Primary depositional and diagenetic processes exert very important influences on shale gas reservoirs. Rock electrical properties are an important basis for making reservoir prediction using the electromagnetic method (EM). However, there is still a lack of understanding about the impact of the sedimentary diagenesis process on shale electrical properties, this study focuses on the impact of diagenesis on rock properties. In this study, rock electrical properties are studied based on electromagnetic experiments. We systematically studied the lithofacies of different depositional paleoenvironments and diagenetic processes, and the influence of diagenetic evolution on the rock electrical properties was discussed, by means of X-ray diffraction (XRD) analysis, field-emission scanning electron microscopy (FE-SEM), low-temperature nitrogen adsorption (LTNA), and trace element (TE) geochemical analysis. Based on the study of mineral composition, grain assemblages and pore systems, we identified four lithofacies in the Longmaxi Formation: siliceous shale, siliceous-argillaceous mixed shale, silty shale and argillaceous shale. Redox proxies (U/Th, V/Cr, and Ni/Co) indicate that the siliceous shale was deposited in a relatively anoxic and reducing environment, indicating a deep-water shelf depositional paleoenvironment. The siliceous-argillaceous shale, silty shale and argillaceous shale were deposited under a relatively dysoxic-oxic environment, indicating a shallow-water shelf depositional paleoenvironment. The order of resistivity values of the lithofacies within the Longmaxi Formation is 36.78 Ω m (siliceous shale), 66.81 Ω m (siliceous-argillaceous mixed shale), 79.54 Ω m (silty shale), and 107.00 Ω m (argillaceous shale), and the resistivity decreases with an increase in porosity. The siliceous shale has the most abundant authigenic quartz, which filled the primary pores forming a rigid framework during the gas window, inhibited compaction, increased the distribution of organic matter (OM), and enhanced the development of OM pores. The high TOC content and high maturity of siliceous shale at the bottom of Longmaxi Formation make the OM pores more developed. Pyrite, conductive fluid and pore network under the main control of OM pores in shale form a conductive circuit when AC voltage is input, which increases the exchange capacity of cations and leads to the phenomenon of low resistivity. The interconnected OM pore network, both depositionally and diagenetically derived, affects the electrical properties of the Longmaxi shale. This study reveals that electrical properties of shale rocks and its variations can be impacted by the depositional environment and diagenetic processes. This work provides resistivity parameters for the electromagnetic exploration of shale gas under complex terrain conditions and provides a theoretical basis for later interpretation.

原生沉积和成岩过程对页岩气储层具有非常重要的影响。岩石电学性质是利用电磁法（EM）进行储层预测的重要依据。然而，对于沉积成岩作用对页岩电性的影响仍缺乏认识，本研究重点关注成岩作用对岩性的影响。在这项研究中，基于电磁实验研究了岩石电学性质。采用X射线衍射（XRD）分析、场发射扫描电镜（FE-SEM）等手段，系统研究了不同沉积古环境的岩相和成岩过程，探讨了成岩演化对岩石电学性质的影响。 , 低温氮吸附（LTNA）和微量元素（TE）地球化学分析。在矿物组成、颗粒组合和孔隙系统研究的基础上，确定了龙马溪组4个岩相：硅质页岩、硅质-泥质混合页岩、粉质页岩和泥质页岩。氧化还原代表物（U/Th、V/Cr和Ni/Co）表明硅质页岩沉积在相对缺氧和还原的环境中，表明为深水陆棚沉积古环境。硅质-泥质页岩、粉质页岩和泥质页岩沉积在相对缺氧-好氧的环境下，表明为浅水陆棚沉积古环境。龙马溪组岩相电阻率值顺序为 36.78 Ω·m（硅质页岩）、66。81 Ω·m（硅质-泥质混合页岩）、79.54 Ω·m（粉砂质页岩）、107.00 Ω·m（泥质页岩），电阻率随孔隙度的增加而降低。硅质页岩中的自生石英含量最多，在气窗期充填原生孔隙，形成刚性骨架，抑制压实作用，增加有机质（OM）分布，促进有机质孔隙发育。龙马溪组底部硅质页岩 TOC 含量高、成熟度高，使 OM 孔隙更加发育。在交流电压输入时，以页岩中 OM 孔隙为主控制的黄铁矿、导电流体和孔隙网络形成导电回路，增加了阳离子交换容量，导致低电阻率现象。相互连接的 OM 孔隙网络，沉积和成岩作用均影响龙马溪页岩的电学性质。该研究表明，页岩的电学性质及其变化可能受到沉积环境和成岩过程的影响。该工作为复杂地形条件下的页岩气电磁勘探提供了电阻率参数，为后期解释提供了理论依据。