湖相页岩体油气赋存机制与含油气性定量表征

As kind of unconventional oil and gas resources form, lacustrine shale oil and gas has special significance for lake basins in eastern China. The mechanisms and quantitative representation of oil and gas occurrence in lake shale the main basis is the main basis to know mechanisms for oil and gas accumulation in lacustrine shale and to quantitatively evaluate shale oil and gas resources. This project is to make full use of geological and geochemical data and simulating experiment, comprehensively analysis and study geological and geochemical characteristics of the two sets of mature shale in the upper part of Member 4 and the lower part of Member 3 in Shahejie Formation in Paleogene system in Dongying and Zhanhua sags. On the analysis of the nature, spatial distribution and evolution rule of shale and shale oil and gas, using the measured geological sections and thermal simulation experiments under different condition, this project is to analysis the mineralogical composition and micro characteristics of pore structure of clay shale forming in different lacustrine deposition environment, detect the organic and inorganic function and porosity evolution in clay shale, study the influence of over-pressure on the accumulation and expulsion of shale oil and gas, discuss the conditions, mechanisms and modes of occurrence of lacustrine shale oil and gas, expound the typical characteristics of oil and gas accumulation in the self-generated and self-reservoired lacustrine shale, determine some key parameters for the quantitative characterization of the amount of oil and gas and bearing capability in lacustrine shale, show the geochemical process and accumulation resources potential for the shale oil and gas in the accumulating evolution, and provide a reference or basis for the exploration of continental lacustrine shale oil and gas in China.

湖相页岩油气作为非常规油气资源的一种形式，对我国东部湖相盆地具有特殊意义。湖相页岩体系中的油气赋存机制与定量表征是认识页岩油气成藏机理及对页岩油气资源定量评价的主要依据。本项目拟充分利用地质、地球化学资料和模拟实验等综合分析手段对东营和沾化凹陷沙四上亚段和沙三下亚段中两套成熟的页岩进行全面的地质和地球化学研究。在分析研究区湖相页岩及页岩油气空间分布、性质和演化规律的基础上，利用不同条件下的热模拟试验及实测地质剖面特征的分析，系统地分析不同湖相沉积环境下页岩的矿物学组成及孔隙结构微观特征，检测页岩中有机与无机作用及孔隙演化，研究超压对页岩油气聚、散行为的影响，探讨湖相页岩油气的赋存机制和成藏条件，阐明湖相页岩油气自生自储成藏的典型特征，确定一些定量表征湖相页岩中含油气性的关键参数，指明湖相页岩油气在成藏过程中的地球化学演变及资源潜力，为中国陆相湖盆页岩油气勘探提供参考或依据。

本项目以东营凹陷和沾化凹陷新生代古近系发育的大套页岩体作为研究中国东部陆相湖盆超压页岩油气藏的样本。通过低温液氮吸附、甲烷等温吸附、有机酸与泥页岩酸溶模拟和低温氮气介孔全分析等实验测试手段对东营凹陷的页岩样品进行了测试分析。.1、总结划分了东营凹陷和沾化凹陷古近系泥页岩类型，根据是否含有有机质、碳酸盐矿物及粘土矿物的含量将研究区泥页岩分为油页岩、钙质泥岩、灰质页岩、泥灰岩、粘土岩、页岩，并统计了各类型泥页岩厚度，进行了平面成图。. 2、实测分析了东营凹陷深层沙三下和沙四段泥页岩元素分布特征，建立了元素预测方程，并对部分其他井元素分布进行了预测。结果表明，微米级的溶蚀孔隙和蜂巢形的孔洞增强了泥页岩孔隙结构的连通性，粘土矿物中主要是伊蒙混层石和伊利石；预测矿物含量分布因沉积环境不同呈现出较强的非均质性。.3、研究了东营凹陷泥页岩的孔隙结构，探讨了孔隙发育的主控因素。研究结果显示，总体上泥页岩微观孔隙结构以利于储集的墨水瓶形为主，比表面和孔容都显示高值，孔径分布显示以微孔和介孔为主。孔径分布曲线呈现单峰形、双峰形和多峰形。孔隙类型可以分为有机质孔、粒间孔、粒内孔和微裂隙。.4、测试了东营凹陷泥页岩的吸附性能，建立了矿物与吸附性能之间的关系。比表面积和孔容都和吸附气含量呈正相关性，而孔径相反，墨水瓶形孔隙吸附气量远高于开放的平行板型孔隙。以伊利石为主的粘土矿物和石英与吸附气含量呈正相关，而高岭石、绿泥石及以方解石为主的碳酸盐矿物与吸附气量呈负相关。.5、通过东营凹陷泥页岩热演化模拟实验中的孔隙结构及地球化学指标变化，探讨了生烃演化过程中孔隙结构的参数的变化特征。结果显示，随着升温和热演化成熟度的升高，TOC含量逐渐降低，在生油的主力区间内，泥页岩的比表面积、微孔表面积、微孔体积和吸附量均升高。.6、发明了不同类型有机孔的预测方法，建立了定量预测单位烃源岩生烃量、生烃潜量、排烃量和排烃效率的方法，在此基础上形成了典型单井生烃和孔隙演化剖面，形成了对页岩油气非均质性分布的一套预测和评价技术。.相关结果对研究非常规泥页岩油气赋存机制、定量表征泥页岩含油气性的非均质性和评价非常规泥页岩油气资源有重要的意义。