临河坳陷光明构造地层压力随钻监测技术研究

Study on monitoring technique of formation pressure while drilling in Guangming structure,Linhe Depression

河套盆地临河坳陷光明构造发育多套地层压力系统,受地质和工程等因素影响随钻地层压力监测结果精度低,井漏、坍塌、遇阻等事故频出,钻井提速困难。为此,提出应用测井、录井资料修正dc指数,结合区块地质条件,在一趟钻前提下分段建立正常压实趋势线,完善dc指数法地层压力随钻监测模型及方法。结果表明,应用上述方法监测的地层压力值与测井曲线预测地层压力值、钻井液密度及实际工况结果对比吻合率较高,可有效指导临河坳陷重点探井的地层压力监测工作。该方法对其他区块地层压力监测工作具有较好的借鉴意义。

The Guangming structure in Linhe Depression of Hetao Basin has developed multiple sets of formation pressure systems.Due to the influence of geology,engineering and other factors,the accuracy of formation pressure monitoring while drilling is low,the accidents,namely,lost circulation,caving,drill pipe blocking,etc.,occur frequently,making it difficult to improve drilling speed.Therefore,it is proposed to apply well logging and mud logging data to modify the dc index.Combined with the geologic conditions of the block,a trend line of dc index is established in sections under the premise of single trip drilling,and the model and method of dc index pressure monitoring while drilling are improved.The results show that the formation pressure monitored by the above method has a high coincidence rate with the predicted formation pressure from well log,drilling fluid density and actual working conditions,and can effectively guide the formation pressure monitoring work of key exploration wells in Linhe Depression.This method has a good reference significance for the formation pressure monitoring work in other blocks.