Discussion on prospecting shale oil potential of Mesoproterozoic Hongshuizhuang Formation in the Jibei Depression

Abstract

In order to evaluate the shale oil prospecting potential of the Mesoproterozoic Hongshuizhuang Formation in the Jibei Depression, the analyses of routine Rock-Eval pyrolysis, matrix porosity and permeability, mercury intrusion and nitrogen adsorption, argon ion polishing SEM and X-ray diffraction of bulk rock of typical core samples were carried out in this study. The shale oil forming conditions of the Hongshuizhuang Formation were studied, the shale oil resource was assessed, and the prospecting potential was discussed based on previous results. The results show that the lagoon facies black shale in the middle section of the Hongshuizhuang Formation is mainly 35-55 m thick with organic matter types of Ⅱ1 and Ⅱ2, and is a set of good- to excellent-quality source rock. The equivalent vitrinite reflectance of organic-rich black shale is 0.80%-1.25%. The matrix porosity is mainly 1.0%-8.0%, and the matrix permeability is (2-100)×10-6 μm2. The pores are dominated by inorganic pores and fissures with the diameter of pore larger than 50 nm. The values of S1 after recovery is mainly 1.60-6.50 mg/g, and the content of residual hydrocarbon gas distributes 0.13-0.24 m3/t, indicating good hydrocarbon potential. The average content of brittle minerals is 61.9%-72.3%, with good frangibility. The shale oil geological resource is about 12×108 t, and the shale oil recoverable resource is about 0.72×108 t for organic matter rich shale of the Hongshuizhuang Formation. These suggested that the organic matter rich shale of the Hongshuizhuang Formation in the Jibei Depression has a resource basis for shale oil exploration with good prospecting potential.

Keywords

• resource potential
• prospecting potential
• shale oil
• hongshuizhuang formation
• mesoproterozoic
• jibei depression