Characterization of Glutenite Reservoir based on Digital Core Technology: A Case Study of Upper Wuerhe Formation in Mahu Depression.

Exploring the sensitivity of reservoir is the foundation of oil and gas exploration and exploitation. The damage degree of water sensitivity is affected by the clay mineral content and microscopic pore throat structure of the illite/smectite mixed layer. This study proposed a method for reservoir characterization based on digital core technology to reveal the influence of clay mineral content and micropore structure on the production of the illite/smectite mixed layer. The micropore throat characteristic parameters of the reservoir were obtained by using high-resolution micro computed tomography technology. The mineral quantitative analysis technology was used to determine the clay mineral content of the illite/smectite mixed layer. The distribution characteristics, pore radius distribution characteristics, throat length distribution characteristics, shape factor, and coordination number of the clay minerals of the illite/smectite mixed layer of the glutenite reservoir were analyzed. With the Upper Wuerhe Formation in Mahu Depression as an example, the accuracy of the proposed evaluation method was verified on the basis of the production data. Results show that the clay mineral content in the illite/smectite mixed layer and the increase in production are negatively correlated. The output of the area with the clay mineral content less than 30% in the illite/smectite mixed layer gradually increases. High-quality reservoir has the following microscopic pore throat characteristics: the distribution frequency of coordination number 5 exceeds 0.12, the average pore radius is greater than 6.34 µm, and the average throat length is greater than 8.58 µm. This study provides new technical methods and study ideas for understanding the sensitivity characteristics of glutenite reservoirs. [ABSTRACT FROM AUTHOR]