摘要
煤岩强度低、节理发育的特性使煤岩坍塌与泥页岩坍塌在机理上有本质的区别。研究发现,当节理渗流压力小于某一定值时,煤岩节理最大位移、剪切位移呈线性变化;当节理渗流压力大于该定值时,节理位移呈级数增加。针对这一现象,应用流固耦合计算比较渗流和非渗流状态下不同钻井液密度下的煤岩节理位移,确定煤层防塌的合理钻井液密度,为煤层井壁稳定提供理论指导。
The collapse mechanism of coal rocks was essentially different from that of shales due to its well developed joints and low strength.It was found out that the maximum joint displacement and shear displacement were changed linearly when fluid pressure was less than a certain value,but they increased by orders of magnitude when the fluid pressure was higher than the value.The different joint displacements under different drilling fluid densities as well as seepage and non-seepage conditions are analyzed by using hydraulic-solid coupling.A reasonable drilling fluid density is determined for preventing collapse of coal seam,it provides a valuable guidance for stabilizing borehole in coal seam.
出处
《石油天然气学报》
CAS
CSCD
北大核心
2011年第5期134-136,339,共3页
Journal of Oil and Gas Technology
关键词
井壁稳定
数值模拟
流固耦合
煤层
borehole stability
numerical simulation
hydraulic-solid coupling
coal seam
