深水井筒海水聚合物钻井液水合物生成抑制与堵塞物处理方法  

Study on Methods of Gas Hydrate Inhibition and Blockage Treatment Using Seawater Polymer Muds in Deepwater Well Drilling

作　　者：吴艳辉 代锐 张磊 朱志潜 高禹 刘楷 徐鹏[2] 张雨 WU Yanhui;DAI Rui;ZHANG Lei;ZHU Zhiqian;GAO Yu;LIU Kai;XU Peng;ZHANG Yu(Engineering Technology Operation Center of CNOOC(China)Co.,Ltd.Hainan Branch,Haikou,Hainan 570100;College of Petroleum Engineering,Yangtze University,Wuhan,Hubei 430100)

机构地区：[1]中海石油(中国)有限公司海南分公司工程技术作业中心,海口570100 [2]长江大学石油工程学院,武汉430100

出　　处：《钻井液与完井液》2023年第4期415-422,共8页Drilling Fluid & Completion Fluid

基　　金：中海油重大科技专项“南海西部油田上产2000万方钻完井关键技术研究”(CNOOC-KJ 135ZDXM38ZJ05ZJ)。

摘　　要：在南海西部深水钻井过程中对于水合物的防治过于保守,使用的水合物抑制钻井液——HEM钻井液成本高,钻速低。为了降低钻井液成本,缩短钻井周期,针对深水钻井过程中低成本聚合物钻井液下水合物生成堵塞风险与处理方法问题,结合南海莺琼盆地BD区块钻井情况,对聚合物钻井液下不同气体组分的水合物生成相平衡曲线,不同工况下水合物生成区域,井筒水合物堵塞处理等开展了研究,得到不同工况下井筒水合物生成风险区域,优选了动力学抑制剂聚M-乙烯基己内酰胺作为水合物生成抑制剂,热力学抑制剂乙二醇作为水合物堵塞解堵剂,并在室内设计形成10种新型动力学抑制剂,其中动力学抑制剂DS-A3对水合物的生成有良好的抑制效果。实验研究以及BD某井现场应用表明:①在正常钻井循环、压井、关井工况下没有水合物生成区域,不会有水合物生成堵塞风险;②综合考虑抑制效果与成本,0.8%聚M-乙烯基己内酰胺对井筒水合物的抑制效果最好,45%的乙二醇对于解除井筒水合物堵塞风险效果最好;③在没有特殊复杂井下工况情况下,只要停钻时间不超过15 h,可以直接使用聚合物钻井液进行深水钻井,平均单井钻井液成本下降50%~70%,创造良好的经济效益。The methods of preventing and curing gas hydrate in deepwater drilling are too preservative.In the west of the South China Sea,the gas hydrate inhibitive drilling fluid HEM used in the deepwater drilling is quite expensive and the penetration rate is low.To reduce the mud cost and shorten the drilling time,several issues were studied,including the phase equilibrium curves of hydrate generation with different gas components,the regions for gas hydrate generation under different operating conditions,and the methods of dealing with borehole blockage by the gas hydrates.All these studies were conducted with the low cost polymer drilling fluids used in the deepwater drilling in the BD block in the Yinggehai basin(South China Sea).Potential regions for the generation of gas hydrates under different operating conditions were obtained.Based on these studies,poly(M-vinyl caprolactam)was selected as the kinetic gas hydrate inhibitor to inhibit the generation of gas hydrates glycol selected as the thermodynamic inhibitor to remove blockage in a wellbore by gas hydrates.Ten new kinetic inhibitors were designed in laboratory study,of which the DS-A3 inhibitor has good inhibitive capacity for gas hydrate generation.Laboratory study and field(block BD)application showed that:(1)in operating conditions such as normal drilling,circulation and well shut-in,no gas hydrate generation region exists,as such,there is no risks of wellbore blockage.(2)Considering the inhibitive effect and cost together,0.8%poly(M-vinyl caprolactam)has the best inhibitive effect for gas hydrate generation,and 45%glycol has the best effect for removing blockage of a wellbore by gas hydrate.(3)When there are no complex downhole operating conditions,if the rig down time does not exceed 15 hours,polymer drilling fluids can be directly used in deepwater drilling.In this way the drilling fluid cost for a single well can be reduced by 50%-70%,a good economic benefit.

关 键 词：深水钻井 聚合物钻井液 天然气水合物 生成堵塞 抑制剂 处理方法 

分 类 号：TE254.3[石油与天然气工程—油气井工程]