肯基亚克盐下石炭系高压油气藏防气窜尾管回接固井技术

Cementing Liners Techniques for Preventing Gas Channeling Used in High Pressure Carbonate Reservoirs in Kenya

石炭系碳酸盐岩储层是肯基亚克盐下油田的主力开发层,由于该储层地层压力高,安全密度窗口窄,存在溢漏同层,钻井液和水泥浆之间的密度差小,封固段长,循环压耗高,水泥浆失重严重,环形间隙小,井眼不规则,套管居中度差,造成固井后水泥胶结质量差,易发生环空气窜。为提高水泥胶结质量,该油田采用了防气窜尾管回接固井技术,并采取了一系列配套技术措施。10口井的现场应用表明,防气窜尾管回接固井技术提高了固井质量,解决了环空气窜问题。介绍了该油田防气窜尾管回接固井技术方案、技术措施,并以两口井为例介绍了该油田直井和大斜度井防气窜尾管回接固井的施工程序。

Carbonate reservoirs are the main pay zones of the Yanxia block in Kenya. However, the cement bonding strength is poor and gas channeling is prone to happen due to high formation pressure, narrow mud density window, circulating loss and kicking occurring at the same formations, small differences between drilling fluid density and cement slurry, long cementing hole section, high pressure loss, serious cement slurry weigh loss, narrow annulus, abnormal wellbore, bad casing string centralization. In order to improve cementing bonding strength, liner cementing technique along with other supporting measures was used to prevent gas channeling in this block. Field applications of this technique in 10 wells show that it improved cementing quality and prevented gas channeling. The technical process, technical measures of liner cementing technique were introduced. The application of this technique in two wells was used to introduce application procedure in vertical and high angle well.