ESTIMATION OF INITIAL RESERVOIR PRESSURE BASED ON A «SHORT» PRESSURE BUILD-UP FOR LOW-PERMEABILITY FORMATION

The paper proposes an approach for estimating reservoir pressure in newly drilled zones with low and ultra-low reservoir permeability (1∙10-17 – 1∙10-15 m2). Under such conditions, traditional types of well-testing are not carried out. This approach consists of a short shutdown of the production well for testing to restore bottomhole pressure after its short operation. The method is an analogue of the classical well-testing using the pressure build-up method, but has the advantage of a short well shutdown time. The name of the research method under consideration is a «short» pressure build-up. The proposed method does not require significant research costs and can be applied to all types of well completions, while significantly reducing production losses compared to the traditional method. The paper describes an algorithm for conducting research using this approach. The results of modeling «short» pressure build-up for various well operation scenarios and reservoir parameters are presented. Based on the modeling, a matrix of applicability of the method was constructed, which allows one to estimate the required duration of the study and the relative error of the resulting reservoir pressure. The defining parameter is the ratio of the volume of injected fluid during hydraulic fracturing to the volume of fluid taken during the period of well operation before stopping for testing. The proposed method was tested on field studies, based on the results of which the values of reservoir pressures and their reliability were determined. Materials and methods of the study: flow rate and bottomhole pressure measurements, information from reports on hydraulic fracturing; interpretation of the conducted «short» pressure recovery curves, modeling of the study in the RN-VEGA PC.