层序地层格架及其对页岩储层发育特征的影响-以四川盆地龙马溪组页岩为例

为研究海相页岩沉积层序及其对页岩储层发育特征的控制作用，通过露头、岩芯研究及地化测试、有机质测试、矿物组分测试、孔隙发育特征测试等室内分析测试，结合测井小波分析，综合建立四川盆地龙马溪组的层序地层格架，并结合储层发育特征探讨层序与储层发育特征的关系。研究表明:研究区龙马溪组发育有两个三级层序；结合多口钻孔通过测井小波分析构建了研究区的高分辨率层序地层格架，识别出四个中期旋回A~D；对比各旋回内的储层发育特征，旋回A储层岩石学特征与旋回B~D存在显著差异，表现为储层有机质含量更高、水平层理更为发育、脆性矿物含量更高、微观储集空间（微—纳米级孔隙与微裂隙）发育程度更好，显示了层序旋回与储层物质成分、结构、力学脆性、含气性特征的显著相关关系，说明层序旋回是储层物性与含气性等发育特征的重要影响因素。基于前述研究，讨论了层序地层格架对储层发育的控制机理，层序格架下各旋回内沉积环境与沉积条件的差异导致储层沉积构造、物质成分与分布的差异，进而影响储层物性与含气性等特征；沉积盆地内高分辨率层序格架的建立可以为储层对比、评价与资源预测提供时间框架。建立了通过测井小波分析高分辨率层序地层格架进行储层分析对比的新方法，提出了基于储层小层分析建立页岩储层精细评价的新工作流程，有助于减少人为因素干扰，可以为页岩优质储层成因研究及其预测评价提供科学依据与新思路。

Sequence Stratigraphic Framework and Its Influence on the Development Characteristics of Shale Reservoirs: Taking the Longmaxi Formation shale in the Sichuan Basin as an example

To explore marine shale sedimentary sequences and their control on shale reservoir development characteristics, the sequence stratigraphic framework of the Longmaxi Formation in the sichuan Basin is synthetically established through the study of outcrops and cores in combination with experimental analysis (including a geochemical test, organic matter test, mineral composition test, pore development characteristics test, etc.) and logging wavelet analysis. The relationship between the sequence and reservoir development is also discussed in combination with the experimental study of the reservoir characteristics. The research shows that there are two third-order sequences and four mid-term cycles, A-D, developed in the Longmaxi Formation shale strata in the study area, and high-resolution sequence stratigraphy framework is established based on logging wavelet analysis of multi-cores in the study area. There are significant petrological differences between reservoirs of Cycle-A and Cycles B-D. The results show that the content of organic matter and brittleness micerals in Cycle A is higher, the horizontal bedding is more developed, and the microcosmic storage space (Micro-nano-scale pores and micro-fractures) is more developed than Cycles B-D. The correlation between the sequence cycle and reservoir composition, structure parameters, mechanical brittleness indexes, and gas-bearing characteristics indicates that sequence cycle is an important influencing factor for reservoir physical properties and gas-bearing capacity. Based on the experimental and analytical research results, the controlling mechanism of sequence stratigraphic framework on reservoir development is discussed. The differences of sedimentary environment and sedimentary conditions in each sequence cycle under the sequence stratigraphic framework lead to internal differences of sedimentary structure, material composition, and their distribution, affecting reservoir characteristics. The establishment of high-resolution sequence framework in sedimentary basins can provide a time frame for reservoir correlation, evaluation, and resource prediction. The establishment of logging high-resolution sequence stratigraphic framework based on logging wavelet analysis is helpful in reducing the interference of human subjectivity and provides a scientific basis and new approach for studying the genesis and prediction of high-quality shale reservoirs. Also, a new sequence framework-based workflow of reservoir characterization and evaluation for a shale reservoir is proposed based on reservoir internal analysis and evaluation.