Introduction to the well testing analysis software developed by Hefei Chen Gong Technology Co., Ltd

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This post was last edited by Chen Gong Keji-Zheng Lijuan on 2018-11-28 at 11:06. Well testing analysis is a method widely used in the exploration and development of oil and gas fields; it represents essential knowledge and skills for reservoir engineers and related technical personnel. The parameters obtained through well testing analysis play an important role in guiding the exploration and development of oil and gas fields. In the exploration and development of oil and gas fields, we can only measure the bottom hole pressure, production rate, and high-pressure properties of the fluids; however, bottom hole contamination, formation permeability, and reservoir boundaries cannot be measured. It is these unknown parameters that are essential for determining reservoir reserves and formulating development and modification plans. Well testing analysis involves obtaining these unknown parameters through the quantitative interpretation of pressure data. Therefore, well testing analysis is an inverse problem, that is, given the solution of a partial differential equation, the related coefficients in the equation are determined inversely. The technical principles employed for this purpose are: 1. Establish partial differential equations of seepage mechanics based on the seepage characteristics of oil and gas reservoirs. 2. Determine the internal boundary conditions based on the wellbore conditions (such as whether fracturing has been performed, whether it is fully open, whether it is a horizontal well, and whether there is contamination, etc.). 3. Determine the outer boundary conditions of the reservoir based on 3D seismic and other data. 4. Normalize the above equations and boundary conditions to obtain the dimensionless solutions of the equations, and finally create standard graphs. 5. The explanatory parameters are obtained using curve fitting methods, nonlinear regression methods, and straight-line segment analysis methods. 6. The accuracy of the parameters is evaluated through the dimensionless Horner test and pressure history fitting test. Well testing software features powerful well testing analysis models, with over 90,000 different combination solutions available. It offers a wide range of well testing analysis methods that allow for the analysis of pressure data based on specific circumstances. These include: 1) Basic well testing analysis using conventional data, where well testing analysis is carried out by applying the step production superposition method, based on the pressure data obtained and the assumption of known production levels ； 2. Early well testing analysis methods employ small-signal extraction techniques to develop well testing approaches suitable for early-stage well testing analysis, thereby significantly improving the accuracy and success rate of data interpretation ； 3. Well testing analysis of the slug flow pressure and the pressure recovery data during slug flow: based on the energy conservation equation for the wellbore, and by utilizing the coupling relationship between formation flow and wellbore flow, the slug flow pressure as well as the pressures during pressure recovery are calculated for well testing analysis ； 4. Well testing analysis for intermittent production wells: Given that low-permeability oil and gas fields are common in China, many oil wells can only be produced using intermittent methods; therefore, specialized well testing analysis methods have been developed ； 5. The well testing analysis method for production wells, similar to that for intermittent production well testing, employs curve fitting and full pressure history fitting techniques for well testing analysis ； 6. The pressure analysis of wells under intermittent production provides well testing analysis using pressure data from long-term intermittent production, offering a scientific basis for formulating reasonable development plans for such wells ； 7. Interference and pulse well testing analysis: Well-to-well connectivity can be understood through well testing analysis methods that utilize interference pulses ； 8. Well testing analysis method for interlayer interference, a well testing analysis method used for vertical permeability testing. In addition to offering a wide range of methods for well testing analysis, the well testing analysis software also provides powerful data processing and report generation functions, which greatly facilitates its use by users: 1. It is a 100% WINDOWS Microsoft desktop application, with an interface designed in accordance with Microsoft standards; this results in a simple and intuitive interface that is easy for users to operate ； 2. Powerful data processing capabilities: Users can input pressure data from well testing in various ways (such as keyboard entry, reading data files, software calculations, etc.). Various thinning methods are employed for data processing to store pressure history data, as well as functions for data stitching and reprocessing. The quality of pressure data is assessed using pressure derivatives and deviation techniques (such as determining whether any abnormalities occur during well testing, which pressure gauge’s data is most suitable for well testing analysis, whether the pressure data from a particular gauge needs to be corrected, and how to carry out such corrections) ； 3. It features a versatile graphic annotation function that allows users to insert text annotations, graphic annotations, image annotations, and various symbolic annotations into pressure history charts, curve fitting graphs, etc., according to their needs. The type and shape of the annotation frames can be changed, which facilitates the presentation of results ； 4. Powerful report generation capabilities: to meet the various needs of users, reports can be provided in either default or customized formats, including input data, intermediate processing data, and results from well testing analysis and interpretation ； Developed using standard Microsoft Windows software while fully incorporating the advantages of existing domestic and international software, it is available in both Chinese and English versions. The software compiles over 90,000 solutions to the partial differential equations of seepage mechanics, along with a library of more than 90,000 typical curves. Detailed comparative analyses with several major well testing software programs currently in use abroad show that this software has significant advantages. At present, this software has fully replaced imported software and is widely used in onshore and offshore oil and gas fields in China. There are over 4,000 well tests related to pressure testing in the Daqing Oil Field alone, and its versions are continuously updated, earning high praise from users. Some of these achievements won the First Prize for Scientific and Technological Progress of the Chinese Academy of Sciences in 1999, as well as the First Prize for Scientific and Technological Progress of Anhui Province in 2007.