Discovery and significance of subtle buried hills in Jiyang Depression, Bohai Bay Basin

Abstract

The exploration of carbonate buried-hills in the Lower Paleozoic in the Jiyang Depression of the Bohai Bay Basin are at a minimum now, and the exploration targets are not clear. Hydrocarbon accumulation conditions were analyzed, especially the effectiveness of traps, which broke the shackles of traditional accumulation models and achieved exploration success. Three new buried-hill reservoir models have been discovered, namely the Chengbei 313 negative structure, the Chengbei Guxie 14 slope, and the Chengjiazhuang laterally adjacent high-permeability reservoirs. These three new models make the buried-hill negative structure, the slope zone with poor trap effectiveness, and the laterally unblocked buried hill fault blocks that were considered to have no exploration potential earlier become favorable exploration targets. The effectiveness of traps was analyzed from the aspects of fault activity characteristics. At the same time, a development model of 'sand-like mudstone' buried hill reservoirs was provided, which provided a new idea for the effectiveness analysis of buried hill traps.

Keywords

• reservoir pattern
• negative structure
• slope
• laterally docked high-permeability reservoir
• fault block
• analogous sand-mud pattern
• jiyang depression
• bohai bay basin