气体钻井破岩过程动态仿真模拟  

DYNAMIC SIMULATION OF ROCK-BREAKING PROCESS DURING GAS DRILLING

作　　者：练章华[1] 林铁军[1] 孟英峰[1] 宋周成[1] 乐彬[1] 

机构地区：[1]"油气藏地质及开发工程"国家重点实验室.西南石油大学

出　　处：《天然气工业》2008年第6期88-89,共2页Natural Gas Industry

基　　金：国家高技术研究发展计划(863计划)“气体钻井技术与装备”(编号:2006AA06A103);国家自然科学基金项目(编号:50774063)的资助

摘　　要：应用弹塑性力学、岩石破碎力学建立了气体钻井破岩过程动态模拟的有限元模型,模型中地层岩石力学特性为各向异性材料模式。以岩石临界塑性应变为依据来判断岩石材料是否被切削或剥落,在动态仿真模拟过程中,将这些剥落的单元去掉,形成钻井井眼和新的井底表面。用所建立的模型,动态模拟、分析了PDC钻头钻井时,在各向异性地层和地层倾角的干扰下PDC钻头破岩过程的瞬时冲击接触压力、井底和井壁的应力分布。为气体钻井的推广应用以及高陡构造地层防斜打快提供了理论基础和依据。Based on plasto elasticity and rock fragment mechanics,a dynamic model of PDC bit contacting with bottom-hole rock was established.The anisotropic material is considered for the model.The critical plastic strain value of the rock is taken to judge whether the rock has been cut and flaked away or not.The dynamic simulation simulates that a new well-bore and new bottom-hole floor come into being after the rock is being cut and flaked away.By using this newly established model and the dynamic simulation,analysis is made to study the distribution of instantaneous impact pressure produced when the PDC bit cutting the rock and the stresses exerted both on hole bottom and the wellbore,in consideration of the interference of anisotropic formation and formation dipping.It will act as theoretical basis for both the promotion of gas drilling and the deviation control during fast drilling through high-dip formations.

关 键 词：气体钻井 PDC钻头 动态模拟 井斜 有限元法 

分 类 号：TE21[石油与天然气工程—油气井工程]