延长气田井壁失稳机理研究

通过对延长气田地层岩心进行矿物组份和理化性能以及声波时差、密度、电阻率等测井数据分析得出,延长气田地层属于属硬脆性泥页岩地层,内部微裂缝比较发育,结合安全钻井液密度窗口计算结果得出,适当的提高钻井液的密度和封堵性,可减缓了钻井液沿微裂缝向地层的侵入,钻井液液柱压力可以长时间的保持对井壁的有效支撑,防止井壁坍塌。

Mechanism of Borehole Instability in Yanchang Gas Field

Through analysis of mineralogical composition, physical and chemical properties and interval travel time, density, resistibility logging data, it＇s pointed out that Yanchang field layer pertains to friable hard formation; The resident microcracks developed. Combined with the calculation result of the safe drilling fluid density window, it＇s pointed out that to suitably increase density and sealing ability of the drilling fluid can reduce the drilling fluid invasion to the formation along the micro fractures; the fluid column pressure can maintain effective support for the wall in a long time to prevent borehole collapse.