基于测井资料的南海天然气水合物储层识别与参数计算

Logging identification and evaluation of gas hydrate reservoirs in the South China Sea

南海浅层天然气水合物资源潜力巨大,由于天然气水合物储层的分布的不连续性和非均匀性,极大地制约了天然气水合物储层的测井评价,如何利用测井资料和岩心分析数据对天然气水合物储层进行准确识别和定量评价仍然是目前面临的一个关键技术问题.利用常规交会法、粒度中值和正态分布法识别天然气水合物储层并建立了判别标准,利用岩心数据与自然伽马值进行回归分析并建立泥质含量模型,对孔隙度计算模型进行了泥质含量的校正和优化,并利用声波资料对饱和度进行了计算和评估.结果表明:泥质含量模型精度检验的相对误差为5.3%,采用泥质校正后的密度计算孔隙度结果更加准确;BGTL模型计算出来的饱和度与岩心饱和度吻合较好,相对误差在8%以内.通过实际资料的验证与分析,表明所建立的天然气水合物储层识别与评价方法对南海浅层的天然气水合物储层有较好的适用性,能为下一步的勘查开采提供借鉴.

The shallow gas hydrate resources in the South China Sea have great potential.Because of the discontinuity and nonuniformity of hydrate reservoir distribution,the logging evaluation of hydrate reservoir is greatly restricted.How to use logging data and core analysis data to accurately identify and quantitatively evaluate hydrate reservoir is still a key technical problem.The conventional intersection method,median particle size and normal distribution method are used to identify hydrate reservoir and establish the discrimination standard.The shale content model is established by regression analysis of core data and natural gamma value.The shale content calculation model is corrected and optimized,and the saturation is calculated and evaluated by acoustic data.The results show that the relative error of shale content model accuracy test is 5.3%,and the porosity calculated by density after shale correction is more accurate;the saturation calculated by BGTL model is in good agreement with core saturation,and the relative error is within 8%.Through the verification and analysis of the actual data,it shows that the established gas hydrate reservoir identification and evaluation method has good applicability for the shallow gas hydrate reservoir in the South China Sea,and can provide reference for further exploration and exploitation.