延川南深部煤层气富集高产关键因素

Key Factors for Enrichment and High Production of Deep Coalbed Methane in Southern Yanchuan

通过梳理气田沉积环境、煤岩煤相、构造断层、储层物性等资料,总结气田深部煤层气储层主要有以下特征:(1)高含气量,一般大于12m^(3)/t;(2)高储层压力,一般大于6MPa;高地应力,破裂压力一般大于35MPa,停泵压力一般大于25MPa;低渗透率,一般低于0.3md;(3)高矿化度,一般大于5000mg/L。远离逆断层、高含气量、高储层压力、滞流水环境是延川南深部煤层气富集成藏的地质基础。多造缝、造长缝、远支撑的压裂改造思路,大排量压裂工艺,低密度自悬浮支撑剂是深部煤层气高产的关键技术。

By combing the data of the gas field sedimentary environment,coal facies,structural faults,and reservoir physical properties,it is concluded that the deep coalbed methane reservoir of the gas field mainly has the following characteristics:(1)high gas content,generally more than 12 m^(3)/t;(2)high reservoir pressure,generally more than 6 MPa,high in-situ stress,with fracture pressure generally exceeding 35 MPa and pump stop pressure exceeding 25 MPa,and low permeability,generally lower than 0.3 md;and(3)high salinity,generally more than 5000 mg/L.Being far away from reverse faults,high gas content,high reservoir pressure and stagnant water environment are the geological basis of deep coalbed methane accumulation in Southern Yanchuan.The key technologies for high production of deep coalbed methane include the fracturing reconstruction of multiple fractures,long fractures and remote support,the large displacement fracturing process,and the low-density self-suspension proppant.