复杂井筒条件下的有机质测井计算方法优选

Optimization on the Logging Calculation Method of Organic Carbon Under Complex Wellbore Conditions

为了解决复杂井筒条件下有机质含量的计算问题,以永川地区龙马溪组深层页岩气储层为例,对不同井型条件下的测井资料进行有机质含量计算方法探讨。直井(取心井)中,由于获取测井资料丰富,分别采用体积模型法、ΔlogR法、体积密度法、自然伽马能谱法和多元拟合法对有机质含量大小计算;然后将计算结果与岩心数据进行误差分析,结果表明,工区内直井中多元拟合法、密度法为最佳计算模型。水平井中,受资料采集限制,提出运用伽马能谱叠合区域差值法与体积密度法相结合的方法,同时考虑轨迹的空间位置进行计算,该方法有效地解决了水平井有机质含量计算难题。本次研究对于不同井筒条件下的有机质计算模型作了较全面探讨与研究,值得四川及其他页岩气工区储层有机质含量计算参考与借鉴。

In order to solve the calculation problem of organic matter content in complex wellbore conditions,taking the deep shale gas reservoir of Longmaxi formation in the Yongchuan area as an example,the organic matter content calculation method of logging data under different well type conditions was discussed.Due to the abundant logging data obtained in vertical wells(coring wells),the volume model method,ΔlogR method,bulk density method,natural gamma spectroscopy method and multivariate fitting method were used to calculate the organic matter content;then,the error analysis was carried out between the calculation results and the core data.The results show that the multivariate fitting method and density method in vertical wells in the work area were determined as the best calculation models.In horizontal wells,limited by data acquisition,a method combining gamma spectrum superposition regional difference method with volume density method was proposed to effectively solve the problem of calculating organic matter content in horizontal wells by considering the trajectory's spatial position at the same time.This study has made a comprehensive discussion and research on the calculation model of organic matter under different wellbore conditions,which is worthy of reference for the calculation of organic matter content in reservoirs in Sichuan and other shale gas work areas.