基于改进电成像孔隙度谱的海洋低孔低渗砂岩渗透率评价方法  

Permeability Evaluation Method for Marine Low Porosity and Permeability Sandstone Based on Improved Electrical Imaging Porosity Spectrum

作　　者：刘君毅 冯进 管耀 肖张波 王清辉 刘伟男 LIU Junyi;FENG Jin;GUAN Yao;XIAO Zhangbo;WANG Qinghui;LIU Weinan(Shenzhen Branch of China National Offshore Oil(China)CO.LTD.,Shenzhen,Guangdong 518000,China)

机构地区：[1]中海石油(中国)有限公司深圳分公司,广东深圳518000

出　　处：《测井技术》2023年第6期746-752,共7页Well Logging Technology

摘　　要：珠江口盆地南海东部海域陆丰凹陷恩平组和文昌组油藏以低孔隙度低渗透率(低孔低渗)砂岩储层为主,储层非均质性强、孔隙结构复杂,常规方法计算的渗透率精度难以满足勘探开发需求,而核磁共振测井纵向分辨率较低,难以有效识别优质薄层。针对上述问题,选择纵向分辨率较高的电成像测井,基于岩心实验和正演模拟结果,深入分析传统电成像孔隙度谱表征孔隙结构不足的原因,创新性地提出基于孔隙体积统计的孔隙度谱构建方法,通过与岩心核磁共振T2谱进行对比,改进后的孔隙度谱能够真实反映储层孔隙结构特征。在此基础上,参照核磁共振测井SDR模型的渗透率计算公式,构建基于改进孔隙度谱的渗透率计算模型。实际井评价结果表明,新方法较依据孔隙度渗透率关系的常规方法(孔渗关系法),计算的渗透率相对误差降低了66.4%,可以更有效识别出优质薄砂层,为油藏精细描述和产能评价提供可靠的基础数据。The reservoirs of Enping and Wenchang formation in Lufeng sag,Pearl River Mouth basin are mainly low porosity and low permeability sandstone reservoirs,with strong heterogeneity and complex pore structures.The permeability calculated by conventional methods is difficult to meet the actual needs of exploration and development,while the vertical resolution of nuclear magnetic logging is low,which makes it difficult to effectively identify high-quality thin layer.In response to the above issues,the author chose electrical imaging logging with higher vertical resolution,based on core experiment and forward modeling,after deeply analyzes the reasons for the shortcomings of traditional porosity spectrum in characterizing the rock pore structure,the author innovatively proposed a method for constructing porosity spectrum based on pore volume statistics.By comparing with core nuclear magnetic resonance T_(2) spectrum,the improved porosity spectrum can truly reflect the characteristics of reservoir pore structure.On this basis,referring to the SDR permeability calculation formula of nuclear magnetic logging,a permeability calculation model based on improved porosity spectrum is constructed.The actual well evaluation results show that the relative error of permeability calculation is reduced by 77.3% compared to conventional pore permeability methods,and it can more effectively identify highquality thin sand layers,which can provide reliable basic data for fine reservoir description and productivity prediction.

关 键 词：陆丰凹陷 低孔隙度低渗透率砂岩 渗透率 电成像 孔隙度谱 

分 类 号：P631.84[天文地球—地质矿产勘探]