Application of the p'D Function to Interference Analysis

Tiab, Djebbar; Kumar, Ashok

doi:10.2118/6053-pa

Cited by 33 publications

(8 citation statements)

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“…Most of these had calculations were described by Maizeret (2013), Lescarboura et al (1975), Tiab and Kumar (1980), and Kamal (1983). The main parameters were first estimated graphically from the diagnostic plots (see the log-log and Cartesian plots in Figure 5 and the summary in Table 3).…”

Section: Well O1mentioning

confidence: 99%

Design and Analysis of Interference Tests – Application to a Seven-Spot Inverted-Pattern Waterflood Pilot in the Wara Formation of the Greater Burgan Field, Kuwait

Gazi

Abdulla

Al-Naqi

et al. 2013

SPE Middle East Oil and Gas Show and Conference

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Interference testing is the oldest but still the most effective way of establishing communication between wells and determining the reservoir transmissibility. However, data can be difficult to interpret and the results can be misleading. Fortunately, simple steps can be performed to validate the data and obtain first estimates of the formation parameters. We demonstrate this methodology for an interference test performed in the Greater Burgan field in Kuwait.A pilot project was started to understand how to successfully inject water in the Wara reservoir. Seven wells were drilled in an area away from the existing wells: one injector at the center of a 250 m-radius hexagon formed by six producers. An interference test was performed between the injector and the producers. The main objective of the study was to evaluate the transmissibility between wells and the permeability anisotropy in the formation. In five of the producers, the target sands were oil bearing, whereas surprisingly, the same sands were water bearing in the sixth well. Consequently, a second objective was added to the study: to check whether the sixth well was in communication with the other wells and to determine the origin of the water.The tests showed that all wells responded to the pressure pulse, including the sixth well, thus refuting the assumption that a fault was isolating it. The fall-off analysis of all the wells highlighted the presence of boundaries, a finding that was consistent with the fluvial depositional environment. Moreover, the analysis showed that the channel was narrowing near the sixth well. Therefore, we could hypothesize that the sixth well had been drilled in a zone with perched water trapped by the channel boundaries. A few weeks after the test, the oil cut started to increase in that well, confirming our hypothesis.The findings from this pilot project proved the efficiency of waterflooding as secondary recovery method and were used to design the pressure maintenance program.

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Section: Well O1mentioning

confidence: 99%

Design and Analysis of Interference Tests – Application to a Seven-Spot Inverted-Pattern Waterflood Pilot in the Wara Formation of the Greater Burgan Field, Kuwait

Gazi

Abdulla

Al-Naqi

et al. 2013

SPE Middle East Oil and Gas Show and Conference

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“…Applications to well test analysis first appeared in the late 1970s: A log-log plot of d⌬p/d(⌬t) vs. ⌬t was suggested as an alternative to straight-line analyses for interference tests (Tiab and Kumar 1980a), tests in fractured wells (Tiab and Puthigai 1988), and tests in reservoirs bounded by two parallel faults (Tiab and Kumar 1980b) and by multiple faults (Tiab and Crichlow 1979). The advantage of using a derivative on the basis of the natural log of elapsed time, d(⌬p)/d(log⌬t), which emphasizes radial flow, was also demonstrated for the description of heterogeneous reservoirs (Perez-Rosales 1978).…”

Section: Log-log Derivative Analysismentioning

confidence: 99%

From Straight Lines to Deconvolution: The Evolution of the State of the Art in Well Test Analysis

Gringarten

2008

SPE Reservoir Evaluation &Amp; Engineering

116

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Well test analysis has been used for many years to assess well condition and obtain reservoir parameters. Early interpretation methods (by use of straight lines or log-log pressure plots) were limited to the estimation of well performance. With the introduction of pressure-derivative analysis in 1983 and the development of complex interpretation models that are able to account for detailed geological features, well test analysis has become a very powerful tool for reservoir characterization. A new milestone has been reached recently with the introduction of deconvolution. Deconvolution is a process that converts pressure data at variable rate into a single drawdown at constant rate, thus making more data available for interpretation than in the original data set, in which only periods at constant rate can be analyzed. Consequently, it is possible to see boundaries in deconvolved data, a considerable advantage compared with conventional analysis, in which boundaries often are not seen and must be inferred. This has a significant impact on the ability to certify reserves.This paper reviews the evolution of well test analysis techniques during the past half century and shows how improvements have come in a series of step changes 20 years apart. Each one has increased the ability to discriminate among potential interpretation models and to verify the consistency of the analysis. This has increased drastically the amount of information that one can extract from well test data and, more importantly, the confidence in that information. IntroductionResults that can be obtained from well testing are a function of the range and the quality of the pressure and rate data available and of the approach used for their analysis. Consequently, at any given time, the extent and quality of an analysis (and therefore what can be expected from well test interpretation) are limited by the stateof-the-art techniques in both data acquisition and analysis. As data improve and better interpretation methods are developed, more and more useful information can be extracted from well test data.Early well test analysis techniques were developed independently from one another and often gave widely different results for the same tests (Ramey 1992). This has had several consequences:• An analysis was never complete because there always was an alternative analysis method that had not been tried.• Interpreters had no basis on which to agree on analysis results.• The general opinion was that well testing was useless given the wide range of possible results.Significant progress was achieved in the late 1970s and early 1980s with the development of an integrated methodology on the basis of signal theory and the subsequent introduction of derivatives. It was found that, although reservoirs are all different in terms of depth, pressure, fluid composition, geology, etc., their behaviors in well tests were made of a few basic components that were always the same. Well test analysis was about finding these components, which could be achieved in a systemati...

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“…In the study by [11] on water flow in aquifers and its influence on water-producing wells, he took the first steps in developing a graphical analysis method that intermediate the field data and the theoretical data for radial regime, which is known as type-curve matching method. Later [2,12,15,18], among others, improved this form of How to cite: Escobar-Macualo, F.H., Rojas-Borrego, E. and Alarcón-Olaya, N.T., Analysis of pressure and pressure derivative interference tests under linear and spherical flow conditions. DYNA, 85(204), pp.…”

Section: Introductionmentioning

confidence: 99%

“…The first application of the pressure derivative in interference tests was done by [18]. This method did not have much impact at first because it made use of the arithmetic derivative and secondly the noise introduced to the pressure data by external sources increased with the derivative and before the 90s there was not many studies with the estimate 45 of the pressure derivative function.…”

Section: Introductionmentioning

confidence: 99%

“…This method did not have much impact at first because it made use of the arithmetic derivative and secondly the noise introduced to the pressure data by external sources increased with the derivative and before the 90s there was not many studies with the estimate 45 of the pressure derivative function. A subsequent analysis was performed by [5], taking as reference the work done by [18] for two-rate testing. [13] presented the analytical models for radial, linear and spherical flow regimes and used type-curve matching and regression analysis for the interpretation of interference tests.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of pressure and pressure derivative interference tests under linear and spherical flow conditions

Escobar

Rojas-Borrego

Alarcón-Olaya

2018

DYNA

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Often, interpretation of interference tests is performed for systems acting under radial flow regimen conditions by means of conventional straight-line method, type-curve matching and TDS technique. For linear and spherical flow cases, the interpretation of interference tests is performed by the conventional analysis and type-curve matching. These procedures do not allow verification of the estimated parameters; therefore, this paper presents the formulation of a more practical, useful and accurate methodology which is achieved based upon the determination of characteristic features found on the pressure and pressure derivative versus time log-log plot with the purpose of developing analytical expressions for the interpretation of interference tests under spherical and linear flow conditions. These equations were successfully verified by their application on synthetic tests.Keywords: interference testing; linear flow; spherical flow; steady state; pseudosteady state.Análisis de presión y derivada de presión en pruebas de interferencia en condiciones de flujos lineal y esférico Resumen Normalmente, la interpretación de las pruebas de interferencia se realiza en sistemas que actúan bajo condiciones de régimen flujo radial utilizando análisis convencional de la línea recta, curvas tipo y técnica TDS. Para los casos de flujos lineal y esférico, la interpretación de pruebas de interferencia se realiza mediante el método convencional y el ajuste con curvas tipo. Estos procedimientos no permiten verificación de los parámetros estimados, y por ello en este trabajo se presenta una formulación de una metodología más práctica, útil y práctica mediante el uso de rasgos características en el gráfico logarítmico de la presión y derivada de presión contra tiempo, que permitan desarrollar expresiones analíticas directas usadas para la caracterización del yacimiento en pruebas interferencia en condiciones de flujos esférico y lineal. Estas ecuaciones se verificaron satisfactoriamente mediante a su aplicación a pruebas sintéticas.Palabras clave: pruebas de interferencia; flujo lineal; flujo esférico; estado estable; estado pseudoestable.

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Application of the p'D Function to Interference Analysis

Cited by 33 publications

References 0 publications

Design and Analysis of Interference Tests – Application to a Seven-Spot Inverted-Pattern Waterflood Pilot in the Wara Formation of the Greater Burgan Field, Kuwait

Design and Analysis of Interference Tests – Application to a Seven-Spot Inverted-Pattern Waterflood Pilot in the Wara Formation of the Greater Burgan Field, Kuwait

From Straight Lines to Deconvolution: The Evolution of the State of the Art in Well Test Analysis

Analysis of pressure and pressure derivative interference tests under linear and spherical flow conditions

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