【作者】 钟勇；

【导师】 刘树根；

【作者基本信息】 成都理工大学 ， 矿产普查与勘探， 2011， 博士

【摘要】 我国中西部前陆盆地勘探显示其油气资源丰富,但是油气探明率较低。新方法、新技术的研究应用是加快前陆冲断带复杂构造地区油气勘探的重要手段。为克服前陆冲断带地震资料品质较差的限制,本文探讨应用断层相关褶皱理论、野外地质调查、钻测井资料联合约束地震构造解释和建模进行综合研究分析。本论文为探索川西前陆冲断带海相油气勘探方法,以大圆包地区为研究对象,根据“源盖控区、储层控层和圈闭控位”的勘探思路,运用地质-地球物理-地球化学相结合的手段,研究烃源岩的发育分布和油气的保存条件,确定有利勘探地区(源盖控区),研究勘探区内据优质储层的发育层系确定天然气的主要分布层系(储层控层),研究圈闭的发育特征确定气藏的存在部位(圈闭控位)。重点探讨研究了用于前陆冲断带复杂构造解释和建模技术方法的改进和应用。大圆包地区位于川西复合前陆盆地龙门山推覆造山带前缘,构造主要受控于通济场断层、关口断层、彭县断层三条区域性断层。关口断裂为安县—都江堰断裂向南部的延伸,为北西倾,断面上陡下缓呈犁式,地面无大的断距出露,且褶皱前翼倾角近于直立。由断层相关褶皱分析,关口断层末端形成构造三角楔,由于断层插入过程中顶部反向逆冲断层上盘地层褶皱诱发而成。关口断裂上盘的通济断裂形成最晚、强度大,将老地层推至地表。根据地震资料确定,主要正向构造带为位于通济场断层与关口断层之间的断褶构造带,发育大圆包构造。构造地质建模主要依靠建立地表地质剖面,地震地质层位标定解释和构造几何学建模与运动学分析。在地震资料解释过程中,将地震数据转换为地震图像,对地震图像进行地震断层解释,不依赖于原始地震数据体,并且可以将图像处理技术用于叠后地震资料解释。研究改进偏微分扩散方程图像增强算法,针对三维地震图像特征,改进图像结构张量提取方法,应用GPU (Graphic Process Unit)加速计算实现提取三维地震图像的三维结构张量,由结构张量导向进行图像扩散滤波增强预处理,实现三维地震图像降噪、横向分辨率提高、同相轴连续性增强和构造信息突出。通过GPU计算和CPU计算性能对比结果可以看出,应用GPU计算可以满足三维地震图像处理需求,有助于提高地震解释客观性和工作效率。通过训练神经网络对多种地震属性进行分类识别三维地震不连续体,用于辅助构造解释,结合地质资料和钻测井资料落实了大圆包地区多次滑脱构造特征。大圆包构造主体为二、三叠系。从白水河、通济场至关口一带须家河组内部的变形和断裂情况分析,白水河至思文场一带出露的须家河组属印支期推覆构造的上盘逆掩岩席,其前锋在晚三叠世末期已经出露地表,后被白田坝组覆盖。再从大圆包构造后翼印支期推覆断层面的后期改造形态,结合地面彭县向峨附近彭灌断裂下盘侏罗系的地面构造展布形态来看,该构造的性质应属早喜马拉雅期发育的二叠系断层转折褶皱。通过烃源条件分析,四川盆地海相领域主要烃源岩为下寒武统、下志留统、下二叠统和上二叠统烃源岩。陡山沱组和上二叠统煤系烃源对于龙门山前缘的贡献并不大,而下志留统烃源在川西地区缺失。因此,对龙门山前缘具有重要贡献的烃源层系应是下寒武统。通过流体特征分析显示,盆山结合部的冲断带内,流体呈活塞式向前陆盆地内渐展式侧向迁移,流体并未形成大规模侧向运移的趋势。冲断带内主滑面以下的地层相对于主滑面以上的冲断岩片具有相对较好的保存条件。前陆隆起区曾经有过石油和天然气的聚集与成藏,先后形成了古油藏、古气藏。形成古油藏与古气藏时,区域内具备保存条件；在印支-燕山期古油藏转变为古气藏,并且形成水溶性气藏；燕山末-喜马拉雅期,形成前陆隆起区古气藏的破坏、调整和重新成藏。通过中三叠统沉积演化研究其储层特征,传统中三叠统油气勘探重点关注的是台内滩发育的优质储层,LS1井T2l4和T2l3钙质海绵的发现,预示雷口坡组还有可能存在礁滩组合形成的优质储层,确定T2l3为研究目的层。通过地球物理方法对雷口坡组顶部膏岩研究分析,认为大圆包构造保存条件受到断层作用破坏,使得油气未能成藏。同时,预测关口断层下盘隐伏构造为有利勘探方向。更多还原

【Abstract】 In foreland basins of Central and West China, the exploration shows there is rich in hydrocarbon and has a lower rate of proven resources. The study of new method and the application of new technology, which are important to speed up the exploration of the complex tectonic belt in the foreland thrust belt. This paper discusses the seismic modeling for structural analysis of the foreland thrust belt in west Sichuan. Based on study of the Dayuanbao area, the hydrocarbon exploration methods is mapping source rocks and researching the hydrocarbon preservation conditions to determine favorable areas for oil and gas exploration, mapping the distribution of the high-quality reservoirs assemblage to determine the gas distribution layer, studying the trap development characteristics to determine the location of the gas reservoirs. At the same time, this paper focuses on the seismic modeling using3D seismic image and seismic attributes, and applied geophysical methods combination with the geological means for exploration of Dayuanbao area.Dayuanbao area is in the front of the Longmen mountains thrust belt, western Sichuan foreland basin. The main structure controlled by Tongjichang fault, Guankou fault and Penxian fault. Guankou fault is the extending southward of the Anxian-Dujiangyan fault, it is a northwestward plow fault, and within a thrust wedge tectonics at the fault terminal. Tongjichang fault is formed late and thrust to the ground. Based on the seismic images, the Dayuanbao structure is a positive structure between Tongjichang fault and Guankou fault.Seismic modeling relies on formed the surface geological sections, Seismic interpretation, geometry modeling and kinematics analysis of the tectonic. Seismic interpretation from3D seismic image volume, which can be processed without changing the original data, is more convenient. The volume of3D seismic image enables to enhancing process and then interprets directly. Based on PDE, eigenvalue analysis and edge detection, the faults of3D seismic image volume were interpreted with the computations accelerate with GPU (Graphic Process Unit) implementation. The practical application result shows that this method can effectively improve the objectivity and efficiency of the interpretation of3D seismic data.Neural Network Classification of multi-seismic attributes used to faults detection, which can help quick structure interpretation. Then, multiple detachment structure of the Dayuanbao was ascertained by geological and geophysical files. The main strata of Dayuanbao structure are the Permian and the Triassic. According to the research of the deformation and fracture of the Xujiahe formation from Tongjichang to Guankou, the outcrops of Xujiahe formation at Siwenchang and Baishuihe, it is belong to the hanging side of thrust sheet, and thrust to exposure in late Triassic period, then covered by Baitianba formation. It shows that the Dayuanbao structure is a fault-bend fold of Permian system in he early stage of Himalayan, which analyzed by the reconstruction form of the back limb of Dayuanbao and the spread pattern of the ground structure in Penxian area.Through the analysis of hydrocarbon source condition, the main hydrocarbon source of the marine strata in Sichuan basin, which are lower Cambrian, lower Silurian, lower Permian and upper Permian. The hydrocarbon source of the Doushantuo and upper Permian is less contribute to the front of Longmen mountains, moreover, the lower Silurian hydrocarbon source is deletion in west Sichuan. So, the main hydrocarbon source contribution to the front of the Longmen mountains should be lower Cambrian.The study of fluid characteristics shows that the fluid is gradually lateral migration from the combination of basin and mountain to the foreland basin. The lateral migration of the fluid is not a large-scale trend. There is better preservation conditions below the thrust belt compared with the thrust microlithon above the sliding plane. In foreland uplift area, there have been hydrocarbon gathering and accumulation, and has formed paleo-reservoir and paleo-gas-reservoir. At the same time, there were good preservation conditions. In the process of transforming paleo-reservoir into paleo-gas-reservoir between Indochina to Yanshanian, some pyrolysis gas dissolved into water and then formed water-soluble gas. The tectonic uplift occurred from late Yanshanian to Himalayan, which lead to the damage, adjustment and re-accumulation of the paleo-gas-reservoir. According to the reservoir characteristics of Middle Triassic sedimentary evolution, and the discovery of calcareous sponge in leikoupo formations, which indicate the T213is the target layer. By geophysical methods analysis of the gypsum in Leikoupo, it can be considered that the preservation conditions are destroyed which is the reason of failing to form reservoir. Then further study shows the prospective exploration area at the buried structure below the Guankou fault.更多还原