沁水煤层气田郑庄区块二次压裂增产技术研究

Study on production increased technology with secondary hydraulic fracturing in Zhengzhuang Block of Qinshui Coalbed Methane Field

郑庄区块投入开发后存在部分低产井,主因是首次压裂工艺技术不适应低渗透、复杂高阶煤储层特性所致,为了提高该区块开发效果,研究了与该区块煤储层特性相适应的二次压裂增产技术。通过开展煤储层特性判别、二次压裂增产机理研究、改变压裂施工思路等工作,建立了适应不同煤储层特性的4种增产技术,并进行了80口井的现场应用。应用结果表明:低渗透煤层、构造软煤、大裂隙煤层实施二次压裂增产技术后,形成了新的人工裂缝或人工缝网,煤储层渗透率得到改善,能够提高低产井产气量,单井平均日增气650 m^3/d以上,该技术解决了郑庄区块低产井问题,对同类型煤层气田提高开发效果提供了参考。

There was some low production wells existed in Zhengzhuang Block after the development and the major causes were the first hydraulic fracturing technique and technology not suitable to the low permeability and high complicated high ranking coal reservoir features.In order to improve the development effect of the block,the secondary fracturing and production increased technology suitable to the coal reservoir features of the block was studied.With the distinguishment of the coal reservoir features,study on the secondary hydraulic fracturing and production increased mechanism,idea to change the fracturing construction and other work,four production increased technologies suitable to different coal reservoir features were established and were applied to the sites of 80 wells.The application results showed that after the secondary hydraulic fracturing and production increased technology conducted,new artificial cracks or artificial cracks network were formed in the low permeability seam,structure soft coal and high cracking seam. The permeability rate of the coal reservoir was improved and the gas production of the low gas production well could be improved. An average daily production of a single well had improved over650 m^3/d.The technology applied solved the low production well in Zhengzhuang Block and could improve the development effect of the similar type coalbed methane field.