摘要
分段压裂水平井在国内的应用愈来愈广泛,但对其渗流机理及渗流特征的认识还不够明确,由于页岩气井特殊的生产方式,对其试井分析的研究基本上还处于空白状态。为此,首先研究了水平井分段压裂产生的裂缝形态,进而系统分析了分段压裂水平井在开发过程中的主要渗流特征及其在双对数曲线上的特征表现,考虑页岩储层的特殊性,给出了页岩气井生命期内通常表现出的渗流形态;结合中国第一口页岩气分段压裂水平井——W201-H1井的压力恢复测试数据,分析了该井在压力恢复双对数图上表现出的渗流特征,明确了该井在测试期表现出的径向流应属早期径向流,并验证了该井在未来1年内的生产均处于复合线性流阶段;通过前后3次压力恢复试井曲线的对比分析,指出要展现页岩气分段压裂水平井完整的渗流流态及其演化过程,获取准确的储层与裂缝参数,需要较长的关井时间,确保压力计尽量靠近水平段位置,并选择合适的关井点以最大限度地降低井储和井筒积液的影响。
Multi-stage fracking has been more and more widely applied to horizontal wells in China. However, its seepage behavior and characteristics have not yet thoroughly understood, and well test analysis has been seldom made for shale gas wells due to their unique production mode. In view of this, we firstly studied the geometry of fractures generated in multi-stage fracking for a horizon- tal wells then, systematically analyzed the main seepage features of the multi-stage fractured horizontal well during fracture treatment and the characteristics on log-log plot~ finally, derived the common seepage form within the life cycle of the well considering the particularity of a shale gas reservoir. Specifically, well W201-H1, the first shale gas horizontal well under multi-stage fracking in China, was taken as a case study. Based on its pressure buildup test data, we analyzed its seepage characteristics with pressure build- up log-log plot. According to the analysis, we found out that the radial flow in the test is at its early stage, and validated that the flow would be of a combined linear type in the production of the flowing one year. By comparing and analyzing the data in 3 times of pressure buildup tests, we discovered that in order to reveal the complete seepage flow state and evolution of shale gas horizontal wells under multi-stage fracking, and to obtain accurate reservoir and fracture parameters, it is necessary to ensure a relatively long shut-in period, to make the pressure gauge as close as possible to the horizontal interval, to adopt appropriate shut-in place, and there by, to minimize the impacts of well store and shaft liquid loading. The research achievements are instructive to shale gas development. Keywords..
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2013年第12期77-81,共5页
Natural Gas Industry
基金
国家科技重大专项"南方海相页岩气开采试验"(编号:2012ZX05018-006)
关键词
页岩气藏
水平井
分段压裂
渗流特征
试井
分析
四川盆地
shale gas reservoir, horizontal well, multi-stage fracking, seepage characteristics, well test, analysis, Sichuan Basin
