深层气井定产试采施工冻堵问题处理及预防方法  

Treatment and prevention of hydrate freezing in deep gas wells during production test

作　　者：李铁 Li Tie(Well Test & Production Test Company, PetroChina Daqing Oilfield Company,Daqing, Helongjiang 163412,China)

机构地区：[1]中国石油大庆油田有限责任公司试油试采分公司试油大队

出　　处：《天然气勘探与开发》2019年第2期123-128,共6页Natural Gas Exploration and Development

摘　　要：庆深气田深层气井试气施工中,平均每年都会出现10井次以上的因水合物冻堵而关井的现象,造成试气资料录取不准,还延长了施工进度,增加了施工成本和施工风险。为此,以多次发生水合物冻堵的深层气井——SS103H井为切入点,在地面试气流程中加入加热炉和保温管线,采用油嘴管汇、分离器二级节流降压,提高油嘴管汇下游与分离器之间的压力至10 MPa,在井口和油嘴管汇上游处注入乙二醇防冻堵剂,向除砂器砂筒内倒入乙二醇防冻堵剂至出气口位置,从而顺利完成了该井的试采施工。现场应用结果表明防止水合物冻堵的具体措施:①施工前做出冻堵预判,选择合理的工作制度及地面试气流程;②做好保温措施以及注入防冻堵剂的准备;③采用逐级降压法,并结合二级或三级节流降压法进行试气施工,从而保证试气施工的顺利进行。该施工措施为庆深气田的深入勘探、开发打下了良好的基础,为防止水合物冻堵提供了技术支撑。For some deep gas wells in Qingshen gasfield, during their well test, well shut in caused by hydrate freezing happened over 10 well times annually in average, which might result in inaccurate recording of well test data, delay a construction schedule, and increase construction costs and risks. SS103H well, a deep gas well which has suffered hydrate freezing for many times, was taken as example. Heaters and insulated pipelines were added into the process of ground well test. The two-stage throttling depressurization of choke manifold and separator was adopted to increase pressure difference between downstream of choke manifold and separator to 10 MPa. Glycol anti-freezing agent was injected at wellhead and manifold upstream. This agent was injected into sand cylinder of desander until it reached to gas exit. Thus, the production test of SS103H well was completed smoothly. Some measures against hydrate freezing are made, including,(1) to prejudge the freezing before construction, and to select rational working system and ground well test process;(2) to take some insulation measures and to make good preparation for injecting anti-freezing agent;and (3) to adopt one method of stepwise depressurization and another method of two-stage or three-stage throttling depressurization during well test to keep it smoothly. These construction measures lay the solid foundation for thorough exploration and development of Qingshen gasfield, and provide the technical support for preventing hydrate freezing.

关 键 词：庆深气田 深层气井 定产 试采 水合物 冻堵 预防 措施 

分 类 号：TE37[石油与天然气工程—油气田开发工程]