低压气藏地层压力预测与校正

PREDICTION AND CORRECTION OF LOW PRESSURE GAS RESERVOIR PRESSURE IN ORDOS BASIN

准确地计算地层三压力是实现安全快速钻井的必要条件,是确定合理的钻井液密度和进行井身结构设计等工程应用的基础。以鄂尔多斯盆地低压气藏为研究对象,分析低压气藏的形成机理,对井壁垮塌处的声波时差和密度测井曲线进行大井眼校正,建立并改进地层三压力计算模型,使之适用于鄂尔多斯盆地低压气藏,对盆地内多口气井地层三压力进行预测,同时结合实测地层三压力构建地层三压力剖面,并确定钻井液密度范围,有效地避免和减少钻进过程中复杂情况的发生。

It is necessary to calculate three- pressure of the formation accurately,which is the base of defining the drilling mud density and designing the well structure. Taking the low- pressure gas reservoir in Ordos Basin as the study object,through analyzing the formation mechanism of the low- pressure gas reservoir and correcting the curves AC and DEN in the zone of hole collapse,the three pressure calculation model was established and improved to fit for the low- pressure gas reservoir in Ordos Basin. The three- pressure of some wells in the Basin were predicted and the three- pressure profile was built by using the three pressure calculation model to determine the drilling mud density range,which could effectively avoid and decrease the complex case in the dirlling process.