ABSTRACT
The lower Paleozoic in the east of the Jingbian gas field is a set of quasi syngenetic dolomite fracture cave reservoir. Lithology is relatively dense, solution pores are not developed, most reservoirs only develop intergranular pores and pinholes, while fractures and microfractures are generally developed. The study area is close to the Jingbian gas field, but it has not been developed on a large scale so far. The water output of production wells is generally the main factor restricting its effective development. Based on the data of core observation, thin section, scanning electron microscope, imaging logging, and water quality analysis, this paper considers that: (1) the reservoir sealing conditions are good, the produced water has the characteristics of formation water, and the water volume increases sharply with the decrease of formation pressure; (2) The lower Paleozoic reservoir is located in karst depression and is generally dense, the natural gas filling and pore water displacement are insufficient, the gas water difference is not obvious, and there is no unified gas-water interface,; (3) The combination of reservoir fractures and holes forms the network channel of reservoir fluid migration, which is an important condition for water production; (4) When taking reservoir reconstruction measures for this kind of fracture cavity tight reservoir, the scale should not be too large and it is easy to communicate with distant fractures.
