Oil & Gas Geology ›› 2021, Vol. 42 ›› Issue (3): 702-716.doi: 10.11743/ogg20210315

• Methods and Technologies • Previous Articles     Next Articles

Pore evolution of the Permian Qixia-Maokou Formations dolomite in Sichuan Basin based on in-situ dissolution simulation experiment

Shiqi Liu1,2(), Senran Chen1,2, Bo Liu1,2,*(), Kaibo Shi1,2, Yuyang Liu3, Haofu Zheng4, Qingqing Luo1,2   

  1. 1. School of Earth and Space Sciences, Peking University, Beijing 100871, China
    2. Institute of Oil & Gas, Peking University, Beijing 100871, China
    3. Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, China
    4. Hehai College, Chongqing Jiaotong University, Chongqing 400074, China
  • Received:2020-12-21 Online:2021-06-28 Published:2021-06-23
  • Contact: Bo Liu E-mail:liushiqi17@pku.edu.cn;bobliu@pku.edu.cn

Abstract:

A hydrothermal diamond anvil cell (HDAC) equipped with a laser raman spectroscopy (LRS) and an optical microscope was used in an in-situ simulation experiment of dissolution-precipitation process between carbonate minerals (rocks) and pore fluid under continuous closed-open-closed cell (system) conditions that are typical of a deep burial process.In line with the actual geological conditions, the experiment was carried out on the Qixia-Maokou Formations dolomite samples from the Sichuan Basin and successfully generated acetic acid in closed cell through hydrolysis of acetic anhydride.The results show that dissolution occurs at the edge and cleavage of carbonate rock samples in a closed but periodically open system, and that the dissolution range is related to acid fluid flux.After entering the closed system, the relative ion concentration of solution was measured with the (semi-quantitative) Raman spectroscopy and indicates a precipitation tendency.The experimental results and the actual geological conditions of the Permian in the Sichuan Basin jointly indicate that the evolution of intergranular pores and intergranular dissolution pores of coarse-grained dolomites in the Qixia-Maokou Formations in southwestern Sichuan Basin conforms to the experimental simulation result and that transportation of ions in acidic fluids through tectonic fractures facilitates the redistribution of pores and materials through dissolution-cementation in the system.

Key words: Hydrothermal Diamond Anvil Cell (HDAC), in-situ simulation, pore evolution, dolomite, Qixia-Maokou Formations, Sichuan Basin

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