煤层气储层水力压裂裂缝扩展模型分析及应用  

Analysis and application of fracture propagated model by hydraulic fracturing in coal-bed methane reservoir

作　　者：许露露[1] 崔金榜[2,3] 黄赛鹏 汤继丹 蔡路[1] 喻鹏[2,3] 

机构地区：[1]中国地质大学(北京)能源学院,北京100083 [2]中国石油华北油田分公司,河北任丘062552 [3]中国石油天然气集团公司煤层气开采先导试验基地,河北任丘062552

出　　处：《煤炭学报》2014年第10期2068-2074,共7页Journal of China Coal Society

基　　金：大型油气田及煤层气开发重大专项资助项目(2011ZX05061);教育部新世纪优秀人才支持资助项目(NCET-11-0721);中央高校基本科研业务费资助项目(2652013026)

摘　　要：以往对于水力压裂裂缝扩展模型的研究,主要集中在砂泥岩储层,而对煤储层的研究较少。以沁水盆地安泽区块煤层气储层为例,建立了水力压裂裂缝扩展模型并对该模型的现场应用进行了研究。首先通过煤储层水力压裂裂缝形态的分析,选取相应的裂缝模型;然后运用滤失经典理论并结合煤储层应力敏感性特征,提出了动态滤失系数计算方法,进而建立了裂缝扩展数学模型并对影响缝长的主要因素进行了评价;最后,应用模型对煤层气井的裂缝几何参数进行计算,并与现场裂缝监测数据比较,提出了模型适用的地质条件。研究结果表明:安泽地区煤储层水力压裂以形成垂直缝为主;考虑煤储层应力敏感性后,研究区综合滤失系数从3.36 mm/min1/2增大到4.24 mm/min1/2,在影响缝长的诸多参数中,排量、滤失系数和压裂时间是最主要的3个因素;模型计算缝长和裂缝监测数据吻合较好,但模型应用也有一定的限制条件,适用于水力压裂不压开煤层顶底板,以及天然裂缝发育较少的煤储层。In developing the fracture propagation model of hydraulic fracturing, previous studies were mainly tocused on sandstone and mudstone reservoir and less on coal reservoir. Taking a coal-bed methane reservoir of Anze bh）ck in Qinshui basin as an example,this paper developed a fracture propagation model, and then applied the model on a site operation. Initially,this paper chose a suitable fracture propagation model on the basis of hydraulic fracture shape. Then, based on the classic filtration theory and the characteristic of stress sensitivity of coal reservoir, the paper pro- posed a computing method of comprehensive filtration coefficient, and then analyzed the factor effect on fracture length. Finally, the paper calculated fracture length and width by using the fracture model and analyzed the prerequi- site for fracture model. The results show that：the coal reservoir forms vertical fracture by hydraulic fracturing;when considering stress sensitivity, the value of comprehensive filtration coefficient increases from 3.36 mm/min^1/2 to 4. 24 mrn/min^1/2 ;the pumping displacement,filtration coefficient and fracturing time are three main factor effects on fractures＇ length. The fracture length from model calculation fits well with the fracture monitoring data only when the natural fracture is less developed and the fracture propagation is confined in coal seam.

关 键 词：煤层气储层 水力压裂 裂缝扩展模型 滤失系数 

分 类 号：P618.11[天文地球—矿床学]