TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractIn order to meet most test objectives, conventional transient well testing usually requires long flow and shut-in periods. However, the current industry drivers demand short, costeffective, and environmentally friendly test procedures, especially in exploration wells. This is particularly true in deepwater and arctic environments where conventional tests may be prohibitively expensive or logistically not feasible.While various short-term tests, test procedures, and interpretation methods are available for conducting successful short-term tests, clarity is lacking for specific applications of these methods. Some of these tests include surge testing, closed-chamber testing, slug testing, underbalanced perforating and testing, and back-surge perforation cleaning. This paper provides comprehensive evaluation of general closed-chamber tests, including general surge tests, and their comparison with special tests such as, FasTest,™ Impulse™ test, and slug tests. For each of these techniques, the review will examine:• Test design, testing procedure • Theoretical background of each of these techniques • Method of data analysis including comparison based on both theoretical and practical considerations to determine the expected reliability, accuracy, and ease of analysis. A large portion of the paper will be devoted to field examples. Several actual case studies are analyzed using the various techniques, and results are tabulated and presented. The analyses of several of these examples will be presented in significantly more detail to compare techniques available to analyze the well-testing data obtained from surge testing, closed-chamber DST, slug testing of oil wells, underbalanced perforating and testing, and back-surge perforation cleaning.

This work presents a general, straight-line method to estimate the original oil and gas in-place in a reservoir without restrictions on fluid composition. All past efforts are applicable to only restricted ranges of reservoir fluids. Our work supersedes these and is the first to be applicable to the full range of reservoir fluids—including volatile-oils and gas-condensates. Our work is based on the new generalized material-balance equation recently introduced by Walsh.1 The superiority of the new method is illustrated by showing the error incurred by preexisting calculation methods. Guidelines are offered to help identify when preexisting calculation methods must be abandoned and when the new methods featured herein must be employed. The results of our work are summarized in a set of companion papers. Part 1 discusses applications to initially-undersaturated, volumetric reservoirs and Part 2 discusses applications to initially-saturated and non-volumetric reservoirs.

This paper is the second in a two-part series of papers which features practical applications of the generalized material-balance equation. Applications to initially-saturated and non-volumetric reservoirs are discussed in this paper (Part 2); applications to initially-undersaturated, volumetric reservoirs are discussed in Part 1. Graphical methods to estimate the original oil and gas in-place are presented. The graphical methods are general and are applicable to the full range of reservoir fluids of interest. Example calculations are carried out for gas-cap and water-influx reservoirs. These examples, along with those discussed in Part 1, demonstrate the extraordinary power of the generalized material-balance equation.*

Summary Although the mathematical concept of "wavelet transform" was developed in the early part of the 20th century, it did not receive practical application until the 1980s. Wavelet transform is now used in a wide variety of applications in the areas of medicine, biology, and data compression, among others. A significant benefit provided by wavelet transform is its capability to provide two functions: Smoothing of the basic signal. Retention or even enhancement of the details. In data analysis, these characteristics allow the user to recognize hidden signals quickly. In well testing, these capabilities can enhance signals that can be masked by other events or by the data frequency itself. Because the derivative techniques currently used in well testing tend to smooth data and conceal certain events, the use of the wavelet transform to analyze the raw data could prove to be very valuable as a major step in enhancing the techniques of modern data analysis. This paper briefly reviews the application of the wavelet transform methodology to data analysis in general and shows why its application to well-testing data in particular is important. It also provides guidelines for the application of this technology to well testing. Several field examples are provided to demonstrate the application of the wavelet transform to well testing and to show how the qualitative and quantitative uses of the method determine wellbore anomalies, boundary effects, and other well-testing phenomena.

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