Ramp-type bioherm is geologically characterized by lateral migration,small size and discrete distribution.The fine bioherm description is of high difficulty and the benefit development of bioherm gas reservoirs can be...Ramp-type bioherm is geologically characterized by lateral migration,small size and discrete distribution.The fine bioherm description is of high difficulty and the benefit development of bioherm gas reservoirs can be hardly realized.To solve these difficulties,this paper put forward a new bioherm identification method based on well-seismic combination after cognizing the geological characteristics of ramp-type bioherms deeply.And this new method plays a successful role in guiding the drilling ofWell Y012-X16 in the mode of“two bioherms in one well”in the Damaoping Block of eastern Sichuan Basin.High-yield industrial gas flow of 113.65×10^(4)m^(3)/d is obtained during the test and great new progress is achieved in the exploration of bioherm gas reservoirs.And the following research results were obtained.First,the degree of slope at the marginal platform slope of ramp-type bioherm is only 2°-4°.The migration and evolution laws of bioherms are mainly controlled by the change of paleogeomorphology and sea level.As a result,small bioherms of multiple rows and multiple periods are formed and the gas-water contact of ramp-type bioherm gas reservoir is not united,presenting the characteristics of“one bioherm,one reservoir”.The gas bearing property is good at the top of the bioherm.The overall gas bearing property is poorer in the early bioherm of the second member of Upper Permian Changxing Formation and better in the late bioherm of the third member of Changxing Formation.Second,a new bioherm identification method with“double-high”integrated seismic processing technology,data driven“box-shaped volume”perspective technology,remaining thickness method based sedimentary paleogeomorphology restoration technology and three-dimensional visualization technology as the core is developed innovatively,which provides the fine description of ramp-type small bioherms in the three dimensional space.Third,based on the application of the new bioherm identification method,the distribution detail of the bioherms in the Damaoping Block is clarified,the development mode of“two bioherms in onewell”for long horizontal sections is established and a PetroChina's new record of bioherm reservoir drilling length is set up in Well Y012-X16,which launches a new means to the benefit development of small bioherm group.Fourth,it is predicted that a number of bioherm development areas can be newly increased in the Damaoping Block,which can provide the supplement productivity of 100×10^(4)m^(3)/d for the development of gas reservoirs,so their natural gas exploration and development potential is huge.In conclusion,the fine description technologies for ramp-type small bioherms are conducive to the identification of ramp-type small bioherm group and the efficient exploration and development of bioherm gas reservoirs in the Sichuan Basin.展开更多
In this paper, the morphology, sedimentary structure, bioherm--building mollusk assem-blages and their growing and piling-up models of modern oyster bioherms in the estuariesof the Zimaigou and Xiaoqing Rivers are des...In this paper, the morphology, sedimentary structure, bioherm--building mollusk assem-blages and their growing and piling-up models of modern oyster bioherms in the estuariesof the Zimaigou and Xiaoqing Rivers are described and expounded, the environmentalconditions for the development of oyster bioherms, such as the dynamical geomorphicbackground, water depth, hydrodynamic factors and ecological conditions in the estuaries,are analyzed, the relationship of the successively seaward migrating of oyster biohermswith average annual sea-level changes and the erosion--accretion processes in the estuariesare probed and explained, and the geological significance of oyster bioherms in the studyof Quaternary marine environmental evolution is presented.展开更多
It is known from macrocomparisons and microresearches of bioherm reservoirs in main sedimentary basins of the South China Sea through deep-water petroleum explorations and by means of 2D/3D seismic data and a whole-co...It is known from macrocomparisons and microresearches of bioherm reservoirs in main sedimentary basins of the South China Sea through deep-water petroleum explorations and by means of 2D/3D seismic data and a whole-coring core from the Xisha Islands that there are great dif- ferences between deep-sea oil and gas fields in the world and those in the South China Sea, as reservoir systems of the former are mainly clastic rocks, whereas the latter have organic reefs that act as reser- voirs of their largest oil and gas fields, which are represented by large Liuhua 11-1 reef oilfield in the north and super-large L reef gas field in the south of the South China Sea. Therefore, it is of great significance to study deep-water hioherm reservoirs in the South China Sea. Comparisons of organic reefs in the four large islands of the South China Sea give evidences that such reefs in main sedimentary basins came into being during Cenozoic, especially in Neogene, and mainly occur as tower （point） reef, massive reef, platform-edge reef, and patch reef in shape, which show different reservoir physical properties and seismic reflection configurations and make up carbonate rock-bioherm formations in the island reef and sedimentary basin areas. Generally, the south and north parts differ from the east and the west of the South China Sea in geologic conditions, as their corresponding continental shelf/island shelf areas are relatively wide/ narrow, large stream current systems are well developed/not so well developed, and terrigenous sediments are relatively sufficient/insufficient. The southeast and south parts of the South China Sea had organic reefs built up earlier than the north and the reef building mainly took place in Neogene; these Neogene organic reefs all be- long to plant algal reef rocks. Liuhua oilfield in the Pearl River Mouth basin is found to mainly have red algal bindstone, Malampaya reef in the northern Palawan basin is rich in both red algal bind- stone and green algal reef segmented rock, and especially Miocene red algal framestone and green algal segmented rock are discovered in the Xisha Islands. These algal reefs created different sedimentary mi- crofacies as well as various rock structures and types, and through recent researches on the mechanism of dolomitization, freshwater dolomite was discovered and grouped under products from dolomitization in mixed water that was regression reefal dolomite of good reservoir properties.展开更多
Located in the Sichuan Basin,the Yuanba Gasfield is the deepest high-sulfur carbonate gasfield among those discovered in the world.Its biohermal gas reservoir of the Upper Permian Changxing Fm is characterized by ultr...Located in the Sichuan Basin,the Yuanba Gasfield is the deepest high-sulfur carbonate gasfield among those discovered in the world.Its biohermal gas reservoir of the Upper Permian Changxing Fm is characterized by ultra depth,multi-stage small and scattered reef,thin reservoir,poor physical properties,strong heterogeneity,complexfluid distribution,and low production of vertical wells.The development of the bio-hermal gas reservoir is subject to many difficulties.For example,it is necessary to deepen the studies on timeespace distribution laws of reef dolomite reservoirs;it is difficult to characterize small reefs precisely and predict thin reservoirs quantitatively;the deployment and optimization design of horizontal wells are influenced by multiple factors;and the difficulty for horizontal wells with long horizontal sections to run through high-quality thin reservoirs is high.In order to develop the Yuanba Gasfield efficiently,therefore,it is necessary to carry out a series of technical researches on the distribution laws and development models of biohermal reservoirs,precise characterization of small reefs,quantitative pre-diction of thin reservoirs,optimization design of horizontal wells in banded small reef gas reservoirs,and real-time trajectory optimization and adjustment of horizontal wells in ultra-deep thin reservoirs.These research results provide a powerful support for the development and con-struction of the Yuanba Gasfield.Based on these technologies,China'sfirst ultra-deep high-sulfur large biohermal gasfield was built with a mixed gas annual production capacity of 40108 m3.The successful commissioning of the Yuanba Gasfield lays a basis for the leading position of China in thefield of high-sulfur gasfield development.In addition,it is of great significance to the long-term stable gas supply in 70 cities of six provinces and two municipalities along the“Sichuan-to-East China Gas Transmission Pipeline”,as well as to the industrial structure adjustment in centralewestern China and the economic development along the Yangtze River.展开更多
The growth process, palaeoecological features and the function of organisms in reef-building of the Jukoupu bioherm in Hunan are discussed in detail. The bioherm is divided into 10 microfacies. Organisms are very abun...The growth process, palaeoecological features and the function of organisms in reef-building of the Jukoupu bioherm in Hunan are discussed in detail. The bioherm is divided into 10 microfacies. Organisms are very abundant in the reef. Thirty-two genera Belonging to 7 phyla have been recognized. They make up 5 communities composed mainly of stromatopoids, Corals and algae, each of which has its own salient ecological features. An analysis of all communities shows that the organic functions are very complex. The same organisms may possess diverse functions simultaneously as the reef growth enters the late stage. The growth process of the reef may involve five stages' (l)biostrome stage, (2) stabilization stage, (3) frame-type reef-building stage, (4) binding and covering-type reef-building stage, and (5) baffle- type reef -building stage.展开更多
Confirming thick hydrocarbon generation center and discovering thick porous reservoirs are two key factors to start the Permian gas exploration of the Western Sichuan Depression.In this paper,the Sinian-Cambrian struc...Confirming thick hydrocarbon generation center and discovering thick porous reservoirs are two key factors to start the Permian gas exploration of the Western Sichuan Depression.In this paper,the Sinian-Cambrian structures of this area were studied by adopting the layer-flattening technology and the Lower Paleozoic thickness map was prepared in order to describe the Permian hydrocarbon generation center.Then,combined with seismic facies analysis and field outcrop bioherm discovery,the distribution of Middle Permian reef flat reservoirs were predicted.Finally,the favorable conditions for reef flat reservoir dolomitization were analyzed based on fault features.The study indicates that:(1)Sinian top represents a huge depression in the profile flatted by the reflecting interface of Permian bottom,with normal faults filled by thick Lower Paleozoic sediments at both sides,revealing that a aulacogen formed during the Khanka taphrogeny exists in the Western Sichuan Depression,where very thick Cambrian strata may contain hydrocarbon generation center,making Permian strata have the material conditions for the formation of large gas pools;(2)the Middle Permian strata in the Western Sichuan Depression exhibit obvious abnormal response in reef flat facies,where three large abnormal bands are developed,which are predicted as bioherm complex combined with the Middle Permian bioherm outcrop discoveries in surface;and(3)deep and large extensional faults are developed in reef flat margin,manifesting as favorable conditions for the development of dolomite reservoirs.The results show that the Middle Permian traps in the Western Sichuan Depression contain resources up to 7400×10^(8)m^(3),showing significant natural gas exploration prospects.By far,one risk exploration well has been deployed.展开更多
Located in the Sichuan Basin,the Yuanba Gasfield is the deepest marine sour gasfield among those developed in China so far.Its biohermal gas reservoir of the Upper Permian Changxing Fm is characterized by ultra depth,...Located in the Sichuan Basin,the Yuanba Gasfield is the deepest marine sour gasfield among those developed in China so far.Its biohermal gas reservoir of the Upper Permian Changxing Fm is characterized by ultra depth,high content of hydrogen sulfide,mediumelow porosity and permeability,and small reservoir thickness.Economic evaluation on it shows that horizontal well drilling is the only way to develop this gas reservoir efficiently and to reduce the total development investment.At present,the petroleum engineering technology for this type of ultra-deep sour gas reservoir is less applied in the world,so an ultra-deep horizontal well is subject to a series of petroleum engineering technology difficulties,such as safe and fast well drilling and completion,mud logging,well logging,downhole operation,safety and environmental protection.Based on the successful development experience of the Puguang Gasfield,therefore,Sinopec Southwest Petroleum Engineering Co.,Ltd.took the advantage of integrated engineering geology method to carry out specific technical research and perform practice diligently for 7 years.As a result,18 key items of technologies for ultra-deep sour gas reservoirs were developed,including horizontal-well drilling speed increasing technology,horizontal-well mud logging and well logging technology,downhole operation technology,and safety and environmental protection technology.These technologies were applied in 40 wells during thefirst and second phases of productivity construction of the Yuanba Gasfield.All the 40 wells have been built into commercial gas wells,and the productivity construction goal of 3.4 billion m3 purified gas has also been achieved.These petroleum engineering technologies for ultra-deep sour gasfields play a reference role in exploring and developing similar gas reservoirs at home and abroad.展开更多
The gas-water relationship in the Permian and Triassic biohermal beach reservoirs in the Sichuan Basin is complex,which results in a low drilling success rate and leads to sidetracking or even secondary sidetracking i...The gas-water relationship in the Permian and Triassic biohermal beach reservoirs in the Sichuan Basin is complex,which results in a low drilling success rate and leads to sidetracking or even secondary sidetracking in some wells.Therefore,high-precision gas-water identification is the key to the drilling success rate.In this paper,the biohermal gas reservoir in the T work area of the eastern Sichuan Basin was taken as an example.Firstly,the frequency information of seismic data sensitive to gas bearing properties was exploited sufficiently by taking the deep/shallow resistivity information which is sensitive to gas-water discrimination as a constraint and the nonlinear algorithm as a bridge.Then,combined with the information of full-band relative wave impedance,a nonlinear mapping relationship between the logarithmic difference curve of deep/shallow resistivity and the seismic waveform was established,and the gas bearing properties of the reservoir were predicted.In this way,a post-stack gas prediction method was developed.Finally,field application and effect analysis were carried out.And the following research results were obtained.First,gas layer information indicated by deep/shallow resistivity not only has the function of verification well,but can be extracted as a priori information for the constraint of seismic data.Second,frequency division information increases the mapping relationship between multi-frequency data volume and the logarithmic difference of deep/shallow resistivity,and the colored inversion,as the more reasonable full-band relative-wave impedance seismic data,is more conducive to gas and water identification.Third,based on the nonlinear mapping relationship,the data volume of a gas sensitive factor was obtained,and the range of gas layers was quantified,so as to realize the quantitative characterization of gas bearing properties.It is concluded that the gas prediction technology developed in this paper provides an effective and practical post-stack gas prediction method,and its field application effect is good,presenting wide popularization and application prospects.展开更多
With oil and gas exploration transferring to deeper and more ancient marine strata,more researches have been conducted about the Meso—Neoproterozoic and Cambrian microbial carbonate rocks by petroleum geologists.The ...With oil and gas exploration transferring to deeper and more ancient marine strata,more researches have been conducted about the Meso—Neoproterozoic and Cambrian microbial carbonate rocks by petroleum geologists.The Cambrian deposits experienced the first transgression of the Paleozoic,with shallow marine facies depositing in most areas,which are favorable for different kinds of biological reproduction.The Lower Cambrian in Beijing area is lithologically dominated by purple red shales interbedded with limestones,the Middle Cambrian is mainly composed of thick oolitic limestones,and the Upper Cambrian consists of thin limestones and flat-pebble conglomerates.Two beds of microbial carbonate rocks were discovered in the Cambrian outcrops in the vicinity of Beijing.One is from the Zhangxia Formation of Middle Cambrian,and the other is from the Gushan Formation of Upper Cambrian.The microbialites are characterized by combination of multiple stromatolites forming different bioherms.The bioherms are mostly in oval shape and with different sizes,which are 3-4 m long,and 1-3 m high.The surrounding strata beneath the bioherms are oolitic limestones.A central core of flat-pebble conglomerates occurred within each bioherm.Wavy or columnar stromatolites grow on the basis of flat-pebble conglomerates,with dentate erosional surfaces.The bioherm carbonate rocks are interpreted as products from a deep ramp sedimentary environment where potential oil and gas reservoirs can be found.The analysis of sedimentological characteristics of bioherm carbonate rocks and its lithofacies palaeogeography has significant implication for petroleum exploration.Research on geological record of microbialites is beneficial to investigating the Earth evolution,biodiversity,palaeoenvironment and palaeoclimate change,as well as biological extinction event during geological transitions.It also gives warning to human beings of modern biological crisis.展开更多
基金Project supported by the National Major Science and Technology Project“Demonstrative project of large carbonate gas field development in Sichuan Basin”(No.2016ZX05052)PetroChina Major Science and Technology Project“Research and application of key technology for a productivity of 30 billion cubic meters in Southwest Oil and Gas Field”(No.2016E-06).
文摘Ramp-type bioherm is geologically characterized by lateral migration,small size and discrete distribution.The fine bioherm description is of high difficulty and the benefit development of bioherm gas reservoirs can be hardly realized.To solve these difficulties,this paper put forward a new bioherm identification method based on well-seismic combination after cognizing the geological characteristics of ramp-type bioherms deeply.And this new method plays a successful role in guiding the drilling ofWell Y012-X16 in the mode of“two bioherms in one well”in the Damaoping Block of eastern Sichuan Basin.High-yield industrial gas flow of 113.65×10^(4)m^(3)/d is obtained during the test and great new progress is achieved in the exploration of bioherm gas reservoirs.And the following research results were obtained.First,the degree of slope at the marginal platform slope of ramp-type bioherm is only 2°-4°.The migration and evolution laws of bioherms are mainly controlled by the change of paleogeomorphology and sea level.As a result,small bioherms of multiple rows and multiple periods are formed and the gas-water contact of ramp-type bioherm gas reservoir is not united,presenting the characteristics of“one bioherm,one reservoir”.The gas bearing property is good at the top of the bioherm.The overall gas bearing property is poorer in the early bioherm of the second member of Upper Permian Changxing Formation and better in the late bioherm of the third member of Changxing Formation.Second,a new bioherm identification method with“double-high”integrated seismic processing technology,data driven“box-shaped volume”perspective technology,remaining thickness method based sedimentary paleogeomorphology restoration technology and three-dimensional visualization technology as the core is developed innovatively,which provides the fine description of ramp-type small bioherms in the three dimensional space.Third,based on the application of the new bioherm identification method,the distribution detail of the bioherms in the Damaoping Block is clarified,the development mode of“two bioherms in onewell”for long horizontal sections is established and a PetroChina's new record of bioherm reservoir drilling length is set up in Well Y012-X16,which launches a new means to the benefit development of small bioherm group.Fourth,it is predicted that a number of bioherm development areas can be newly increased in the Damaoping Block,which can provide the supplement productivity of 100×10^(4)m^(3)/d for the development of gas reservoirs,so their natural gas exploration and development potential is huge.In conclusion,the fine description technologies for ramp-type small bioherms are conducive to the identification of ramp-type small bioherm group and the efficient exploration and development of bioherm gas reservoirs in the Sichuan Basin.
文摘In this paper, the morphology, sedimentary structure, bioherm--building mollusk assem-blages and their growing and piling-up models of modern oyster bioherms in the estuariesof the Zimaigou and Xiaoqing Rivers are described and expounded, the environmentalconditions for the development of oyster bioherms, such as the dynamical geomorphicbackground, water depth, hydrodynamic factors and ecological conditions in the estuaries,are analyzed, the relationship of the successively seaward migrating of oyster biohermswith average annual sea-level changes and the erosion--accretion processes in the estuariesare probed and explained, and the geological significance of oyster bioherms in the studyof Quaternary marine environmental evolution is presented.
基金supported by the National Natural Science Foundation of China (Nos.49206061 and 41106064)the Major National Oil and Gas Special Programs (Nos.2008ZX05025-03 and 2011ZX05025-002)the 973 Program of China (No.2012CB956004)
文摘It is known from macrocomparisons and microresearches of bioherm reservoirs in main sedimentary basins of the South China Sea through deep-water petroleum explorations and by means of 2D/3D seismic data and a whole-coring core from the Xisha Islands that there are great dif- ferences between deep-sea oil and gas fields in the world and those in the South China Sea, as reservoir systems of the former are mainly clastic rocks, whereas the latter have organic reefs that act as reser- voirs of their largest oil and gas fields, which are represented by large Liuhua 11-1 reef oilfield in the north and super-large L reef gas field in the south of the South China Sea. Therefore, it is of great significance to study deep-water hioherm reservoirs in the South China Sea. Comparisons of organic reefs in the four large islands of the South China Sea give evidences that such reefs in main sedimentary basins came into being during Cenozoic, especially in Neogene, and mainly occur as tower （point） reef, massive reef, platform-edge reef, and patch reef in shape, which show different reservoir physical properties and seismic reflection configurations and make up carbonate rock-bioherm formations in the island reef and sedimentary basin areas. Generally, the south and north parts differ from the east and the west of the South China Sea in geologic conditions, as their corresponding continental shelf/island shelf areas are relatively wide/ narrow, large stream current systems are well developed/not so well developed, and terrigenous sediments are relatively sufficient/insufficient. The southeast and south parts of the South China Sea had organic reefs built up earlier than the north and the reef building mainly took place in Neogene; these Neogene organic reefs all be- long to plant algal reef rocks. Liuhua oilfield in the Pearl River Mouth basin is found to mainly have red algal bindstone, Malampaya reef in the northern Palawan basin is rich in both red algal bind- stone and green algal reef segmented rock, and especially Miocene red algal framestone and green algal segmented rock are discovered in the Xisha Islands. These algal reefs created different sedimentary mi- crofacies as well as various rock structures and types, and through recent researches on the mechanism of dolomitization, freshwater dolomite was discovered and grouped under products from dolomitization in mixed water that was regression reefal dolomite of good reservoir properties.
基金supported by the National Science and Technology Major Project in the 13th Five-Year Plan"High-efficiency development of ultra-deep bio-herm gas reservoirs with bottom water"(No.:2016ZX05017-005).
文摘Located in the Sichuan Basin,the Yuanba Gasfield is the deepest high-sulfur carbonate gasfield among those discovered in the world.Its biohermal gas reservoir of the Upper Permian Changxing Fm is characterized by ultra depth,multi-stage small and scattered reef,thin reservoir,poor physical properties,strong heterogeneity,complexfluid distribution,and low production of vertical wells.The development of the bio-hermal gas reservoir is subject to many difficulties.For example,it is necessary to deepen the studies on timeespace distribution laws of reef dolomite reservoirs;it is difficult to characterize small reefs precisely and predict thin reservoirs quantitatively;the deployment and optimization design of horizontal wells are influenced by multiple factors;and the difficulty for horizontal wells with long horizontal sections to run through high-quality thin reservoirs is high.In order to develop the Yuanba Gasfield efficiently,therefore,it is necessary to carry out a series of technical researches on the distribution laws and development models of biohermal reservoirs,precise characterization of small reefs,quantitative pre-diction of thin reservoirs,optimization design of horizontal wells in banded small reef gas reservoirs,and real-time trajectory optimization and adjustment of horizontal wells in ultra-deep thin reservoirs.These research results provide a powerful support for the development and con-struction of the Yuanba Gasfield.Based on these technologies,China'sfirst ultra-deep high-sulfur large biohermal gasfield was built with a mixed gas annual production capacity of 40108 m3.The successful commissioning of the Yuanba Gasfield lays a basis for the leading position of China in thefield of high-sulfur gasfield development.In addition,it is of great significance to the long-term stable gas supply in 70 cities of six provinces and two municipalities along the“Sichuan-to-East China Gas Transmission Pipeline”,as well as to the industrial structure adjustment in centralewestern China and the economic development along the Yangtze River.
文摘The growth process, palaeoecological features and the function of organisms in reef-building of the Jukoupu bioherm in Hunan are discussed in detail. The bioherm is divided into 10 microfacies. Organisms are very abundant in the reef. Thirty-two genera Belonging to 7 phyla have been recognized. They make up 5 communities composed mainly of stromatopoids, Corals and algae, each of which has its own salient ecological features. An analysis of all communities shows that the organic functions are very complex. The same organisms may possess diverse functions simultaneously as the reef growth enters the late stage. The growth process of the reef may involve five stages' (l)biostrome stage, (2) stabilization stage, (3) frame-type reef-building stage, (4) binding and covering-type reef-building stage, and (5) baffle- type reef -building stage.
基金Supported by National Science and Technology Major Project“Clastic reservoir identification and prediction in the Sichuan Basin”(Grant No.2008ZX05002-004-003).
文摘Confirming thick hydrocarbon generation center and discovering thick porous reservoirs are two key factors to start the Permian gas exploration of the Western Sichuan Depression.In this paper,the Sinian-Cambrian structures of this area were studied by adopting the layer-flattening technology and the Lower Paleozoic thickness map was prepared in order to describe the Permian hydrocarbon generation center.Then,combined with seismic facies analysis and field outcrop bioherm discovery,the distribution of Middle Permian reef flat reservoirs were predicted.Finally,the favorable conditions for reef flat reservoir dolomitization were analyzed based on fault features.The study indicates that:(1)Sinian top represents a huge depression in the profile flatted by the reflecting interface of Permian bottom,with normal faults filled by thick Lower Paleozoic sediments at both sides,revealing that a aulacogen formed during the Khanka taphrogeny exists in the Western Sichuan Depression,where very thick Cambrian strata may contain hydrocarbon generation center,making Permian strata have the material conditions for the formation of large gas pools;(2)the Middle Permian strata in the Western Sichuan Depression exhibit obvious abnormal response in reef flat facies,where three large abnormal bands are developed,which are predicted as bioherm complex combined with the Middle Permian bioherm outcrop discoveries in surface;and(3)deep and large extensional faults are developed in reef flat margin,manifesting as favorable conditions for the development of dolomite reservoirs.The results show that the Middle Permian traps in the Western Sichuan Depression contain resources up to 7400×10^(8)m^(3),showing significant natural gas exploration prospects.By far,one risk exploration well has been deployed.
基金supported by the Sinopec Technical Development Project"Pilot Test for Ultra-deep Horizontal Well Acid Fracturing Technology for Marine Reservoirs in Yuanba Gasfield"(No.:GJ-258-1254)Sinopec Group Technical Application Project“Optimization Design of Teas for High-presure High-yield Sour Gas Wells in the Northeaster Sichuan Basin”(No.:JPO8001).
文摘Located in the Sichuan Basin,the Yuanba Gasfield is the deepest marine sour gasfield among those developed in China so far.Its biohermal gas reservoir of the Upper Permian Changxing Fm is characterized by ultra depth,high content of hydrogen sulfide,mediumelow porosity and permeability,and small reservoir thickness.Economic evaluation on it shows that horizontal well drilling is the only way to develop this gas reservoir efficiently and to reduce the total development investment.At present,the petroleum engineering technology for this type of ultra-deep sour gas reservoir is less applied in the world,so an ultra-deep horizontal well is subject to a series of petroleum engineering technology difficulties,such as safe and fast well drilling and completion,mud logging,well logging,downhole operation,safety and environmental protection.Based on the successful development experience of the Puguang Gasfield,therefore,Sinopec Southwest Petroleum Engineering Co.,Ltd.took the advantage of integrated engineering geology method to carry out specific technical research and perform practice diligently for 7 years.As a result,18 key items of technologies for ultra-deep sour gas reservoirs were developed,including horizontal-well drilling speed increasing technology,horizontal-well mud logging and well logging technology,downhole operation technology,and safety and environmental protection technology.These technologies were applied in 40 wells during thefirst and second phases of productivity construction of the Yuanba Gasfield.All the 40 wells have been built into commercial gas wells,and the productivity construction goal of 3.4 billion m3 purified gas has also been achieved.These petroleum engineering technologies for ultra-deep sour gasfields play a reference role in exploring and developing similar gas reservoirs at home and abroad.
基金Project supported by the National Key R&D Program of China“Research on ultra-deep gravity,magnetic,electrical and seismic exploration technology”(No.:2016YFC0601100).
文摘The gas-water relationship in the Permian and Triassic biohermal beach reservoirs in the Sichuan Basin is complex,which results in a low drilling success rate and leads to sidetracking or even secondary sidetracking in some wells.Therefore,high-precision gas-water identification is the key to the drilling success rate.In this paper,the biohermal gas reservoir in the T work area of the eastern Sichuan Basin was taken as an example.Firstly,the frequency information of seismic data sensitive to gas bearing properties was exploited sufficiently by taking the deep/shallow resistivity information which is sensitive to gas-water discrimination as a constraint and the nonlinear algorithm as a bridge.Then,combined with the information of full-band relative wave impedance,a nonlinear mapping relationship between the logarithmic difference curve of deep/shallow resistivity and the seismic waveform was established,and the gas bearing properties of the reservoir were predicted.In this way,a post-stack gas prediction method was developed.Finally,field application and effect analysis were carried out.And the following research results were obtained.First,gas layer information indicated by deep/shallow resistivity not only has the function of verification well,but can be extracted as a priori information for the constraint of seismic data.Second,frequency division information increases the mapping relationship between multi-frequency data volume and the logarithmic difference of deep/shallow resistivity,and the colored inversion,as the more reasonable full-band relative-wave impedance seismic data,is more conducive to gas and water identification.Third,based on the nonlinear mapping relationship,the data volume of a gas sensitive factor was obtained,and the range of gas layers was quantified,so as to realize the quantitative characterization of gas bearing properties.It is concluded that the gas prediction technology developed in this paper provides an effective and practical post-stack gas prediction method,and its field application effect is good,presenting wide popularization and application prospects.
基金financed by the China National Science Foundation(research project No. 2016ZX05004-001)support from RIPED and related oilfield companies
文摘With oil and gas exploration transferring to deeper and more ancient marine strata,more researches have been conducted about the Meso—Neoproterozoic and Cambrian microbial carbonate rocks by petroleum geologists.The Cambrian deposits experienced the first transgression of the Paleozoic,with shallow marine facies depositing in most areas,which are favorable for different kinds of biological reproduction.The Lower Cambrian in Beijing area is lithologically dominated by purple red shales interbedded with limestones,the Middle Cambrian is mainly composed of thick oolitic limestones,and the Upper Cambrian consists of thin limestones and flat-pebble conglomerates.Two beds of microbial carbonate rocks were discovered in the Cambrian outcrops in the vicinity of Beijing.One is from the Zhangxia Formation of Middle Cambrian,and the other is from the Gushan Formation of Upper Cambrian.The microbialites are characterized by combination of multiple stromatolites forming different bioherms.The bioherms are mostly in oval shape and with different sizes,which are 3-4 m long,and 1-3 m high.The surrounding strata beneath the bioherms are oolitic limestones.A central core of flat-pebble conglomerates occurred within each bioherm.Wavy or columnar stromatolites grow on the basis of flat-pebble conglomerates,with dentate erosional surfaces.The bioherm carbonate rocks are interpreted as products from a deep ramp sedimentary environment where potential oil and gas reservoirs can be found.The analysis of sedimentological characteristics of bioherm carbonate rocks and its lithofacies palaeogeography has significant implication for petroleum exploration.Research on geological record of microbialites is beneficial to investigating the Earth evolution,biodiversity,palaeoenvironment and palaeoclimate change,as well as biological extinction event during geological transitions.It also gives warning to human beings of modern biological crisis.
