Dissolution Simulation of Chang-8 Tight Reservoir in Jiyuan Area of Ordos Basin, China and Its Influencing Factors(PDF)
《地球科学与环境学报》[ISSN:1672-6561/CN:61-1423/P]
- Issue:
- 2017年第02期
- Page:
- 225-237
- Research Field:
- 基础地质与矿产地质
- Publishing date:
Info
- Title:
- Dissolution Simulation of Chang-8 Tight Reservoir in Jiyuan Area of Ordos Basin, China and Its Influencing Factors
- Author(s):
- WANG Qi; XU Yong; LI Shu-tong; SU Long; WANG Yang; YAN Can-can; MOU Wei-wei; LI Yang
- 1. National Engineering Laboratory of Exploration and Development on Low Permeability Oil and Gas Field, Xi’an 710018, Shaanxi, China; 2. Key Laboratory of Petroleum Resources of Gansu Province/Key Laboratory of Petroleum Resources Research of Chinese Academy of Sciences, Lanzhou 730000, Gansu, China; 3. University of Chinese Academy of Sciences, Beijing 100049, China; 4. State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China
- Keywords:
- tight reservoir; dissolution mineral; simulation experiment; fluid-rock interaction; X-ray diffraction; dissolution rate; Yanchang Formation; Ordos Basin
- PACS:
- P618.130.2
- DOI:
- -
- Abstract:
- Based on the study of the basic features of Chang-8 tight reservoir in western Jiyuan area of Ordos Basin, the process of dissolution reaction of rock and organic acid of Chang-8 reservoir was simulated by the fluid-rock interaction simulator of high temperature and pressure reservoir. According to the geological conditions, 0.15 mol.L-1 acetic acid solution with pH=2.65 was used as the reaction solution, the simulated temperature was the actual paleogeotemperature (87 ℃-103 ℃) corresponding with the depth of dissolution window, and the simulated pressure was 24.70-30.18 MPa. The reservoir features and dissolution rates of samples before and after the reaction were compared, and the dissolution features and influencing factors of Chang-8 tight reservoir were analyzed, and the dissolution process and porosity enhancement were discussed. The results show that under the action of acetic acid, the dissolution reaction of feldspars (albite and K-feldspar) and calcite minerals occurs obviously, and produces sediments; according to the relative dissolution rate of minerals, the dissolution velocity of mineral is larger than that of feldspar in whole, and that of calcite is larger than dolomite, and that of plagioclase is larger than potassium feldspar; with the increase of temperature and pressure, the dissolution rates of calcites remain unchanged after the first increase, and the dissolution rates of feldspar increase linearly, but the dissolution rates of calcite are higher than that of feldspars at the beginning; the dissolution process of tight reservoir is divided into three stages, including calcite cement dissolution process, feldspar dissolution process and sediment filling process after dissolution. Dissolution makes the pores of tight reservoirs increasing significantly, and is a main diagenetic type of tight reservoir porosity enhancement, and is also one of the key factors to find the “sweet spot” of tight reservoir.
Last Update: 2017-03-31