泌阳凹陷深层致密砂岩孔隙结构测井评价方法研究

Logging Evaluation Method for the Tight Sandstone Pore Structure in Biyang Depression

泌阳凹陷安棚深层致密砂岩孔隙结构较为复杂,孔隙结构参数计算准确与否关系到储层评价是否正确有效。首先从Archie公式出发,提出井筒泥浆侵入近似等效为实验室高压压汞的设想,联合常规与核磁共振测井资料,通过公式推导研究了T 2谱转换为伪毛管压力曲线的新模型,然后利用岩心高压压汞实验数据对该模型进行标定,计算出储层孔径分布曲线、最大孔喉半径等孔隙结构参数。研究结果表明:新模型计算的孔隙结构参数与岩心实验分析结果相关系数均高于0.75,相对误差小于15%,具有较好的一致性。通过研究区新井资料跟踪处理和试气验证,该方法可有效识别出常规油层和差油层,证明了该方法准确性高。该方法为复杂储层的有效识别和评价提供了借鉴,具有较好的应用前景。

The deep tight sandstone in the Anpeng Formation of Biyang Depression is characterized by complex pore structure,and the reservoir evaluation is greatly dependent on the calculation of reservoir pore structure parameters.Based on the Archie formula,it is proposed that the wellbore mud intrusion is treated as the laboratory high-pressure mercury penetration test.According to the conventional and nuclear magnetic resonance logging data,a new model was provided to convert the T 2 spectrum into a pseudo-capillary pressure curve.Then the model was calibrated by the laboratory high-pressure mercury penetration test data.A series of pore structure parameters were calculated by this new model,including pore diameter distribution,maximum pore-throat radius,etc.Research indicates that the correlation coefficient between the calculated pore structure parameters by the new model and the laboratory core test data exceeds 0.75 and the corresponding relative error is less than 15%,which shows a favorable consistency.According to the new well data and gas testing data,conventional oil reservoir and poor oil reservoir can be effectively identified by this new method,which shows a high accuracy.This research could provide certain reference for the effective identification and evaluation of complex reservoirs,which shows a favorable application prospect.