围岩—煤储层缝网改造增透抽采瓦斯理论与技术  

A theory and technical system of permeability enhancement to extract coal gas by fracture network stimulating in adjacent rocks and coal reservoirs

作　　者：马耕[1] 苏现波[2] 蔺海晓[2] 郭红玉[2] 陶云奇[1] 刘晓[2] 

机构地区：[1]河南煤业化工集团有限责任公司 [2]河南理工大学能源科学与技术学院

出　　处：《天然气工业》2014年第8期53-60,共8页Natural Gas Industry

基　　金：国家自然科学基金资助项目"煤层生物甲烷的形成机理研究"(编号:41002047;40972109)

摘　　要：现行的储层改造工艺仅适用于硬煤,对软煤则无能为力,这是造成我国煤层气产业化难以取得突破的主因这一,探索一种实现各类储层强化增透的普适性技术是当务之急。为此,采用理论分析与现场试验相结合的方法,系统分析了水力压裂过程中径向引张、周缘引张和剪切裂缝等多级、多类裂缝形成的力学机制,揭示了围岩—煤储层缝网改造的增透机理。结果表明:水平井分段多簇射孔压裂、水力喷射分段压裂、四变压裂以及一些辅助措施是实现缝网改造的有效技术途径,尤其是四变压裂使得煤层气垂直井和丛式井的缝网改造成为现实。结论认为:围岩抽采层缝网改造技术以钻井施工安全、可改造性强、抗应力敏感和速敏能力强、适合于任何煤体结构煤储层为特点,因而具有显著的优势;该技术除了在围岩水敏性极强、富水性强的条件下使用尚有局限外,具有广泛的适应性。煤层气地面开采和煤矿井下抽采成功的工业性试验表明,所构建的围岩—煤储层缝网改造理论和技术体系,将作为一种广普性的增透措施在我国煤层气井地联合抽采领域发挥作用。The existing reservoir stimulating technology is only applicable to hard coal but unsuitable for soft coal, which restricts the CBM industrialization in China. It is urgent to develop a universal stimulating technology which can increase the permeability in vari- ous coal reservoirs. Theoretical analysis and field tests were used to systematically analyze the mechanical mechanism of the forma- tion of radial tensile fractures, peripheral tensile fractures, shear fractures and other multistage various fractures in hydraulic fractu- ring and to work out the mechanism of permeability enhancement by fracture network stimulating in adiacent rocks and coal reser- voirs. It is shown that multiple perforation staged fracturing of horizontal wells, hydraulic-jet staged fracturing, quadruplex hydraulic fracturing and some auxiliary measures are effective technical approaches to achieving fracture network stimulating, especially quad- ruplex hydraulic fracturing that can stimulate the fracture network in vertical and cluster wells. The fracture network stimulating technology for adjacent rock mining layers has significant advantages, such as safe drilling operation, strong renovation, strong anti- stress sensitivity, and strong velocity sensitivity, so this technology is suitable for coal reservoirs with any coal structures. In addi- tion to adjacent rocks with strong water sensitivity and a high water yield, the technology is also strong in adaptability. Thus, a suc- cessful industrial test conducted on ground and under coal mines proves that the theory and technical system of fracture network stimulating in adjacent rocks and coal reservoirs will play a role as a widely applicable measure in the CBM development in China.

关 键 词：煤层瓦斯 顶底板 围岩抽采层 缝网改造 增透机理 四变压裂 技术 

分 类 号：TD712.6[矿业工程—矿井通风与安全]