轻质油油井沥青质沉淀清除作业

Cleanup operation of asphaltene precipitation in light oil wells

董涛 王海涛 高巧娟

DONG Tao WANG Haitao GAO Qiaojuan

中石化国际石油勘探开发公司伊朗公司，北京　100029 北京石油机械厂，北京　100083

Iran Company, International Petroleum Exploration & Production Corporation, SINOPEC, Beijing 100029, China Beijing Petroleum Machinery Factory, Beijing 100083, China

两伊边界轻质油油田主力产层A 油组在生产过程中，沥青质在井筒析出、沉淀的现象很严重，是无水开采阶段影响油井生产时率的主要因素之一。A 油组异常高压，地层原油中高含硫化氢，所以整个作业过程，油管和油套环空之间不允许建立循环，这些都给井筒沥青质沉淀清除工作带来了很大困难。本次施工先采用泵车小排量控压、分段挤入、分段浸泡以及分段返排的工艺，挤入过程中井筒被沥青沉淀堵死，之后改用连续油管通洗井和泵车小排量控压挤入与浸泡相结合的工艺，顺利完成作业，使油井恢复正常生产。本次作业历时5 d，现场施工过程艰难复杂，通过作业认识到高效的沥青质沉淀溶剂、连续油管通洗、泵车控压控排量挤入、浸泡时间和浸泡深度几方面紧密配合是保证施工成功的关键。

During production of the major productive zone-Oil Reservoir A in light oil oilfield close to Iran and Iraq borders, asphaltene precipitation and settling in wellbore is a severe problems and is one of the factors which affect the production time efficiency of oil wells in water-free production period. The Oil Reservoir A has anomalously high pressure and formation crude oil contains large amount of hydrogen sulphide (H2S), so no circulation should be established between the tubing and casing annulus during the operation process. All these factors pose great difficulty for removing the asphaltene precipitation on wellbore. In this job, the pumping unit was firstly used to control the pressure with small displacement, squeeze in fluid in stages and soak in stages and flow back in stages. During squeezing, the wellbore was fully blocked by asphaltene precipitation. Then coiled tubing was used to drift and wash the well in conjunction with controlling the pressure by pumping unit with small displacement and soaking. The job was completed successfully and the oil well resumed normal production. This job lasted 5 days and experienced very difficult and complex times. From the job, it is learned that close combination of efficient asphaltene precipitation solvent, drifting by coiled tubing, squeezing by pumping unit with controlled pressure and displacement, soaking duration and soaking depth is the key to the success of the job.

10.13639/j.odpt.2015.05.028