气测录井参数校正方法在非平衡钻井条件下的应用

Application of Correction Methods of Gas-Logging Parameters in Underbalanced Drilling

摘要: 平衡钻井条件下，气测录井参数可以进行对比和更有效地反映地层含油气情况，而非平衡钻井由于地层压力与钻井液液柱压力之间的压差原因，对气测录井参数造成直接影响。针对英台断陷非平衡钻井对气测录井参数的影响，通过对不同天然气产能条件下钻井压差与气测录井参数关系的分析，探讨了气测录井全烃体积分数及甲烷体积分数的校正方法，提出了指数确定、系数变化的压差回归校正法。该方法经英台断陷实际应用证明效果较好，对非平衡钻井条件下气测录井参数的标准化校正具有一定的指导意义。

Abstract: Under the condition of balanced drilling, the parameters of gas logging could be compared to better reveal the oil and gas conditions in the formation. In contrast, in underbalanced drilling, the parameters of gas logging were subjected to direct impact of pressure difference between formation pressure and drilling liquid column pressure. In this study, in view of the influence of underbalanced drilling on gas logging parameters in Yingtai Fault Depression, based on the analysis of the relationship between drilling pressure difference and gas logging parameters under different natural gas productivity conditions, differential pressure regression correction method with fixed index and variable coefficient is proposed for the volume fraction correction of total hydrocarbon and methane in gas logging. The method is proved effective through application in the Yingtai Fault Depression, which can guide the standardization correction of gas logging parameters in underbalanced drilling.