缅甸Inyashe-2井井塌情况分析与原因探讨

缅甸C2区块地质条件复杂、井壁失稳严重，为了控制后续钻井的井壁失稳，对已经发生的井壁失稳原因进行深入分析与研究。缅甸C2区块Inyashe-2探井在?311.1 mm井段遭遇了较为严重的井壁坍塌，通过分析该井的测井数据、井径数据、地层岩性、压力剖面，评价钻井液性能，结合该井的坍塌情况及特点，探讨了其失稳原因，认为Inyashe-2井井壁失稳主要原因一是部分井段钻井液液柱压力低于地层坍塌压力；二是钻井液封堵性不足，致使钻井液进入裂隙发育的地层，从而引发岩石强度下降，坍塌压力增高，井壁失稳。

Collapse analysis and reasons investigate in Well Inyashe-2 Myanmar

Due to complex geological conditions, severe borehole instability in Block C2 Myanmar, reasons to borehole instability need be analyzed and investigated to control subsequent borehole wall instability in drilling. The exploratory well Inyashe-2 in Block C2 Myanmar encountered serious borehole collapse in ?311.1 mm hole section. The characteristics of well collapse and its instability reasons were investigated by analyzing and studying on logging data, caliper data, formation lithology, pressure traverse and drilling fluid performance. The reasons to borehole instability are thought to be the follows: first, the liquid head of drilling fluid in several well sections are lower than formation collapse pressure. Second, the sealing property of drilling fluid is not enough to prevent drilling fluid seep into the fracture formation, which results that rock strength decreases, collapse pressure increases, and borehole instability occurs.