The Production Model Research Of Horizontal Well And Development Index Evaluation In Sulige Tight Gas Reservoir

The pore throats is very fine and connate water saturations is very high for tight gas reservoir of Sulige. The stress sensitivity, the impact of the connate water on the stress sensitivity, the threshold pressure gradient and the horizontal well production model were carried out. The main research results are as follows:(1) The stress sensitivity experiment method which was suitable for the Sulige tight gas reservoir is proposed. The stress sensitivity of tight gas reservoir is strong, it increases with the permeability decreases. The bound water has a significant impact on stress sensitivity. The stress sensitivity is stronger with water saturation increases.(2) The main factors affecting the slippage effect in the tight gas reservoir are studied. The slippage factor has exponential relationship with permeability. The slippage effect is obvious with the decrease of permeability. The critical pressure at which the slippage effect disappears will decrease with permeability increases.(3)The variation laws of threshold pressure gradients at.different bond water saturations of the tight gas reservoir are studied. The threshold pressure gradients increases with water saturations increase, and increases with the permeability decreases. The function to describe the relationship between threshold pressure gradients and both water saturations and permeability is established.(4)The fractured horizontal well production model which considers length-width ratio of sand body, stress sensitivity, and threshold pressure effect is established. For a certain sand body area, the bigger the length-width ratio the lower of well gas production. The bigger the pressure drop the stronger the permeability sensitivity and the lower of well gas production. The bigger the threshold pressure gradient the lower the gas production.(5) Based on the production models established in this paper, the development indexes were evaluated. Fractured horizontal wells can obviously improve the reasonable productivity in a certain stable production period. The bigger the permeability, the reservoir thickness and sand body area the higher the well gas production. But the bigger the length-width ratio of sand body, stress sensitivity coefficient and threshold pressure gradient the lower the reasonable productivity and ultimate recovery rate. The appropriate reduce of the abandoned bottom-hole pressure will improve the reasonable productivity and ultimate recovery rate.