沁水盆地煤层气水平井压裂技术改进

Improvement technology of CBM horizontal well fracturing in Qinshui Basin

为改善柿庄区块水平井压裂排采效果较差的现状,从柿庄区块7口煤层气直井压裂微裂缝监测解释着手分析,认为导致排采效果不佳的重要因素是压裂改造实际作用在煤层的支撑剂仅有10%左右。为使压裂施工更多地作用在煤层,提出了人工诱导方法形成水平裂缝的新思路,即在煤层内利用高效压裂液携砂诱导形成水平裂缝。通过室内试验和裂缝形态机理研究,并对柿庄区块J水平井进行了现场试验,压裂施工设计排量为8.5~9.5 m3/min,入井液量约1 000 m3,砂比为9%,压裂成功率达到100%,达到设计要求。微地震监测结果表明：压裂裂缝形态复杂,水平分量体积百分数在80%以上,主要表现为水平裂缝特征,充分说明技术具有可行性。人工诱导裂缝技术可为水平井提高压后产量提供技术保障。

In order to improve the current situation of the horizontal well fracturing effect in Shizhuang Block of Qinshui Basin, Seven CBM vertical wells were taken as an example to analyze the result of fracturing micro crack monitoring, discovering the reason why the production effect was not ideal ： the actual effect of fracturing in the coal seam of proppant was only about 10%.To make the fracturing effect more effective for the coal seam, the artificial induction method to form horizontal crack of coal seam was put forward, that is, the horizontal crack was induced by the effective fracturing fluid and proppant in the coal seam. Depending on the indoor experiment and crack morphology mechanism research,and J horizontal well artificial induction test was carried out in Shizhuang Block, the fracturing discharge rate was 8.5 - 9.5 m3/min with about 1 000 m3 fluid volume. The proppant concentration was 9% and the success rate of fracturing was 100% which reached the design requirements. The micro seismic monitoring results showed that the fracturing fracture morphology was complex and horizontal component volume percentage was over 80% and the crack characteristics were mainly horizontal crack, convincing that this technology was feasible.The artificial induced fracture technology could provide technical support for increasing horizontal well production.