PRODUCTION EVALUATION AND PREDICTION OF HORIZONTAL WELL BASED ON GREY CORRELATION METHOD IN LOW PERMEABILITY GAS RESERVOIR

The evaluation of stable production capacity of horizontal well is the basis of gas field development trend prediction and productivity construction deployment. The gas wells in SDN area are downhole throttling production mode, and the pressure drop rate of some gas wells is lower than that in Sulige central area. How to evaluate the reasonable daily gas production of horizontal wells in the first three years is of great significance to the efficient development of gas field. In this paper, 10 typical horizontal wells are taken as an example, considering geological and engineering factors, the weight of influencing factors of gas well productivity is quantitatively analyzed by using grey correlation method, and the productivity evaluation model is established. The results show that the main factors affecting the productivity of horizontal wells in SDN area are the number of fractured sections, porosity, effective sand body thickness, gas saturation, effective reservoir drilling rate, permeability and horizontal well length. Based on the correlation between the initial production and the comprehensive evaluation factors of productivity, the reasonable daily gas production of horizontal wells in the first three years can be quickly predicted. The average relative error between the predicted results and the actual test production is 7.87%, which proves the reliability and accuracy of the grey correlation method. It provides support for more accurate prediction of horizontal gas well productivity in SDN area.