Alteration-destruction-preservation of bedrock weathering crusts and the influence on reservoir distribution in Dongying Sag, Bohai Bay basin

Abstract

The exploration potential of the bedrock reservoir is notably large, and clarifying the characteristics and main influencing factors of the bedrock reservoir is the premise of predicting the distribution of favourable reservoirs. This study describes the characteristics of bedrock reservoirs in Dongying Sag, Bohai Bay Basin, based on an integrated analysis of cores, thin sections, well logs, image logging, porosity and permeability data and oil testing data. The main influencing factors are determined from the aspect of alteration-destruction-preservation of bedrock weathering crusts based on outcrops, inter-well sections and seismic interpretation. Subsequently, the genetic model of the distribution of the bedrock reservoir is established based on the distribution characteristics of weathering crusts on different structural zones combined with the main influencing factors of weathering crusts. Furthermore, the distribution of favourable reservoirs is determined based on an integrated analysis of reservoir formation and preservation conditions. The main influencing factors and the genetic model of distribution for a bedrock reservoir based on analysis of the alteration-destruction-preservation aspect not only gives us a more comprehensive understanding of the evolution of bedrock reservoirs, but also provides new ideas and theoretical support for further exploration of bedrock reservoirs in other rift basins worldwide.