缅甸D区块井壁稳定性周期浅析

缅甸D区块属于山前高陡构造,地质情况极为复杂。在已完钻井中遇到了严重漏失、井壁坍塌、地层高压且钻遇多套压力系统等问题,给钻井作业带来了很大的挑战。文章结合已钻井的具体情况,对采集到的岩屑、岩心进行了室内实验分析,并利用岩石力学相关理论,对泥页岩吸水量随时间变化以及岩石强度在钻井液浸泡下的变化规律进行了分析,建立了渗流压力和附加应力场模型,得出了井壁稳定性周期的估算值,为今后该地区钻井作业过程中优化钻井设计和安全钻井提供了理论依据。

ANALYSIS OF BOREHOLE COLLAPSE CYCLE ON MYANMAR BLOCK D

The high and steep structure of Myanmar block D has resulted in complex geological condition for drilling operation.Many downhole problems such as severe loss circulation,borehole collapse,high formation pressure and the existence of different pressure gradient formation in the same hole section were encountered while drilling which have brought great challenges for safe drilling in this block.The variation of shale water absorption with time and the alteration rule of rock strength due to soaking into drilling fluid are analyzed.Based on the data of completed wells and experiment results of cuttings and cores and related theory of rock mechanics,the model for seepage force and additional stress field around borehole is established.The borehole stability cycle has been estimated under the actual condition.The conclusions in this paper are very helpful for optimizing drilling program and safety drilling measures in this area.