Research On The Method Of Production Performance Prediction In Sour Gas Wells

China is rich in sour gas resources. The development of sour gas reservoirs has become an important way to get natural gas resources. At the initial stage of development, through the performance prediction, production data and its variation with time can be obtained. It provides the basis for formulating reasonable development plan and adjusting working system of gas wells. Sulfur deposition is existed in the development of sour gas reservoir. However, conventional prediction method without considering the sulfur deposition, cannot accurately predict for sour gas reservoir. Therefore, it is necessary to establish a kind of suitable prediction method for sour gas reservoir.Firstly, the mechanism of dissolution and deposition of sulfur were studied. On this basis, the sulfur deposition prediction model and the sulfurous gas well productivity equations are established. This research studied the sulfur migration rules from the mechanics and analyzed the conditions of sulfur deposition and movement.Through theoretical derivation, sour gas wells production performance prediction methods are established from two aspects of material balance and numerical simulation. Eventually, a new software was setup, and did the application for instance. From the study, the main results are as follows:(1) Based on study of the sulfur existence form, it has become clear that elemental sulfur is given priority to physical dissolve and deposition in the reservoir, and quantitative calculation methods of solubility and deposition prediction have been gained.(2) Productivity equations of vertical wells, fracturing wells and horizontal wells have been deduced. The equations consider the conditions of sulfur deposition, start-up pressure gradient and non-Darcy seepage. Depending on the analysis, we obtain the variations of production capacity with sulfur saturation, crack width and horizontal section length.(3) Through the force analysis, calculation formulas of sulfur critical suspension velocity and critical erosion velocity in the reservoir can be got from the article.(4) With material balance principle, material balance equations of different kinds of sour gas reservoirs have been derived. Combined with the productivity equation and the bottom hole pressure formula, set up the prediction method of production performance in sour gas wells.(5) For sour gas reservoir, single phase and gas-solid two phase flows mathematical models have been established, and the solving method of the numerical model is provided in the paper.(6) A software has been developed by VB6.0 which can be applied to well performance prediction in sour gas reservoir. The algorithm of the software is verified and the results are good. Applied software for instance, a certain sour gas well production parameters variations over time are gained, such as output, bottom hole pressure and formation pressure.