缅甸大段凝灰质泥岩地层井壁稳定性分析*

缅甸Y-1井位于缅甸中央盆地火山岛弧带上,由于地应力复杂和钻遇大段凝灰质泥岩层,钻井过程中井壁坍塌严重,返出大量掉块。为保护油气层,尽量降低钻井液密度,本文结合钻井出现的复杂问题,通过掉块力学实验分析和测井资料研究,建立了压裂预测模型,分析了缅甸Y-1井的井壁稳定性问题的原因,进而在预测钻井液安全密度窗口的基础上,提出了在大段凝灰质泥岩地层钻井的井壁稳定性合理化建议。

Analysis on wellbore stability in large section tuffaceous shale formation in Burma*

The well Y-1 locates in Burma central basin volcano island arc belt. The side-wall coring was well serious in drilling with returning large number rock fragments for the complex crustal stress and drilling large section tuffaceous shale formation. For oil and gas protection, reducing the density of drilling fluid as far as possible, the paper builds a fracture prediction model through experimental mechanical analysis and log data research by combining with the complex problem in drilling. The reason for wellbore stability of the well Y-1 in Burma is analyzed based on the above model, and some suggests on how to drill to contain the wellbore stability in large section tuffaceous shale formation are proposed based the predicting safe drilling fluid density window.