Study on diagenesis and diagenetic evolution of reservoir in Wuerxun depression

Abstract

Wuerxun depression is one of the main oil-bearing depressions in the middle of the Hailar District Basin with high exploration degree. With the deepening of exploration degree, the pore structure and distribution law of tight reservoir in trough are not clear. In this paper, through the combination of quantitative and qualitative, micro and macro, following the idea of “phenomenon characterization, essence exploration, law summary”, the diagenesis analysis and diagenetic evolution of tight reservoirs are studied to find areas with relatively good reservoir properties in the depression, which provides theoretical basis for tight reservoir exploration. Diagenesis controls the formation, evolution and distribution of the reservoir. The diagenesis of the reservoir in this area mainly includes compaction, cementation and dissolution, thus forming five kinds of secondary dissolution pores (intergranular dissolution pore, feldspar and debris dissolution pore, mold pore, interstitial dissolution pore and dissolution fracture). Vertically, the physical properties of the reservoir are generally poor, but the reservoir is well developed locally. The reservoir is well developed at 1300-1900m and 2300-2700m in Wuerxun depression.