加拿大巴肯组“致密油”测井解释方法

"Tight-oil" Well Logging Interpretation Method of Bakken Formation in Canada

致密油属于典型的非常规油，通常指赋存于烃源岩内部碳酸盐、碎屑岩夹层或者紧邻烃源岩的致密砂岩储层中的石油。加拿大巴肯组为目前北美地区致密油主要的储层，该储层具有超低的孔隙度（5％～16％）、超低的渗透率（0．007～2mD）、异常高的伽马值及较低的油层电阻率等不同于常规油层的特点，若利用常规的测井解释方法对致密油进行测井评价存在一定的困难。基于巴肯组岩心分析、扫描电镜等资料，对造成巴肯组特殊测井曲线形态的原因进行了研究，并提出了响应的储层参数计算模型：针对储层高伽马值的特点提出了利用钍伽马或者补偿中子～密度交会计算泥质含量，针对造成储层低阻的黄铁矿提出了相应的校正方法并结合西门度模型对储层的含油饱和度进行准确计算。用该模型对18口井资料进行了解释处理，测井解释储层参数与岩心分析结果较为匹配，应用效果较好，同时也为其他地区致密油储层的测井解释评价提供了一种可借鉴的方法。

Tight-oil is a typical of unconventional oil, which usually refers to the oil that exists in the carbonate or fragmental rock interlayer of the source rock or the oil that exists in the tight sandstone nearby the source rock. Bakken is the main formation for the tight oil in North America. It has the characteristics of low porosity （5%-16%）, low permeability （0.007-2mD）, abnormal high gamma and low reservoir resistivity which is different from that of conventional oil reservoir, so there still exists some difficulty if we evaluate the tight oil reservoir with the conventional logging evaluation method. Based on the core analysis data, scanning electron microscope data, the causes of abnormal curves for Bakken formation were studied and corresponding parameters calculation model were proposed： according to the high gamma characteristic of the log curve, no uranium gamma or neutron-density curve was used to calculate the volume of shale, and appropriate method was proposed to eorrect the low resistivity effect of the pyrite and simandoux model was used to calculate the oil saturation accurately.18 wells were evaluated by the model. We found there is good match between reservoir evaluation result and core analysis result, the evaluation method got good application result also. At the same time, the study also provides a useful method for tight oil reservoir well logging interpretation and evaluation of other areas.