土库曼斯坦酸性气田恢复产能工程关键技术

土库曼斯坦Sa气田是一个高含H2S与CO2的底水块状碳酸盐岩气田，恢复利用老井产能是第一期产能建设目标的重要保证。该气藏老井封存时间长达13 ａ，修井采气面临井筒腐蚀评价、重新完井、腐蚀与防治、水合物预测等难题，存在较大的技术难度和安全风险。在对33口老井的采气工程进行了分析和评估的基础上，采用MIT/MTT井筒腐蚀评价和生产系统节点分析等方法，针对气田的储层特点和修井采气工程技术的难点，形成了高含硫气田恢复产能工程关键技术，主要包括老井修复与测试配套技术、生产系统优化技术、H2S与CO2的腐蚀与防治技术以及酸性气田高效酸化解堵技术。在已修复的9口井中恢复年产能12×１０８ｍ３，修复26口井预计恢复年产能（25~30）×１０８ｍ３，26口老井修复利用至少可节约钻井直接投资 8 000万美元以上。

Key technologies of restoring the productivity of sour gas fields in Turkmenistan

The gas field Sa in Turkmenistan belongs to a kind of bottom water block carbonate gas field with high H2S and CO2. To restore and utilize the productivity of old wells is an important guarantee for the target of the first term productivity construction in the CNPC's project of Turkmenistan. Since the old wells in this gas reservoir were shut in almost 13 years ago, either the workover or the gas production has faced all kinds of technical difficulties and safety risks in terms of  wellbore corrosion evaluation, recompletion, corrosion and prevention, and hydrate prediction and control, etc. Based on the analysis of and the evaluation on these 33 old wells, this paper adopted many methods such as MIT/MTT wellbore corrosion evaluation and node analysis of production system to develop a series of key technologies restoring the productivity of high sour gas fields, which mainly include the matching technique of well workover and testing, the optimizing technology of gas production system, the H2S and CO2 corrosion prevention technology, and the breakdown formation technology of sour gas fields by acidification with high efficiency. The annual production of the restored 9 wells is up to 12×108 m3, and the annual production of the restored 26 wells is predicted to be 25 30×108 m3, which at least saves above 80 million US dollars of direct drilling investment.