Analysis of Well Tests From Naturally Fractured Reservoirs by Automated Type-Curve Matching

1995 ◽  
Author(s):  
K. Menekse ◽  
M. Onur ◽  
M. Zeybek
Keyword(s):  
Fractured Reservoirs ◽  
Naturally Fractured Reservoirs ◽  
Curve Matching ◽  
Type Curve ◽  
Naturally Fractured ◽  
Well Tests

Estimation of characteristics of naturally fractured reservoirs by pressure transient analysis

2017 ◽  
Vol 14 (5) ◽  
pp. 368-380
Author(s):  
Mohamed Gamal Rezk ◽  
A.A. Abdelwaly
Keyword(s):  
Fractured Reservoirs ◽  
Direct Synthesis ◽  
Flow Regimes ◽  
Naturally Fractured Reservoirs ◽  
Log Analysis ◽  
Curve Matching ◽  
Type Curve ◽  
Pressure Transient ◽  
Content Type ◽  
Naturally Fractured

Purpose This paper aims to analyze the pressure behavior in dual porosity reservoirs using different techniques in an attempt to correctly characterize reservoir properties. Pressure transient tests in naturally fractured reservoirs often exhibit non-uniform responses. Design/methodology/approach The pressure transient tests in naturally fractured reservoirs were analyzed using conventional semi-log analysis, type curve matching (using commercial software) and Tiab’s direct synthesis (TDS) technique. In addition, the TDS method was applied in case of a naturally fractured formation with a vertical hydraulic fracture. These techniques were applied to a single-layer, naturally fractured reservoir under pseudosteady state matrix flow. By studying the unique characteristics of the different flow regimes appear on the pressure and pressure derivative curves, various reservoir characteristics can be obtained such as permeability, skin factor and fracture properties. Findings For naturally fractured reservoirs, a comparison between the results semi-log analysis, software matching and TDS method is presented. In case of wellbore storage, early time flow regime can be obscured that lead to incomplete semi-log analysis. Furthermore, the type curve matching usually gives a non-uniqueness solution, as it needs all the flow regimes to be observed. However, the direct synthesis method used analytical equation to calculate reservoir and well parameters without type curve matching. For naturally fractured reservoirs with a vertical fracture, the pressure behavior of wells crossed by a uniform flux and infinite conductivity fracture is analyzed using TDS technique. The different flow regimes on the pressure derivative curve were used to calculate the fracture half-length in addition to other reservoir properties. Originality/value The results of different field cases showed that TDS technique offers several advantages compared to semi-log analysis and type curve matching. It can be used even if some flow regimes are not observed. Direct synthesis results are accurate compared to the available core data and the software matching results. It can be used to confirm the software matching results and to give reliable reservoir characteristics when there is lack of data.

Pressure-Transient Behavior of Continuously and Discretely Fractured Reservoirs

2014 ◽  
Vol 17 (01) ◽  
pp. 82-97 ◽  
Author(s):  
Fikri Kuchuk ◽  
Denis Biryukov
Keyword(s):  
Fractured Reservoirs ◽  
Flow Regimes ◽  
Transient Behavior ◽  
Naturally Fractured Reservoirs ◽  
Dual Porosity ◽  
Pressure Transient ◽  
Naturally Fractured ◽  
Dual Porosity Model ◽  
Well Tests ◽  
Porosity Model

Summary Fractures are common features of many well-known reservoirs. Naturally fractured reservoirs contain fractures in igneous, metamorphic, and sedimentary formations. Faults in many naturally fractured carbonate reservoirs often have high-permeability zones, and are connected to many fractures with varying conductivities. Furthermore, in many naturally fractured reservoirs, faults and fractures can be discrete (i.e., not a connected-network fracture system). New semianalytical solutions are used to understand the pressure behavior of naturally fractured reservoirs containing a network of discrete and/or connected (continuous) finite- and infinite-conductivity fractures. We present an extensive literature review of the pressure-transient behavior of fractured reservoirs. First, we show that the Warren and Root (1963) dual-porosity model is a fictitious homogeneous porous medium because it does not contain any fractures. Second, by use of the new solutions, we show that for most naturally fractured reservoirs, the Warren and Root (1963) dual-porosity model is inappropriate and fundamentally incomplete for the interpretation of pressure-transient well tests because it does not capture the behavior of these reservoirs. We examined many field well tests published in the literature. With few exceptions, none of them shows the behavior of the Warren and Root (1963) dual-porosity model. These examples exhibit very diverse pressure behaviors of discretely and continuously fractured reservoirs. Unlike the single derivative shape of the Warren and Root (1963) model, the derivatives of these examples exhibit many different flow regimes depending on fracture distribution and on their intensity and conductivity. We show these flow regimes with our new model for discretely and continuously fractured reservoirs. Most well tests published in the literature do not exhibit the Warren and Root (1963) dual-porosity reservoir-model behavior. If we interpret them by use of this dual-porosity model, then the estimated permeability, skin factor, interporosity flow coefficient (λ), and storativity ratio (ω) will not represent the actual reservoir parameters.

Analysing the limitations of the dual-porosity response during well tests in naturally fractured reservoirs

2018 ◽  
Vol 25 (1) ◽  
pp. 30-49 ◽  
Author(s):  
D. O. Egya ◽  
S. Geiger ◽  
P. W. M. Corbett ◽  
R. March ◽  
K. Bisdom ◽  
...  
Keyword(s):  
Fractured Reservoirs ◽  
Naturally Fractured Reservoirs ◽  
Dual Porosity ◽  
Naturally Fractured ◽  
Well Tests
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