气体钻井环空岩屑颗粒碰撞对井壁稳定性的影响  

Gas Drilling: How Collision of Cutting Particles in Annular Space Affect Wellbore Stability

作　　者：高如军[1] 何世明[1] 补成中[1] 何东升[1] 张荣志[2] 叶明泉[3] 章景城[3] 

机构地区：[1]西南石油大学 [2]吐哈油田工程技术研究院 [3]塔里木油田分公司

出　　处：《钻井液与完井液》2007年第B09期69-71,129,共3页Drilling Fluid & Completion Fluid

基　　金：国家自然科学基金项目(50674077);863项目(2006AA09Z312)资助

摘　　要：在气体钻井条件下,井壁失稳的可能性更大,其原因之一是由高速上返的气流携带的岩屑与井壁碰撞所引起的。在流体力学基础上,对气体钻井流体环空流动做了一定的简化,建立了气体钻井流体环空流动模型,推导出了固相颗粒在环空中的理论最大速度;建立了环空固相颗粒碰撞模型,得到了环空岩屑颗粒碰撞的最大剪切应力和最大静摩擦力;将由原地应力产生的应力与环空岩屑碰撞产生的最大剪切应力叠加而求得了井周应力,运用Mohr-Coulomb强度准则分析了气体钻井过程中井壁的稳定性。研究结果对选用气体钻井应用井段和预测井壁岩石的稳定性具有一定的指导意义。In gas drilling,much more attention should be paid to the wellbore stability issues,one reason is that the collision of the drilled cuttings entrained in the high velocity gas flow with the wall of the hole.A model for simulating the flow of gas in annular space was established by simplifying the flow behavior of gas in the annular space.Using the derived theoretical maximum flow velocity of cutting particles in the annular space,and the particle collision model,the maximum shear strength and maximum static friction of the particle collision were obtained.Superimposing the stresses generated by the in-situ stress and the obtained maximum shear strength gave the stresses in the formations around the wellbore.Wellbore stability was analyzed using Mohr-Coulomb strength criteria.The research results provide guidelines to the selection of a certain portion of a well in which gas drilling is feasible,and to the prediction of the formation rock stability.

关 键 词：气体钻井 流动模型 颗粒碰撞 井眼稳定 

分 类 号：TE242.7[石油与天然气工程—油气井工程] TE254.1