Streamline Numerical Welltesting Interpretation Method For Horizontal Wells

With more and more application of horizontal well in the oil-gas field development, the traditional method based on analytic solution cannot accurately explain horizontal welltesting data in high water-cut stage. So it is necessary to develop a new horizontal well numerical welltesting interpretation method that can exactly describe the real reservoir. By introducing streamline numerical welltesting technology, horizontal wells streamline numerical welltesting interpretation method is developed, which can consider many complex factors, such as production history,heterogeneity,well pattern and so on. Firstly, horizontal streamline numerical welltesting model is established, which includes two models, one for the production period, and the other for testing period. The former is the simplified black oil model and the other is streamline model which is composed of all equations for every streamline around the testing well. The streamline model can take formation heterogeneity and fluid properties into consideration. Secondly, horizontal well streamline numerical solving method is formed and the streamline method transforms the three dimensional seepage problem of horizontal well into one dimensional problem, which has high computing speed and good stability. Thirdly, the pressure response in different conditions is studied including skin factor, well storage, reservoir relative thickness, the position of the horizontal, vertical and horizontal permeability ratio, the reservoir heterogeneity, mixed boundary, oil-water viscosity ratio and different well pattern etc.Lastly, double-population genetic algorithm is used to horizontal streamline numerical well testing interpretation and a software is developed, which can interpret a lot of parameters such as wellbore storage, skin factor, the distribution of permeability and so on. And the software is successfully applied to the filed and the interpretation result is in accordance with the fact. Horizontal well streamline numerical welltesting method can consider more factors and can describe the reservoir more accurately, which is great worth in application.