摘要
Abstract
Depleted carbonate gas fields in the Sichuan Basin are the"ballast stone"of natural gas development in the Sichuan-Chongqing area.After more than 70 years of exploration and development,it has entered the middle and late stages of natural gas development.In this type of gas fields,there are a large number of scattered small rolling extension traps,low-grade natural gas reserves account for a high proportion with a low production degree and high measure difficulty,and surface gathering system has low newness,multiple gas sources,and various flow directions.As a result,"three difficulties"occur in the reserves and production increase of rolling extension,the recovery and production enhancement of inefficient gas reservoirs,and the efficiency improvement and production maintenance of gatheringe system,seriously restricting its long-term stable production of natural gas.To deal with these three core difficulties,this paper innovates the key technologies for long-term stable natural gas production of depleted gas fields through multi-disciplinary joint research of geology,engineering and information.The following results are obtained.First,the development mechanisms and control factors of gentle-slope bioherms are clarified,small bioherms smaller than 1 km2 can be characterized precisely,and the technologies for identification and fine characterization of deep hidden complex traps are developed,which can effectively identify small bioherms of 0.5 km2,with the accuracy rate rising from 55％to more than 90％.Second,the difficulties in the benefit production of remaining low-permeability reserves in depleted gas fields,water intrusion affecting the distribution of remaining gas,and efficient unsealing are addressed,and the technologies for the efficient production of low-permeability reserves and intelligent water control of gas reservoirs with edge/bottom water are developed,which increase the natural gas production of measure wells in low-permeability reservoirs by 3 to 5 times and the water control efficiency by 32％.Third,the difficulties in the optimization,control and efficiency improvement of the complex gathering system with three lows and three highs in depleted gas fields are addressed,the intelligent control technologies for data quality and stable operation of key equipment are developed,and the multi-dimensional intelligent optimization and allocation technologies for pipeline networks are formed,which increase the fault handling efficiency by 87.5％and the gas well production capacity utilization rate from 91％to 99％.In conclusion,the formation of the key technologies for long-term stable natural gas production provides a powerful support for the"reserves and production increase,recovery and production enhancement,and efficiency improvement and production maintenance"of the depleted carbonate gas fields in the Sichuan Basin.As a result,the economic benefits of these gas fields are remarkable.These technologies can provide useful reference for similar gas reservoirs at home and abroad.关键词
四川盆地/碳酸盐岩老气田/压舱石/开发中后期/长期稳产Key words
Sichuan Basin/Depleted carbonate gas field/Ballast stone/Middle and late stages of development/Long-term stable production分类
能源科技
