基于岩石物理实验的凝灰质砂岩岩相-成岩相测井精准识别方法研究

Tuffaceous sandstone reservoirs have been an important domain in petroleum and gas development. Because of the comprehensive influence of volcanic and depositional process, lithofacies, diagenetic facies and their combination are very complex. They are hard to be recognized with well logs because of the ambiguous geological meaning of well log response. This has restricted petroleum and gas exploration and development in tuffaceous sandstones. What’s the influence mechanism for lithofacies–diagenetic facies combination on reservoir well log response in tuffaceous sandstones? What’s the accurate relationship between well log response and lithofacies-diagenetic facies combination? The above two problems are scientific key points of the interdiscipline between geology and well logging of tuffaceous sandstones. They are also key points in reducing the ambiguity in well log interpretation. To resolve the above scientific problems, petrology and well logging petrophysics experiments of real and artificial drilling cores are used in this study. This study can build a lithofacies classification scheme of tuffaceous sandstone which can reflect petrophysical characteristics of rocks, explore the influence mechanism of lithofacies–diagenetic facies combination on well log response, reveal the accurate relationship between well log response and lithofacies-diagenetic facies combination, resolve the geological ambiguity in well log interpretation and build accurate methods for lithofacies-diagenetic facies combination recognition with well logs in tuffaceous sandstone. This study is exploration of the interdisciplinary domain between geology and well logging of tuffaceous sandstones. It has significant scientific and academic value. Meanwhile, it can be widely used in petroleum and gas exploration and development and has great social and economic value.

凝灰质砂岩已成为重要的油气开发新领域，在火山作用和沉积作用双重影响下，凝灰质砂岩岩相、成岩相及其组合复杂，测井响应多解性强，识别难，制约了其油气勘探开发。凝灰质砂岩中岩相-成岩相组合对储层测井响应的影响机制是什么？岩相-成岩相组合与储层测井响应间怎样精准对应？这两大问题是凝灰质砂岩储层地质与测井学科边缘交叉的科学关键，也是降低其测井解释多解性的核心。针对上述科学问题，本申请利用真实岩心、人造岩心的岩石学和测井岩石物理实验，构建反映储层测井岩石物理特征的凝灰质砂岩岩相分类，探索凝灰质砂岩岩相-成岩相组合对储层测井响应的影响机制，揭示岩相-成岩相组合与测井响应的精准对应关系，破解其测井响应多解性难题，建立凝灰质砂岩岩相-成岩相的测井精准识别方法。本申请是对凝灰质砂岩地质和测井学科边缘交叉研究领域的探索，具有科学探索意义和学术价值；同时在油气勘探开发领域有广阔应用前景，社会经济价值显著。

本研究以塔南凹陷下白垩统南屯组和铜钵庙组凝灰质砂岩低渗透复杂储层为对象，针对其岩相、成岩相及组合复杂，测井响应多解性强、识别难的问题，以测井岩石物理实验为基础，建立凝灰质砂岩储层测井精准解释方法，取得几点成果及认识：.1.基于实验分析建立了不同岩相、成岩相测井响应知识库，明确了不同储层的测井响应特征。.2.研究区砂岩含火山碎屑物质，岩性及测井响应特征复杂，建立了4种适合研究区低岩-电对比度砂岩的测井岩性识别方法。其中，针对火山碎屑物质蚀变对测井岩性识别的影响，建立了蚀变识别、蚀变校正、曲线构建三步的测井曲线重构法；将希尔伯特变换应用于测井高分辨率处理，并与纵向分辨率匹配法结合，提高了岩性测井识别精度；提出了改进的蜘蛛网图法，引入角度相似度，实现了复杂岩性的测井有效判别。.3.在研究区非储层中，识别出高伽马储层这一新的储层类型，揭示了其地质成因，指出岩石中放射性火山物质和粘土矿物吸附的放射性有机质对储层测井响应的影响，采用GR-Pe法实现了利用常规测井资料有效识别高伽马储层。.4.针对复杂储层参数测井定量解释难题，建立了高伽马砂岩复杂储层中火山碎屑含量、微观孔隙结构参数、储集空间类型测井定量识别与解释的新方法，为分析岩性、储集空间类型对物性、含油性的影响奠定了基础，解决了非取心井段储层微观孔隙结构评价难题。.本研究揭示了凝灰质砂岩岩相-成岩相组合与测井响应的精准对应关系，建立了凝灰质砂岩储层的测井解释方法，为凝灰质砂岩油藏勘探开发提供了准确的储层参数，应用前景广阔。依托本项目申报国家发明专利6项，已授权3项，出版专著3部，发表会议论文2篇，会议报告2次，期刊论文5篇，获得中国石油和化学工业联合会科技进步一等奖1项。