考虑天然裂缝的深煤层裂缝穿层扩展控因分析  

Analysis of controlling factors for the expansion of deep coal seam cracks through layers considering natural cracks

作　　者：吉俊杰 黄志强[1,2] 孔祥伟 Ji Junjie;Huang Zhiqiang;Kong Xiangwei(School of Petroleum Engineering,Changjiang University,Wuhan 430100,China;Hubei Provincial Key Laboratory of Oil and Gas Drilling Engineering,Wuhan 430100,China)

机构地区：[1]长江大学石油工程学院,湖北武汉430100 [2]油气钻采工程湖北省重点实验室,湖北武汉430100

出　　处：《能源与环保》2025年第3期108-114,122,共8页CHINA ENERGY AND ENVIRONMENTAL PROTECTION

基　　金：中海油“十四五”规划重大项目(CCL2022RCPS0471RSN,CCL2022RCPS0038ESN);国家自然科学基金项目(52374027)。

摘　　要：为研究深煤层条件下顶板压裂裂缝在煤岩界面处的穿层和扩展规律,考虑煤储层天然裂缝、煤岩界面粗糙度、界面抗剪切能力等参数,通过数值模拟和实例验证,分析水平主应力差、弹性模量、排量等参数,对顶板压裂裂缝穿层扩展的影响。结果表明,随水平主应力差增大,裂缝穿层扩展变得逐渐困难;随弹性模量差异增大,裂缝穿层扩展变得逐渐容易;随起裂位置距煤层顶面距离增大,裂缝穿层扩展的缝长总体呈现减小的趋势;随排量的增大,裂缝穿层扩展更加容易,但增加了界面失稳破坏的可能性,不利于裂缝的穿层。通过模拟发现,当顶板与煤层的弹性模量差异≤18 GPa、水平主应力差在3~7 MPa,是深煤层顶板压裂施工的最佳地层参数范围。通过实例验证发现,临兴L井在合适的地层参数范围内,调整起裂位置距离煤层顶面1.5 m、排量控制在16.5~18.0 m^(3)/min时,有较为优异的压裂效果;相较于浅煤层的顶板压裂,水平主应力差和弹性模量差异是影响深煤层顶板压裂能否开展的关键因素。研究成果可为涉及天然裂缝的深煤层顶板压裂提供理论参考意义。In order to study the penetration and expansion law of roof fracture cracks at the coal-rock interface under the condition of deep coal seams,the parameters such as horizontal principal stress difference,elastic modulus and displacement on the penetration and expansion of roof fracture cracks was analyzed through numerical simulation and example verification,taking into account the natural cracks in coal reservoirs,the roughness of the coal-rock interface,and the interface shear-resistant capacity.The results show that with the increase of horizontal principal stress difference,the crack extension through layers becomes difficult;with the increase of elastic modulus difference,the crack extension through layers becomes gradually easier;with the increase of the distance of crack initiation position from the top surface of the coal seam,the overall tendency of crack extension through layers shows a decrease in the length of the crack;with the increase of displacement,the crack extension through layers is easier,but it increases the possibility of the interface instability and failure,which is not conducive to the crack extension through layers.Through simulation,it is found that when the difference in elastic modulus between the roof and the coal seam is≤18 GPa,and the difference in horizontal principal stress is 3-7 MPa,it is the optimal range of stratigraphic parameter for the fracturing construction of the roof of the deep coal seam.Through example verification,it is found that Linxing L well has excellent fracturing effect when the fracture starting position is adjusted to be 1.5 m away from the top surface of the coal seam and the displacement is controlled to be 16.5-18.0 m^(3)/min within the range of suitable stratigraphic parameters.Compared with the roof fracture of shallow coal seams,the difference in horizontal principal stress and elastic modulus are the key factors affecting whether the roof fracture of deep coal seams can be carried out.The research results of this paper can provide theoretical refe

关 键 词：顶板压裂 深煤岩界面 裂缝穿层扩展 天然裂缝 数值模拟 

分 类 号：TE377[石油与天然气工程—油气田开发工程]