煤储层破裂压力对压裂改造的影响与工程应用  

Influence of coal reservoir fracture pressure on fracturing reconstruction and its engineering application

作　　者：冯兴凯 FENG Xingkai(The Second Exploration Team of Shandong Coalfield Geologic Bureau,Jining 272000,China)

机构地区：[1]山东省煤田地质局第二勘探队,山东济宁272000

出　　处：《煤矿安全》2024年第3期84-90,共7页Safety in Coal Mines

摘　　要：我国煤储层渗透率普遍较低,低渗储层直接进行地面煤层气开发的效益较低,而水力压裂是增加煤储层渗透率和导流能力的有效手段。通过对沁水盆地PN-1井、PN-2井的测井参数进行分析,掌握煤储层的岩石力学特征,为煤储层水力压裂参数优化提供指导。结果表明:2口井的测井数据反演的煤层具有低泊松比、低杨氏模量、低强度、低破裂压力的特点;通过在前置液阶段控制施工排量及施工压力、提高阶段液量,可以有效避免压裂裂缝沿煤层顶底板之间的层间界面延伸及扩展至煤层顶底板;测井数据反演的PN-1井煤层破裂压力与实际压裂施工的破裂压力较接近,误差仅为3.01%,对压裂施工参数优化的指导意义较高;PN-2井煤层破裂压力略低于顶底板岩层的破裂压力,压裂初期的施工排量偏高,导致施工压力达到顶底板的破裂压力,压裂裂缝在顶底板之间延伸形成单一裂缝,改造效果及产气效果均较差。The permeability of coal reservoirs in China is generally low,and the benefit of direct development of surface coalbed methane in low permeability reservoirs is low,and hydraulic fracturing is an effective means to increase the permeability and conductivity of coal reservoirs.Based on the analysis of logging parameters of well PN-1 and well PN-2 in Qinshui Basin,the rock mechanics characteristics of coal reservoir are mastered,which provides guidance for the optimization of hydraulic fracturing parameters of coal reservoir.The results show that the coal seam derived from the logging data of the two wells has the characteristics of low Poisson’s ratio,low Young’s modulus,low strength and low rupture pressure.By controlling the construction displacement and pressure and increasing the liquid volume in the pre-liquid phase,the fracturing fracture can be effectively prevented from extending along the interlayer interface between the top and bottom of the coal seam and extending to the top and bottom of the coal seam.The fracture pressure of coal seam in well PN-1 obtained from logging data is close to the actual fracturing pressure,and the error is only 3.01%,which has a high guiding significance for the optimization of fracturing construction parameters.The fracturing pressure of the coal seam in well PN-2 is slightly lower than that of the top and bottom rock,and the construction displacement in the initial stage of fracturing is high,resulting in the construction pressure reaching the fracturing pressure of the top and bottom,and the fracturing fracture extends between the top and bottom to form a single fracture,resulting in poor transformation effect and gas production effect.

关 键 词：瓦斯抽采 煤储层 破裂压力 水力压裂 可压性 改造效果 

分 类 号：TD712[矿业工程—矿井通风与安全]