煤层气井整体压裂及排采技术研究--以延川南煤层气田为例

Study on CBM Well Integral Fracturing and Drainage Technology--A Case Study of Yanchuannan CBM Field

为了促进煤储层改造效果,有效实现井间干扰,提升气井产气水平,通过整体压裂试验,在单井排采制度基础上,建立煤层气井整体排采制度,并进行排采参数定量化研究。结果表明:以储层压力(P_(c))、临界解吸压力(P_(j))和井间干扰压力(P_(r))为井底流压关键控制节点,将整体排采制度划分为5个阶段,分别是井底流压快速调整阶段、井底流压缓慢调整阶段、井底流压基本一致阶段、同步降压排采阶段和井间干扰阶段;其中,井底流压快速调整阶段日降流压小于0.08MPa,井底流压缓慢调整阶段小于0.02MPa,井底流压基本一致阶段小于0.01MPa,同步降压排采阶段和井间干扰阶段小于0.005MPa。经过现场试验和应用,整体压裂的两个平台15口煤层气井,通过整体排采降压,产气效果明显好于相邻平台气井。

To promote coal reservoir transform effect,realize well interference effectively and elevate CBM well production level,through integral fracturing test,on the basis of single well drainage system has established CBM well integral drainage system and carried out drainage parametric quantitative study.The result has shown that taking the reservoir pressure(P_(c)),critical desorption pressure(P_(j))and well interference pressure(P_(r))as bottom-hole flowing pressure key control nodes partitioned the integral drainage system into:bottom-hole flowing pressure fast adjustment,sluggish adjustment and basically agreed,along with synchronous depressurization drainage and well interference totally 5 stages.In which,during bottom-hole flowing pressure fast adjustment stage,daily flowing pressure reducing is less than 0.08MPa,during sluggish adjustment stage less than 0.02MPa,basically agreed stage less than 0.01MPa,synchronous depressurization drainage and well interference stages less than 0.005MPa.Through site test and practices,15 CBM wells of integral fracturing in two platforms after integral drainage depressurization,CBM production effects are better than neighboring platform CBM wells obviously.