Stratigraphic water distribution pattern and main controlling factors in the southeastern part of Surig gas field

Southeast of Sulige gas field, through statistical analysis of the chemical properties and characteristics of formation water samples of Majiagou Formation 1 sub-section in Southeastern Sulige, revealing its results found that the formation water in Southeastern Sulige is highly mineralized, with an average of 148905.46mg/L, much larger than normal seawater, without a long time of intra-stratum circulation, highly metamorphosed evaporated brine after water-rock action with high concentration, and the water type of CaCl₂ type. pH value is between The pH value is between 5.0 and 6.3, which is weakly to moderately acidic, mainly related to the high content of residual organic acid in the formation water. The results of the analysis of various stratum water chemical parameters show that the stratum of Majiagou Formation 1 subsection in Southeastern Sulige is well closed, which is favorable for the preservation of the gas reservoir. Stratigraphic water is characterized by gas-water mixing, which is mainly distributed in five areas, with the west relatively "water-rich" and the east relatively "gas-rich". Vertically, according to the differences in genesis and spatial distribution pattern, the stratum water is divided into tectonic low-part water, isolated lens water, and low-permeability zone stagnant water. Tectonic low water is commonly found in the western part of the study area where the tectonic structure is relatively low and in the nasal concave area where the tectonic structure is relatively low in the southeast direction; the isolated lenticular water is relatively undeveloped. The study concludes that three factors, namely, tectonic pattern, reservoir inhomogeneity, and paleomorphic pattern, jointly control the distribution of gas and water in Southeastern Sulige, which is mainly affected by reservoir inhomogeneity and paleomorphic pattern, and the tectonic influence on the anisotropic effect of gas and water is limited.