Well Logging Identification Method Of Gas Reservoir In Sulige Field

Sulige gasfield lies in north of Ordos Basin, major gas reservoir is He 8 and Shan 1 layers of Neopaleozoic. Sulige gasfield is the largest discovered gasfield onland so far in China, expected ultimate reserves is 3x1012m3. Sulige gasfield is also the typifier of the low permeability tight sandstone gas reservoirs, physical property is bad, anisotropy is strong and gas/water relationship is complicate of the reservoir. The difference of diagenesis, pore configuration and pouring degree of gas seriously affected the ability which takes well logging data to identify and evaluate gas reservoir. In this dissertation, Aiming at the above questions, we study the causing mechanism of low resistivity gas zone, well logging identification method of gas reservoir, fluids rate forecast and etal. The main conclusions are as follows:(1) High porosity, high microporosity and the coexisting of filtrational por and micropore is the main reason which induce the causing mechanism of low resistivity gas reservoir. At the same moment, in some high permeability zone, the deep invasion of mud filtrate also reduce the resistivity.(2) According to genetic model of water in gas reservoir and existent situation of formation water, this paper divides the water bearing gas zone into three types:combined water, interstratum water, resident water. Indicating the main reason of gas reservoir containing water is vertical & horizontal anisotropic, displace insufficient irreducible water and retained water.(3) According to the well logging responding mechanism of gas, recognition methods of gas water layers, such as induction and laterologging combined interpretation method, cross plot method, gas survey method and so on are proposed, which make the logging interpretation coincidence rate of low resistivity oil reservoir raises from 70% to 85%, and acquires good effect.(4) Using semi-permeable baffle plate experimental apparatus, the regular pattern of lithological-electrical parameters in tight sandstone is studied, and the self-adaptive model of lithological-electrical parameters and the saturation model based on the sealed core data are established, which improves the accuracy of gas-bearing reservoir evaluation.(5) It researches the dynamical & statical and logging multi-parameters standard of fluids rate forecast, and achieves production of gas well quickly classify.