Movable Condition Research Of Pore Water In Sulige Gas Field

Sulige gas field is a typical lithologic gas reservoir with low permeability, and the phenomenon of water production exists to some degree during the reservoir development. However, the sources of output water and movable condition of pore water are still not clear, which brings severe affect to the development effect and progress of gas field.On the basis of production status and gas-water distribution pattern analysis in the eastern Sulige gas field, and combined with the testing, production, logging and hydrochemical analyse data, it can be concluded that the output water of the study area is mainly of primary sedimentary water from He8 reservoir. The seepage law of the gas under irreducible water state and gas-water two-phase flow experiments demonstrate that the eastern Sulige gas reservoir is a water wetting reservoir. As the irreducible water saturation became higher, nonlinear seepage flow was much more obvious and gas seepage resistance became stronger. we did the research on the mobility of primary sedimentary water through the core flooding test under high pressure, nuclear magnetic resonance(NMR) and stress sensitivity experiment. The experiment results show that the value of T2 cutoff obtained from NMR experiment can directly reflect the irreducible water saturation of the sample. The pore water is the irreducible when the value is less than T2 cutoff, otherwise the pore water is movable. For the same cores, the stronger the displacement pressure is, the more water was drived from the sample and the better fluidity the pore water has; for the different cores, the higher porosity and permeability is, the greater mobility the primary sedimentary water has. Thus, the mobility of the primary sedimentary water is closely related to the prosity, permeability and displacement pressure of the sample. The moveable water saturation obtained from the experimental shows the characteristics of water producing of the low permeability sandstone gas reservoir effectively.This research makes an objective cognition and evaluation of the movable condition of primary sedimentary water in eastern area of Sulige gas field, which can provide reasonable basis for building capacity efficiently of gas field.