Reservoir Characteristics of the Chang 63 Sub-member in the Daluogou Area

Abstract

The Chang 6 reservoir is characterized by "five lows and one strong": low porosity, low permeability, low temperature, low pressure, low oil saturation, and strong heterogeneity. With the continuous and in-depth development of the tight oil reservoir in the Chang 6 formation of the Dagugou area, the natural energy depletion development method has led to severe formation energy deficit, rapid production decline, and difficulties in maintaining stable production, which have become "bottlenecks" restricting the sustainable development of this area. Deepening the understanding of the Chang 6 formation in the Dagugou area through reservoir characteristic research is an effective approach to break through the development bottlenecks and achieve increased and stable production. This study utilizes scanning electron microscopy, cast thin sections, high-pressure mercury intrusion, physical property analysis, oil-water two-phase flow experiments (unsteady-state), and nuclear magnetic resonance movable fluid experiments to investigate diagenesis, reservoir physical properties, and pore structure. It analyzes the microscopic pore structure characteristics of different parts of the sand body and different sand belts, examines the controlling factors influencing reservoir physical properties, conducts a comprehensive reservoir evaluation, and maps the planar distribution of reservoir physical properties to determine the distribution patterns of high-quality reservoirs. This provides theoretical guidance for the subsequent development of the tight oil reservoir in the Chang 6 formation of the Dagugou area.