Research Of Streamline Numerical Well Test Interpretation Method For Alkaline Flooding Reservoirs

Streamline numerical well test interpretation theory is the perfect combination of streamline algorithm and numerical well test interpretation theory. It has realized the best matching of computing speed and precision successfully, thus has a long-term theoretical and practical significance. Streamline numerical well test interpretation theory and method is applied in alkaline flooding reservoirs in a creative way and is well developed in this thesis.This method not only can take several complicated influential factors into consideration , such as, oil-water two-phase flow, production history and multi-well interference, etc, but also can reflect various main mechanisms of enhancing oil displacement (such as, reduction of interfacial tension, mobility control of drive fluid, etc) and physicochemical phenomena(such as, consumption of alkaline, variation of each phase residual saturation and relative permeability, characteristics of polymer solution, etc). Moreover, this thesis also establishes a series of streamline numerical well test interpretation models from water flooding reservoirs to alkaline flooding reservoirs and alkaline/polymer combination flooding reservoirs. The above models all mainly consist of two parts, one is seepage flow mathematical model in the production stage and the other is streamline mathematical model in the testing stage. The former is actually a simplified black oil model, which is used to simulate the whole process of production history, and its solution is suitable to the way of implicit solution method for pressure in grid system and explicit solution method for saturation and component concentration along streamline; the latter is a streamline model composed of all the mathematical equations established for each streamline, which is used to obtained the pressure response features of testing well during the closed time. On the basis of the above theories studying, this thesis simulates several displacement processes and effects under different circumstances of water flooding, alkaline flooding and combination flooding respectively by solving different types of streamline numerical well test interpretation model, and obtains a series of calculation results(such as, saturation distribution, alkaline concentration distribution, polymer concentration distribution, etc), then analyzes the pressure response features of testing well in water flooding , alkaline flooding and combination flooding reservoirs comparatively, furthermore, this thesis also studies on influential characteristics of the pressure response of testing well by the time of alkaline-injection, alkaline-injection slug and alkaline-injection concentration. At last, by making use of multi-parameter well test interpretation technology based on the genetic algorithm, the streamline numerical well test interpretation method which is studied in this thesis is successfully applied in GuanII block in Yangsanmu oilfield. As a result, the thesis obtains not only permeability distribution of well location and other conventional interpreting parameters of testing well, but also the distribution of remaining oil, alkaline concentration and polymer concentration through the establishment of a model consistent with the reservoirs actual situation, and the whole results future identify the practicability and validity of this theory and method.