The Longwangmiao Fm group gas reservoirs in the Moxi structure in central Sichuan Basin feature high temperature,high pressure and high H2S content.The thickness of such high permeable reservoirs with great homogeneit...The Longwangmiao Fm group gas reservoirs in the Moxi structure in central Sichuan Basin feature high temperature,high pressure and high H2S content.The thickness of such high permeable reservoirs with great homogeneity is a geologic basis for a high-productivity gas well,and good match of natural fractures and vugs is the key factor to high well productivity.Overbalance drilling is likely to cause the opening-up of natural fractures,which will lead to the leakage of drilling fluid and severe damage to the reservoir.Experimental evaluation results show that the damage rate of the drilling fluid to the rock sample is between 82.2%and 89.2%,which severely restricts the productivity of gas wells.Therefore,it is necessary to deepen the experimental evaluation technologies and methods to promote the design pertinence of technical parameters.The study shows:first,the optimized gelling acid and steering acid are effective in slowing down speed and removing blockage,forming acidizing wormholes and effectively eliminating the blockage effect caused by drilling liquid pollution;second,the self-developed fiber steering agent and soluble temporary blocking ball can divert the acid,increasing the processing pressure at the well bottom by 5-15 MPa,realizing the even stimulation of heterogeneous reservoirs;third,based on experimental evaluation such as the acid penetration and acid rock reaction,it is recommended that the pumping rate be 3.0-3.5 m^(3)/min in acidizing treatment and the acid intensity for blockage removal be 3.0-5.0 m^(3)/m;fourth,the established blockage removal and steering acidizing technology have been applied in more than 20 wells with a remarkable productivity-increase effect,which gives full play to the natural productivity of gas wells and decreases the acid application scale.All these technologies and measures effectively enhance the development quality and profit of the gas reservoir.展开更多
The main zone of production of Sinian gas reservoirs in the Sichuan Basin(China)is the Deng 4 member of the Gaoshiti–Moxi structure.In the Deng 4 member,the rock type is mostly dolomite,and the main types of storage ...The main zone of production of Sinian gas reservoirs in the Sichuan Basin(China)is the Deng 4 member of the Gaoshiti–Moxi structure.In the Deng 4 member,the rock type is mostly dolomite,and the main types of storage space are brecciated interporosity and large-scale interporosity characterized by low porosity and low permeability(average porosity:3.21%,average permeability:2.19 mD).In the Gaoshiti structure of the Deng 4 member gas reservoir,annual gas production of 60 billion cubic meters has been realized using differential segmented acid fracturing stimulation technology.However,with development of the Moxi structure,such technology is unable to adapt the reservoir because it requires continuous optimization according to reservoir characteristics.To provide effective support for optimization of reservoir stimulation technology,this study performed experiments using a large-scale true triaxialacid fracturing model.On the basis of the simulation of the reservoir reconstruction process,optimization of the process was investigated,an optimization scheme was proposed,and a field test was performed.The results,which indicated that gelling acid fracturing technology can effectively improve the stimulation effect of the Deng 4 member of the Moxi gas reservoir and substantially increase single-well production,could provide technical support for enhanced production of the Gaoshiti–Moxi gas reservoir.展开更多
基金Special and Significant Project of National Science and Technology:“Research on Development Techniques of Complex Carbonate Gas Reservoirs”(No.2011ZX05015-003-005).
文摘The Longwangmiao Fm group gas reservoirs in the Moxi structure in central Sichuan Basin feature high temperature,high pressure and high H2S content.The thickness of such high permeable reservoirs with great homogeneity is a geologic basis for a high-productivity gas well,and good match of natural fractures and vugs is the key factor to high well productivity.Overbalance drilling is likely to cause the opening-up of natural fractures,which will lead to the leakage of drilling fluid and severe damage to the reservoir.Experimental evaluation results show that the damage rate of the drilling fluid to the rock sample is between 82.2%and 89.2%,which severely restricts the productivity of gas wells.Therefore,it is necessary to deepen the experimental evaluation technologies and methods to promote the design pertinence of technical parameters.The study shows:first,the optimized gelling acid and steering acid are effective in slowing down speed and removing blockage,forming acidizing wormholes and effectively eliminating the blockage effect caused by drilling liquid pollution;second,the self-developed fiber steering agent and soluble temporary blocking ball can divert the acid,increasing the processing pressure at the well bottom by 5-15 MPa,realizing the even stimulation of heterogeneous reservoirs;third,based on experimental evaluation such as the acid penetration and acid rock reaction,it is recommended that the pumping rate be 3.0-3.5 m^(3)/min in acidizing treatment and the acid intensity for blockage removal be 3.0-5.0 m^(3)/m;fourth,the established blockage removal and steering acidizing technology have been applied in more than 20 wells with a remarkable productivity-increase effect,which gives full play to the natural productivity of gas wells and decreases the acid application scale.All these technologies and measures effectively enhance the development quality and profit of the gas reservoir.
文摘The main zone of production of Sinian gas reservoirs in the Sichuan Basin(China)is the Deng 4 member of the Gaoshiti–Moxi structure.In the Deng 4 member,the rock type is mostly dolomite,and the main types of storage space are brecciated interporosity and large-scale interporosity characterized by low porosity and low permeability(average porosity:3.21%,average permeability:2.19 mD).In the Gaoshiti structure of the Deng 4 member gas reservoir,annual gas production of 60 billion cubic meters has been realized using differential segmented acid fracturing stimulation technology.However,with development of the Moxi structure,such technology is unable to adapt the reservoir because it requires continuous optimization according to reservoir characteristics.To provide effective support for optimization of reservoir stimulation technology,this study performed experiments using a large-scale true triaxialacid fracturing model.On the basis of the simulation of the reservoir reconstruction process,optimization of the process was investigated,an optimization scheme was proposed,and a field test was performed.The results,which indicated that gelling acid fracturing technology can effectively improve the stimulation effect of the Deng 4 member of the Moxi gas reservoir and substantially increase single-well production,could provide technical support for enhanced production of the Gaoshiti–Moxi gas reservoir.
