Weatherford has a wide range of experience in well test analysis, related to the development of the company's software development, consulting, and training services.
Weatherford has the foremost experts in well test analysis in the industry, with many years of practical experience in the analysis and interpretation of well tests. Our consultancy expertise has been enhanced by the parallel development of the PanSystem® software well test analysis package, which is the world's market leader, and by giving many training courses all over the world. In addition, Weatherford engineers have substantial practical experience in the acquisition of well test data, having worked for some of the leading data acquisition companies throughout the world and supervised many tests. In-house expertise in the associated areas of production log analysis, PVT studies, core analysis, and geomechanics allows a depth of understanding in well performance to an unparalleled level. Some of the areas in which Weatherford has a unique level of expertise include:
The design and supervision of multi-layered well tests are crucial to the understanding of complex layered reservoirs. Many sedimentary reservoirs are the result of paleoenvironments of deposition which result in vertically limited bodies separated by lower permeability horizons. The determination and analysis of connectivity between each layer is paramount to understanding reservoir production. Our engineers have a proven expertise in this field and have assisted in the development of Weatherford's PanSystem software to aid the interpretation of production log tool data.
Production Log and Analysis Interface
Decisions on workovers and production optimization are invariably based on the analysis of production logs and well tests. Combining many years of practical experience gained in production log acquisition and interpretation, and expertise using Weatherford's WellFlo® software, a production optimization software package, our engineers are well placed to analyze even the most difficult problems. In addition, PLOG, a production log analysis software package, is available for in-house use.
The methodology for prediction of gas condensate deliverability using steady state, two phase pseudo-pressures and PVT is based on Equations of State (EoS) recently developed by Weatherford engineers. These analyses allow gas condensate well tests to be interpreted, taking into account liquid dropout, over a wide range of pressures and temperatures, therefore better predicting fluid behavior and allowing production modeling.
Reservoirs which are composed of a number of blocks separated by partially communicating barriers are a very important feature of reservoir descriptions, especially in faulted traps. Weatherford pioneered the identification of compartmentalized reservoirs using well tests and material balance calculations and have a proven track record in this area accumulated while successfully completing a number of volumetric studies.
Complex Geological Environments
The interaction between core analysis and well test analysis allows Weatherford to effectively describe complex reservoirs. Vertical (fault planes) and horizontal (shales) barriers often combine to produce a geologically intricate body which cannot be satisfactorily analyzed using conventional well test techniques. The integration of validated laboratory core data permits Weatherford engineers to confirm possible interpretations and establish suitable reservoir models and optimum production profiles.
The importance of effective flow length and formation thickness is recognized in horizontal well test analysis and has been incorporated into PanSystem software. The determination of both permeability and skin has allowed the precise identification of horizontal well performance based on compartmentalized reservoirs and sweet spots, available in PanSystem and WellFlo software: both of which are frequently used by our engineers while determining horizontal DSTs.
Numerous well tests have been investigated during the PanSystem software development program and as a result of our software support services. In addition, Weatherford engineers have presented special horizontal well test analysis seminars worldwide.
Extended Well Tests
The evaluation of variable rate production well test data is a much neglected area of analysis. Weatherford has developed new methods which allow real extended drawdown tests to be adequately interpreted.
Injection Well Tests
The effects of thermal fracturing and variable wellbore storage make the interpretation of injection well tests difficult. Special techniques have been developed to allow the proper understanding of these tests and they have been extended into slug test analysis and the interpretation of coal bed methane projects. The latter is potentially an important area of hydrocarbon exploration and production and offers considerable scope for the integrated skills within Weatherford.