长宁区块页岩气井排液技术现状及攻关方向探讨

THE CURRENT SITUATION OF FLOWBACK TECHNOLOGY AND ITS FURTHER DEVELOPMENT RESEARCH FOR SHALE-GAS WELLS IN CHANGNING BLOCK

页岩气储层具有脆性高、孔隙度和渗透率极低、天然微裂缝发育等特点,须通过大规模水力压裂作业形成复杂裂缝网络来获得工业气流。排液作为压裂和后期生产"衔上接下"的关键一环,在页岩气开发中被高度重视。目前长宁大多数页岩气井采用经验方法或者借助邻井的返排数据指导控制排液,缺乏理论依据。文章针对长宁区块页岩气井返排关井时间、返排速率、返排率、返排液矿化度等,提出了从五个方面进行排液技术研究:压裂后关井时间对裂缝扩展、气井产量的影响;返排液矿化度和离子成分变化的特征及离子来源;页岩气井返排效果影响因素及压裂液去向问题;压裂液滞留于地层对页岩气储层伤害及返排率对气井产量的影响;返排控制参数对返排率及支撑剂回流的影响。

Shale gas reservoir has high brittleness,low porosity,permeability,and natural characteristics of micro fracture development. It must form complex fracture network to improve the single well production through large-scale hydraulic fracturing operation. Flowback as fracturing and later production ' bit on the take' a key ring,it is highly valued in the shale gas development. The flowback control for most shale gas well in changning block by empirical methods or with the aid of adjacent well data,lack of theoretical basis. Aimed at shut-in time,flowback rate,flowback rate,flowback fluid salinity,etc,puts forward the flowback technology research from five aspects: Shut-in time after fracturing effect on crack propagation and the gas well production; Change characteristics and the cause of flowback fluid salinity and ionic composition; Flowback effect factors and where fracturing fluid; Fracturing fluid in formation damage on the shale gas reservoir and the influence of flowback rate on gas well production; The influence of contral parameters on the flowback rate and proppant backflow.