Abstract:
In order to study the different types and formation causes of reservoirs in the marginal zone of the Lianglitage Formation in the Katake Uplift, this study analyzed the marginal zone sedimentary reservoir characteristics, and their main controlling factors by utilizing a plethora of data sources including thin sections, core samples, FMI logging, and seismic data. The results show that the high-energy reef-flat facies of the Lianglitage Formation are distributed in a strip along the No.1 fault zone, exhibiting perplexing distribution patterns. The marginal zone also displays varying sedimentation patterns from east to west, which can be divided into three types of margin facies: fault-controlled narrow and steep, sedimentary steep slope, and sedimentary wide-gentle. Corresponding to these are three types of reservoirs: fracture-pore type, fracture-pore and pore type, and low-permeability fracture type. There are differences in the contribution of three constructive diagenetic processes, including quasi-syngenetic karstification, shallow-burial fresh water dissolution, and structural damage, to the formation of reservoirs in different locations of the marginal zone. The main controlling factors for the formation of the fault-controlled narrow and steep margin facies reef-flat superimposed bodies, karstification period faults, and late-stage fault activity. The sedimentary steep slope margin facies are found to be reef-flat superimposed bodies and northeast-trending strike-slip faults. The sedimentary wide-gentle margin facies are found to be karstification period fault activity and late-stage strike-slip faults. These results offer evidences for the exploration of marine carbonate reservoirs.