陆相页岩油含气性演化特征与成因机制及可动油评价方法

Significant achievements made by the United States in shale oil exploration have pointed out a new direction for the petroleum exploration in China. Although much progress has been made in the research of shale oil in China, no major breakthrough has yet been achieved in capacity. This is mainly caused by two factors. First, the mineral composition is different from that of foreign countries, resulting in poor fracturing effect and low yield. Second, the difference of characteristics of retained oil and gas between continental shales and marine shales makes it difficult to find high-yield desserts. The root cause is the low gas content which leads to high viscosity and insufficient internal energy to produce high yields. This study based on the second problem focuses on the continental shale in the third member of the Jiyang Depression in the Bohai Bay Basin. The objective of this study is to clarify the lithology, electrical measurement, drilling, logging, oil and gas water testing, and geochemical characteristics of shale formation and their relationships with retained hydrocarbon. Furthermore, this study tries to reveal the critical conditions and its controlling factors of large scale gasification of shale oil and to establish a quantitative model through physical simulation experiment and statistical analysis of retained hydrocarbon and bound hydrocarbon. This study also tries to reveal the relationship between shale oil mobility and gas content through geological analysis and physical simulation experiments and to propose a quantitative evaluation method, thus providing a scientific basis for finding high-yield dessert areas and dessert layers and deploying 2 exploration wells. The aims of the study also include cultivating 5 postgraduates and publishing 5 papers.

美国在页岩油勘探方面取得的重大成效为中国油气勘探指出了新方向，中国页岩油研究虽然取得诸多进展，但目前产能仍尚未获得重大突破，最主要问题包括两个方面：一是矿物组成与国外有差异，当前压裂效果不好，无法获得高产；二是陆相页岩滞留油气特征与海相页岩存在差异，寻找高产甜点遇到困难，根本原因是含气量少导致粘度大、内部能量不足无法获得高产。本项研究针对第二个问题展开深入研究，重点以渤海湾盆地济阳坳陷沙三段陆相页岩为研究对象，搞清相关页岩层系岩电特征、温压特征、地化特征、含油气特征与页岩滞留油气量的关系；通过开展页岩滞留（总）油气量与束缚（死）油气量的统计分析和热压模拟实验，揭示页岩油向页岩气转化的临界条件、主控因素、成因机制并建立定量关系模型；通过地质剖析和实验结果，提出页岩油含气性与可动油定量评价方法，为寻找高产甜点区和甜点层提供科学依据，通过实际应用，部署科探井2口，培养研究生5名，发表论文5篇。

陆相页岩的滞留油气特征与海相页岩相比存在明显差异，故直接套用和改进国外海相页岩油气的相关技术不能实现陆相页岩油气高效勘探开发，陆相页岩油气勘探开发需要新的理论和方法技术指导。厘清页岩成烃过程中油气滞留量与滞留特征及变化规律和成因机制，是陆相页岩油气有效资源评价和甜点预测的前提，对陆相页岩油气勘探开发具有重要意义。本研究首先基于原始页岩样品生烃特征和热模拟页岩生烃演化规律，揭示了陆相页岩演化过程中生油气量及其变化特征。在此基础上，进一步阐明了陆相页岩滞留烃成因机制，探讨了演化过程中滞留油气量与束缚油气量的变化规律，建立了热演化过程中泥页岩滞留油气定量计算模型及泥页岩含油气性演化的基本地质模式；然后，基于人工岩芯核磁共振驱替物理模拟实验，探讨了陆相页岩可动油分布的临界条件，明确了陆相页岩可动油主控因素，并建立了页岩油可动性定量评价方法。进而，对研究区沙三段陆相页岩油有利区进行了预测评价与探井部署。研究成果对于研究和评价页岩油可动性与可采性具有重要的现实意义。