高危井取换套工艺技术研究

Technology of Casing Replacement/Retrieval in High-risk Wells

通过对大庆油田高危区块、异常高压油气水层以及浅气层的分布情况进行识别和划分,依据绘制的高危复杂区块图版,对位于浅气和异常高压区的取套施工井进行地质风险评估和评价。对高危区域施工的取套井采用射孔泄压、管内封堵、带原井套管补打表层后安装井控装置等技术措施进行预防喷处理,确保高危区取套施工的安全。考虑在高危区块进行取套施工存在巨大的安全风险,配套了相应的防喷抢险技术,包括井喷失控抢险技术、清障灭火抢险技术、井控拆除重建抢险技术和带压施工抢险技术等。应用高危井取换套工艺技术对施工的208口管外作业井进行了设计优化与施工指导,其中补打表层34口,无表层井免打表层比率77.5%,高危浅气井射孔封堵25口,井喷抢险井2口,共创造直接经济效益5000多万元。该技术在很大程度上解决了高危区套损井难以及时修复的问题。

Geologic risk of operating wells with casing retrieval at the areas of shallow gas and abnormal pressure is evaluated according to the high-risk complex block chart after the distribution of the high-risk blocks ,abnormal pressure reservoirs and shallow gas reservoirs is recognized and classified in Daqing oil- field.Pre-blowout prevention treatment is made for the casing retrieval wells in high-risk area through the technology of decompression by perforation,internal plugging and install of well control equipment after patching surface casing with the original well casing so as to ensure the operation safe in the high-risk area.Considering great safe risk of it, corresponding blowout emergency technology is set including emergen- cy technology for going wild ,obstacle removing and fire extinguishing technology ,well control removal and rebuilt technology and operation under pressure.Casing replacement/retrieval technology in the high-risk wells is applied to design optimization and operation guide for the operating 208 external wells in opera- tion.Among them there are 77.5% of no surface casing wells ,25 wells plugging by perforation in high- risk gas shallow reservoirs and 2 blowout emergency wells.It created direct economic benefit more than 50000 thousand Yuan.This technology solves the problem of being hard to repair on time for the casing damaging wells in the high-risk area mostly.