平方公里阵列(Square Kilometer Array,SKA)射电望远镜的低频阵列SKA1-LOW将承担宇宙再电离(Epoch of Reionization,EoR)等关键科学研究任务.频率平均计算可以有效降低数据量、提高成像灵敏度,但所带来的“带宽效应”对SKA1-LOW成像的...平方公里阵列(Square Kilometer Array,SKA)射电望远镜的低频阵列SKA1-LOW将承担宇宙再电离(Epoch of Reionization,EoR)等关键科学研究任务.频率平均计算可以有效降低数据量、提高成像灵敏度,但所带来的“带宽效应”对SKA1-LOW成像的影响还缺少定量的分析和研究.采用仿真方法,对频率平均效应进行了深入研究.通过对SKA1-LOW进行全阵列仿真、频率平均和洁化处理,系统对比了平均多频道及单频道情况下的复原图,分析两者相减后的残差图.深入分析了频率平均对观测源强度的影响,得到峰值强度在不同成像权重时随平均频道数变化的定量结果,为SKA1-LOW实际观测中选择合适的频率平均频道数提供了参考依据,对于SKA1-LOW开展科学研究具有重要的价值.展开更多
The reservoir space,types and distribution characteristics of karst carbonate gas reservoirs in the fourth member of Sinian Dengying Formation(Deng 4 Member)in central Sichuan Basin are analyzed based on the drilling,...The reservoir space,types and distribution characteristics of karst carbonate gas reservoirs in the fourth member of Sinian Dengying Formation(Deng 4 Member)in central Sichuan Basin are analyzed based on the drilling,logging and seismic data.A development model of karst reservoirs is constructed to support the high-efficiency development of gas pools.The research shows that the reservoirs in Deng 4 Member have mainly small-scale karst vugs and fractures as storage space,and can be divided into three types,fracture-vug,pore-vug and pore types.The development patterns of the karst reservoirs are determined.On the plane,the karst layers increase from 65 m to 170 m in thickness from the karst platform to the karst slope,and the high-quality reservoirs increase from 25.0 m to 42.2 m in thickness;vertically,the reservoirs at the top of Deng 4 Member appear in multiple layers,and show along-bedding and along fracture dissolution characteristics.The reservoirs at the bottom are characterized by the dissolution parallel to the water level during the karstification period,and have 3-5 large-scale fracture-cave systems.Based on the reservoir development characteristics and the genetic mechanism,three types of reservoir development models of karst reservoir are established,i.e.,bed-dissolved body,fracture-dissolved body and paleohorizon-dissolved body.The construction of karst reservoir development models and seismic response characteristics of the three types of reservoirs can provide parameter for well placement and trajectory design,and substantially improve productivity and development indices of individual wells and gas reservoirs.The designed production capacity of the gas reservoir has enhanced from the initial 3.6 billion to 6 billion cubic meters,making the profit of the reservoir development increase noticeably.展开更多
The Sinian Dengying Formation gas reservoir in the Anyue gas field of the Sichuan Basin is an ultra-deep ancient dolomite karst gas reservoir,whose development is of high difficulty,for the reservoir is thin and scatt...The Sinian Dengying Formation gas reservoir in the Anyue gas field of the Sichuan Basin is an ultra-deep ancient dolomite karst gas reservoir,whose development is of high difficulty,for the reservoir is thin and scattered with strong heterogeneity and is overall characterized by low porosity and low permeability.In order to provide support for the large-scale productivity construction of the gas reservoir of the fourth member of Dengying Formation(Deng 4 Member)in the marginal platform belt of the Anyue gas field,this paper carries out multi-discipline comprehensive researches on the technical bottlenecks based on the geological characteristics of the gas reservoir.In addition,the targeted key technologies for the efficient development of gas reservoirs were developed in the mode of“simultaneous research,application and improvement”.And the following research results are obtained.First,based on the modeling technology of fracturedevuggy dolomite karst reservoirs,accurate modeling of karst reservoirs is realized.Late actual drilling results show that the model's coincidence rate is increased from 63.0% to 90.7% and the“transparency”of gas reservoirs is achieved.Second,based on the reserve mobility evaluation technology of lowporosity and highly-heterogeneous karst reservoirs,the recovery factors of different reservoirs are determined.And consequently,the lower limit of well-controlled reserves and radius for the efficient development of different reservoirs are obtained and type Ⅰ and Ⅱ reservoirs are selected as the main development targets.Third,based on the development optimization design technology of highly-heterogeneous karst gas reservoirs,it is recommended to apply highly-deviated wells(the maximum deviation angle of 75°-84°)in the situations with multiple reservoirs crossed and superimposed.If type Ⅰ and Ⅱ reservoirs are developed intensively,it is recommended to adopt horizontal well drilling with a horizontal section of 800-1100 m.What's more,the reasonable well spacing in type Ⅰ and Ⅱ reservoirs shall be 1.6-3.3 km and 0.9-1.4 km,respectively.Fourth,based on the distinguished drilling technology of highly-deviated wells/horizontal wells in deep carbonate rocks,the fault complexity ratio is decreased from 20.7% to 4.9%,so safe and fast drilling and completion of highly-deviated wells/horizontal wells is realized and well control risks are diminished.What's more,the drilling rates of type Ⅰ and Ⅱ reservoirs are increased from 24.2% to 87.3%,indicating an effective improvement of reservoir drilling rates.Fifth,based on the open-hole segmented accurate acid fracturing technology of highly-deviated and horizontal wells,the difficulty in the highly-heterogeneous reservoir stimulation by horizontal well drilling is solved by conducting the differentiated acid fracturing process of“one segment,one strategy”.Based on the application of these innovative development technologies in the Deng 4 Member gas reservoir in the marginal platform belt of the Anyue gas field,the annual natural gas production capacity and cumulative natural gas production by the end of December 2020 are 60×10^(8) m^(3) and 103×10^(8) m^(3),respectively.In this way,the Sinian Dengying Formation gas reservoir of the Anyue gas field,the economic benefit of which is close to the marginal benefit,becomes the main force of conventional natural gas production increase.展开更多
文摘平方公里阵列(Square Kilometer Array,SKA)射电望远镜的低频阵列SKA1-LOW将承担宇宙再电离(Epoch of Reionization,EoR)等关键科学研究任务.频率平均计算可以有效降低数据量、提高成像灵敏度,但所带来的“带宽效应”对SKA1-LOW成像的影响还缺少定量的分析和研究.采用仿真方法,对频率平均效应进行了深入研究.通过对SKA1-LOW进行全阵列仿真、频率平均和洁化处理,系统对比了平均多频道及单频道情况下的复原图,分析两者相减后的残差图.深入分析了频率平均对观测源强度的影响,得到峰值强度在不同成像权重时随平均频道数变化的定量结果,为SKA1-LOW实际观测中选择合适的频率平均频道数提供了参考依据,对于SKA1-LOW开展科学研究具有重要的价值.
基金Supported by the National Science and Technology Major Project of China(2016ZX05015)PetroChina Science and Technology Project(2021DJ1504).
文摘The reservoir space,types and distribution characteristics of karst carbonate gas reservoirs in the fourth member of Sinian Dengying Formation(Deng 4 Member)in central Sichuan Basin are analyzed based on the drilling,logging and seismic data.A development model of karst reservoirs is constructed to support the high-efficiency development of gas pools.The research shows that the reservoirs in Deng 4 Member have mainly small-scale karst vugs and fractures as storage space,and can be divided into three types,fracture-vug,pore-vug and pore types.The development patterns of the karst reservoirs are determined.On the plane,the karst layers increase from 65 m to 170 m in thickness from the karst platform to the karst slope,and the high-quality reservoirs increase from 25.0 m to 42.2 m in thickness;vertically,the reservoirs at the top of Deng 4 Member appear in multiple layers,and show along-bedding and along fracture dissolution characteristics.The reservoirs at the bottom are characterized by the dissolution parallel to the water level during the karstification period,and have 3-5 large-scale fracture-cave systems.Based on the reservoir development characteristics and the genetic mechanism,three types of reservoir development models of karst reservoir are established,i.e.,bed-dissolved body,fracture-dissolved body and paleohorizon-dissolved body.The construction of karst reservoir development models and seismic response characteristics of the three types of reservoirs can provide parameter for well placement and trajectory design,and substantially improve productivity and development indices of individual wells and gas reservoirs.The designed production capacity of the gas reservoir has enhanced from the initial 3.6 billion to 6 billion cubic meters,making the profit of the reservoir development increase noticeably.
基金Project supported by the National Science and Technology Major Project“Demonstration Project of Giant Carbonate Gas Field Development in Sichuan Basin”(No.2016ZX05052)the PetroChina Major Technology Special Project“Research and Application of Key Technology for Large-scale Efficient Development of the Fourth Member of Dengying Formation in Central Sichuan”(No.:2016E-0606).
文摘The Sinian Dengying Formation gas reservoir in the Anyue gas field of the Sichuan Basin is an ultra-deep ancient dolomite karst gas reservoir,whose development is of high difficulty,for the reservoir is thin and scattered with strong heterogeneity and is overall characterized by low porosity and low permeability.In order to provide support for the large-scale productivity construction of the gas reservoir of the fourth member of Dengying Formation(Deng 4 Member)in the marginal platform belt of the Anyue gas field,this paper carries out multi-discipline comprehensive researches on the technical bottlenecks based on the geological characteristics of the gas reservoir.In addition,the targeted key technologies for the efficient development of gas reservoirs were developed in the mode of“simultaneous research,application and improvement”.And the following research results are obtained.First,based on the modeling technology of fracturedevuggy dolomite karst reservoirs,accurate modeling of karst reservoirs is realized.Late actual drilling results show that the model's coincidence rate is increased from 63.0% to 90.7% and the“transparency”of gas reservoirs is achieved.Second,based on the reserve mobility evaluation technology of lowporosity and highly-heterogeneous karst reservoirs,the recovery factors of different reservoirs are determined.And consequently,the lower limit of well-controlled reserves and radius for the efficient development of different reservoirs are obtained and type Ⅰ and Ⅱ reservoirs are selected as the main development targets.Third,based on the development optimization design technology of highly-heterogeneous karst gas reservoirs,it is recommended to apply highly-deviated wells(the maximum deviation angle of 75°-84°)in the situations with multiple reservoirs crossed and superimposed.If type Ⅰ and Ⅱ reservoirs are developed intensively,it is recommended to adopt horizontal well drilling with a horizontal section of 800-1100 m.What's more,the reasonable well spacing in type Ⅰ and Ⅱ reservoirs shall be 1.6-3.3 km and 0.9-1.4 km,respectively.Fourth,based on the distinguished drilling technology of highly-deviated wells/horizontal wells in deep carbonate rocks,the fault complexity ratio is decreased from 20.7% to 4.9%,so safe and fast drilling and completion of highly-deviated wells/horizontal wells is realized and well control risks are diminished.What's more,the drilling rates of type Ⅰ and Ⅱ reservoirs are increased from 24.2% to 87.3%,indicating an effective improvement of reservoir drilling rates.Fifth,based on the open-hole segmented accurate acid fracturing technology of highly-deviated and horizontal wells,the difficulty in the highly-heterogeneous reservoir stimulation by horizontal well drilling is solved by conducting the differentiated acid fracturing process of“one segment,one strategy”.Based on the application of these innovative development technologies in the Deng 4 Member gas reservoir in the marginal platform belt of the Anyue gas field,the annual natural gas production capacity and cumulative natural gas production by the end of December 2020 are 60×10^(8) m^(3) and 103×10^(8) m^(3),respectively.In this way,the Sinian Dengying Formation gas reservoir of the Anyue gas field,the economic benefit of which is close to the marginal benefit,becomes the main force of conventional natural gas production increase.
