proportion of light hydrocarbons in produced shale oil is in positive correlation with daily oil production and decreases regularly during production test.展开更多
Compared with marine facies shale strata,lacustrine shale strata are more complicated in geological conditions,and thus more difficult to explore and develop.To realize economic exploration and development of lacustri...Compared with marine facies shale strata,lacustrine shale strata are more complicated in geological conditions,and thus more difficult to explore and develop.To realize economic exploration and development of lacustrine shale oil,the geological regularities of accumulation and high yield of retained movable petroleum in shale should be understood first.In this work,taking the shale strata of Kong 2 Member and Sha 3 Member in the Paleogene of Huanghua depression in the Bohai Bay Basin as examples,based on the previous joint analysis results of over ten thousand core samples and the latest oil testing,production test and geochemical data of more than 30 horizontal wells,accumulation conditions and models of retained movable petroleum in lacustrine shale were studied comprehensively.The study shows that at moderate organic matter abundance(with TOC from 2%to 4%),shale strata have the best match between oil content and brittleness,and thus are rich in oil and good in fracability.Moderate ancient lake basin size and moderate sediment supply intensity are the internal factors leading to best coupling of organic matter abundance and brittle mineral content in the shale formation.Moderate thermal evolution maturity of Ro of 0.7%–1.0%(at burial depth of 3200 to 4300 m)is the interval where oil generation from thermal evolution and oil adsorption by kerogen in shale layers match best,and retained movable petroleum is high in proportion.Moderate diagenetic evolution stage(3200 to 4300 m in the middle diagenetic stage A)is conducive to the formation of a large number of dissolved pores and organic matter pores,which provide storage space for shale oil enrichment.Moderate development degree of natural fractures(without damaging the shale oil roof and floor sealing conditions)is conducive to the storage,seepage and preservation of shale oil.The research results have overthrown the general understanding that high organic matter abundance,high maturity,and high development degree of natural fractures are conducive to shale oil enrichment,and have guided the comprehensive evaluation of shale oil and gas sweet spots and well deployment in the second member of the Kongdian Formation in the Cangdong sag and the Shahejie Formation in the Qikou sag.Industrial development of the shale oil in Kong 2 Member of the Cangdong sag has made major breakthrough,and important signs of shale oil have been found in Sha 3 Member of the Qikou sag,demonstrating huge exploration potential of lacustrine shale oil.展开更多
With the deterioration of global climate in recent years,climate change remains as a hot issue to which the international community pays close attention.2007 could be called the'Year of Climate Change'.In Apri...With the deterioration of global climate in recent years,climate change remains as a hot issue to which the international community pays close attention.2007 could be called the'Year of Climate Change'.In April,the United Nations Security Council held an open debate on climate change and international security for the first time,greatly enhancing the importance of展开更多
基金Supported by the National Key R&D Program of China(2020YFA0710504)Science and Technology Project of China National Petroleum Corporation(2021DQ0508)PetroChina Science and Technology Major Project(2019E-2602)。
文摘As the main factors affecting stable and high production and the production regularity of lacustrine shale oil are unclear,the theoretical understandings,key exploration and development technologies,development effect and production regularity of lacustrine shale oil have been analyzed and summarized based on 700 m cores taken systematically from Paleogene Kong 2 Member of 4 wells in Cangdong sag,over 100000 analysis data and formation testing data.Three theoretical understandings on shale oil enrichment and high production have been reached:(1)High-quality shale with“three highs and one low”is the material base for shale oil enrichment.(2)Medium-slightly high thermal evolution degree is the favorable condition for shale oil enrichment.(3)Laminar felsic shale is the optimal shale layer for oil enrichment in semi-deep lake facies.Key exploration and development technologies such as shale oil enrichment layer and area evaluation and prediction,horizontal well pattern layout,shale oil reservoir fracturing,optimization of shale oil production regime have been established to support high and stable shale oil production.Under the guidance of these theoretical understandings and technologies,shale oil in Cangdong sag has achieved high and stable production,and 4 of them had the highest production of over 100 tons a day during formation testing.In particular,Well GY5-1-1 L had a daily oil production of 208 m^(3).By April,2022,the 28 wells combined have a stable oil production of 300–350 tons a day,and have produced 17.8×10^(4) t of oil cumulatively.It is found that the shale oil production of horizontal well declines exponentially in natural flow stage,and declines in step pattern and then tends stable in the artificial lift stage.Proportion of light hydrocarbons in produced shale oil is in positive correlation with daily oil production and decreases regularly during production test.
基金Supported by the PetroChina Science and Technology Major Project(2019E-2601,2018E-11)
文摘Compared with marine facies shale strata,lacustrine shale strata are more complicated in geological conditions,and thus more difficult to explore and develop.To realize economic exploration and development of lacustrine shale oil,the geological regularities of accumulation and high yield of retained movable petroleum in shale should be understood first.In this work,taking the shale strata of Kong 2 Member and Sha 3 Member in the Paleogene of Huanghua depression in the Bohai Bay Basin as examples,based on the previous joint analysis results of over ten thousand core samples and the latest oil testing,production test and geochemical data of more than 30 horizontal wells,accumulation conditions and models of retained movable petroleum in lacustrine shale were studied comprehensively.The study shows that at moderate organic matter abundance(with TOC from 2%to 4%),shale strata have the best match between oil content and brittleness,and thus are rich in oil and good in fracability.Moderate ancient lake basin size and moderate sediment supply intensity are the internal factors leading to best coupling of organic matter abundance and brittle mineral content in the shale formation.Moderate thermal evolution maturity of Ro of 0.7%–1.0%(at burial depth of 3200 to 4300 m)is the interval where oil generation from thermal evolution and oil adsorption by kerogen in shale layers match best,and retained movable petroleum is high in proportion.Moderate diagenetic evolution stage(3200 to 4300 m in the middle diagenetic stage A)is conducive to the formation of a large number of dissolved pores and organic matter pores,which provide storage space for shale oil enrichment.Moderate development degree of natural fractures(without damaging the shale oil roof and floor sealing conditions)is conducive to the storage,seepage and preservation of shale oil.The research results have overthrown the general understanding that high organic matter abundance,high maturity,and high development degree of natural fractures are conducive to shale oil enrichment,and have guided the comprehensive evaluation of shale oil and gas sweet spots and well deployment in the second member of the Kongdian Formation in the Cangdong sag and the Shahejie Formation in the Qikou sag.Industrial development of the shale oil in Kong 2 Member of the Cangdong sag has made major breakthrough,and important signs of shale oil have been found in Sha 3 Member of the Qikou sag,demonstrating huge exploration potential of lacustrine shale oil.
文摘With the deterioration of global climate in recent years,climate change remains as a hot issue to which the international community pays close attention.2007 could be called the'Year of Climate Change'.In April,the United Nations Security Council held an open debate on climate change and international security for the first time,greatly enhancing the importance of
