Organization
SINOPEC Exploration Company, Chengdu, Sichuan 610041, China
摘要
随着评价和开发技术的不断进步，陆相页岩油气已成为我国未来重要的接替能源。近期，川东南綦江地区部署的多口过路井在中侏罗统凉高山组页岩段钻遇了良好的油气显示。为明确该区页岩油气基本地质特征，以川东南綦江地区凉高山组富有机质页岩为研究对象，在岩心观察和化验分析的基础上，开展了綦江地区凉高山组二段页岩油气基础地质条件评价，并结合优质页岩地震预测、构造保存条件评价，落实了勘探潜力，指明了下一步勘探方向。以綦江典型井为例，综合有机地化特征、热演化程度、储层物性特征及含油气性特征等，对该区页岩油气进行了资源潜力分析。结果表明，綦江地区凉高山组二段下亚段优质页岩分布面积大，达4 569 km2，厚度20~39 m，受半深湖相控制，有机碳含量平均为1.3%~1.6%，有机质类型以Ⅱ1—Ⅱ2为主，镜质体反射率为1.00%~1.29%，生烃潜力大，实测含油气性好；优质页岩具有明显的高GR、高声波、低密度特征，结合地震波形分类和波阻抗反演技术，明确平面上丁山—东溪—关圣场地区最厚；发育宽缓稳定向斜，钻井普遍见良好油气显示，保存条件整体较好，主体埋深1 000~3 500 m，构造应力单一，可压性好。综合分析认为，綦江地区凉高山组陆相页岩具备良好的物质基础，保存条件好，页岩油总资源量超5亿吨，勘探潜力大。评价过程为持续扩大四川盆地陆相页岩油气勘探场面提供了研究思路。
Abstract
Advancements in evaluation and development technologies have established continental shale oil and gas as vital future alternative energy sources for China. Recently, exploratory wells drilled in the Lianggaoshan Formation shale segment of the Middle Jurassic in the Qijiang area, southeastern Sichuan, have shown promising oil and gas indications. To clarify the basic geological characteristics of shale oil and gas in this area, the organic-rich shale of the Lianggaoshan Formation in the southeastern Qijiang area was chosen as the subject of study. Based on core observations and laboratory analyses, an evaluation of the basic geological conditions for shale oil and gas in the second section of the Lianggaoshan Formation in the Qijiang area was conducted. This was combined with high-quality shale seismic prediction and structural preservation condition assessments to identify exploration potential and direct future exploration efforts. Using typical wells in the Qijiang area as case studies, resource potential analysis was performed by integrating organic geochemical characteristics, thermal maturity, reservoir physical properties, and oil and gas bearing characteristics. Results indicate that the high-quality shale in the lower subsection of the second member of the Lianggaoshan Formation spans an extensive area of 4 569 km2, with thickness ranging from 20 to 39 m. Controlled by semi-deep lacustrine facies, this shale exhibits an average organic carbon content of 1.3% to 1.6%, with organic matter types predominantly Ⅱ1 to Ⅱ2, and vitrinite reflectance values between 1.00% and 1.29%. These characteristics suggest significant hydrocarbon generation potential and promising measured oil and gas content. The high-quality shale is characterized by high gamma-ray (GR) readings, high acoustic time difference, and low density. Seismic waveform classification and acoustic impedance inversion techniques identified the Dingshan, Dongxi, and Guanshengchang areas as regions of concentrated shale thickness. These areas feature large, broad, and gentle synclines with favorable drilling results, indicating good overall preservation conditions. The main burial depths ranges from 1 000 to 3 500 m, with uniform structural stress and good compressibility. In summary, the analysis indicates that the continental shale in the Lianggaoshan Formation of the Qijiang area possesses favorable preservation conditions and substantial shale oil resources exceeding 500×106 t, offering significant exploration potential. This evaluation provides a strategic framework for expanding exploration efforts in continental shale oil and gas within the Sichuan Basin.
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