Gas-water Distribution Of Tight Sandstone Gas Reservoir In He8 Formation In The Fifty-nine Block Of Sulige Gas-area

He8 formation is the main reservoir of fifty-nine block of Sulige gas-area, and it is a typical tight sand stone reservoir. The reservoir have a characteristic of large gas reserves and scattered distribution, most of the wells in the study area are gas-water wells. The inconsistencies in control factors of gas water distribution and water recognition methods, are the main bottlenecks in the exploration and development.So it is imperative to have a study of gas water distribution.Based on fine strata classification and correlation, four-property relationship should be find out while classification and criterion of the rock property models were built. Connecting with the research results before, NMR and chart correction method can be used for judging gas bearing capacity, and Achie formular can calculate out the gas content. then gas-water identification formulas can be established. Sandstone distribution, physical property and water saturation can be dipcted on plane. Then through experimental analysis, observing thin sections under microscope and electron microscope, representative samples can be selected for pore-throat structure, physical characteristics and diagenesis analyses. There is a certain relationship between rock mineral composition and granularity, the sandstone with different lithology,pore-throat structure have different way of densification and gas filling, and they are factors that influnce the accumulation and distribution of water and gas.Following conclusions could be drawn:(1) The weak hydrocarbon-generating intensity is the main factor of reservoir water production, sandbodies mainly developed in stacked channels. The low permeability and prosity petrophysical property of sandstone and frequent change of sedimentary microfacies make a strong heterogeneity in macro-and micro-structure, which contributed to the complexity of the gas-water distribution in the study area.(2) Lithic quartz sandstone was densified by compaction and siliceous cementation. Densification and gas filling happened almost in the same period. Lithic sandstone can finish its densitification only by compaction, thus gas filling start after densification.(3) The coarser grain size sandstone always with higher the content of quartz, better petrophysical properties property, higher hydrocarbon filling efficiency and gas saturation. Tiny pore structureand high clay content increased bound water content, lead to the phenomenon of low resistivity in gas-water layer.(4) Formation water gathered in relatively low structural positions, low permeability zone and lenticular isolated sand body.In conclution, the factors that control the gas water distribution are the physical property, pore structure, gas filling efficiency, stratigraphic structure and quality of hydrocarbon source rocks in the study area.