Transient Pressure Analysis of Wells Intercepted by Partially Penetrating Finite Conductivity Hydraulic Fractures

Most current pressure transient analysis techniques of hydraulically fractured wells are based on the fully penetrating assumption, which assumes equal thickness of hydraulic fracture and the formation. However, field application show that the fractures thickness can be shorter than the thickness of formation, which leads to vertical flow into the fracture. Thus applying the thickness equality assumption of current well test models to a partial penetrating fracture may give contradictory result. Further, there are very few studies concerning pressure transient analysis of partial penetrated wells. So it is important to develop analysis model and procedure to this type of fracture. In this paper, we presented an analytical model for partially penetrating hydraulic fracture in isotropic systems, along with the assumption that fracture is finite conductive. This model is then applied in the analysis of field production data, which verified validity of this new model.

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An approximation of behind-casing hydraulic conductivity between layers from transient pressure analysis

DYNA ◽

10.15446/dyna.v86n210.76739 ◽

2019 ◽

Vol 86 (210) ◽

pp. 108-114

Author(s):

Freddy Humberto Escobar ◽

Angela María Palomino ◽

Alfredo Ghisays Ruiz

Keyword(s):

Hydraulic Conductivity ◽

Transient Analysis ◽

Test Interpretation ◽

Well Test ◽

Transient Pressure ◽

Pressure Transient Analysis ◽

Pressure Transient ◽

Transient Pressure Analysis ◽

Pressure Analysis

Flow behind the casing has normally been identified and quantified using production logging tools. Very few applications of pressure transient analysis, which is much cheaper, have been devoted to determining compromised cemented zones. In this work, a methodology for a well test interpretation for determining conductivity behind the casing is developed. It provided good results with synthetic examples.

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Pressure Transient Analysis for Fracture-Cavity Carbonate Reservoirs with Large Scale Fractures-Caves in Series Connection

Journal of Energy Resources Technology ◽

10.1115/1.4051739 ◽

2021 ◽

pp. 1-20

Author(s):

Cuiqiao Xing ◽

Hongjun Yin ◽

Hongfei Yuan ◽

Jing Fu ◽

Guohan Xu

Keyword(s):

Transient Analysis ◽

Carbonate Reservoir ◽

Carbonate Reservoirs ◽

Test Model ◽

Well Test ◽

Analysis Model ◽

Pressure Transient Analysis ◽

Linear Flow ◽

Pressure Transient ◽

Well Test Model

Abstract Fractured vuggy carbonate reservoirs are highly heterogeneous and non-continuous, and contains not only erosion pores and fractures but also the vugs. Unfortunately, the current well test model cannot be used to analyze fractured-vuggy carbonate reservoirs, due to the limitations of actual geological characteristics. To solve the above-mentioned problem, a pressure transient analysis model for fracture-cavity carbonate reservoir with radial composite reservoir that the series multi-sacle fractures and caves exist and dual-porosity medium (fracture and erosion pore) is established in this paper, which is suitable for fractured vuggy reservoirs. Laplace transformation is used to alter and solve the mathematical model. The main fractures' linear flow and the radial flow of caves drainage area are solved by coupling. The pressure-transient curves of the bottomhole have been obtained with the numerical inversion algorithms. The typical curves for well test model which has been established are drawn, and flow periods are analyzed. The sensitivity analysis for different parameters is analyzed. The variation characteristic of typical curves is by the theoretical analysis. With the increasing of fracture length, the time of linear flow is increased. While the cave radius is the bigger, the convex and concave of the curve is the larger. As a field example, actual test data is analyzed by the established model. An efficient well test analysis model is developed, and it can be used to interpret the actual pressure data for fracture-cavity carbonate reservoirs.

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Pressure-Transient Analysis of a Well With an Inclined Hydraulic Fracture

SPE Reservoir Evaluation & Engineering ◽

10.2118/120540-pa ◽

2010 ◽

Vol 13 (06) ◽

pp. 845-860 ◽

Cited By ~ 9

Author(s):

Anh V. Dinh ◽

Djebbar Tiab

Keyword(s):

Flow Regime ◽

Hydraulic Fracture ◽

Transient Analysis ◽

Hydraulic Fractures ◽

Pressure Derivative ◽

Pressure Transient Analysis ◽

Pressure Transient ◽

Fracture Models ◽

Infinite Conductivity ◽

Conductivity Models

Summary Hydraulic fracturing is an important well-stimulation technique that has been widely used in the oil and gas industry. Most of the pressure-transient-analysis techniques to analyze pressure responses of fractured wells are based on the assumption that the fracture is either vertical or horizontal. However, a hydraulic fracture could be inclined with a nonzero angle with respect to the vertical direction. Field studies have shown that most hydraulic fractures are not perfectly vertical. Thus, for an inclined hydraulic fracture, the vertical-orientation assumption may lead to erroneous results in welltest analysis, especially when the inclination angle is significant. However, there are very few studies concerning pressure-transient analysis of inclined hydraulic fractures, and there is no applicable well-test-analysis procedure available for inclined fractures. The purpose of this study is to develop a technique, on the basis of the pressure-derivative concept, for interpreting pressuretransient tests in wells with an inclined hydraulic fracture. Detailed analysis of unsteady-state pressure behavior of a fully penetrating inclined fracture in an infinite-slab reservoir was provided. Both uniform-flux and infinite-conductivity models were considered. The study has shown that inclined-fracture pressure data exhibit flow regimes similar to those for vertical fractures. Those flow regimes are linear and pseudoradial flow for both uniform-flux and infinite-conductivity models. However, for the infinite-conductivity model, a biradial- (or elliptical) flow regime is also observed. In the case of a high formation-thickness/fracture-half-length ratio and high angle of inclination, both uniform-flux and infiniteconductivity inclined-fracture models exhibit an additional flow regime, called early radial (ER) flow in this paper. This ER-flow regime for an inclined hydraulic fracture has not been mentioned in the literature before. A type-curve-matching technique was developed in this study using both pressure and pressure-derivative curves. This typecurve-matching procedure can be used to obtain the following parameters: fracture half-length, inclination angle, formation permeability, and the pseudoskin factor. The results should be verified with other pressure plots such as the semilog plot of vs. t and the Δp-vs.-t1/2 plot. A set of type curves with associated data was also provided for uniform-flux and infinite-conductivity inclined- fracture models. Detailed explanations, tables, figures, and a numerical example are included in this paper.

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A Semianalytical Model for Pressure-Transient Analysis of Fractured Wells in Unconventional Plays With Arbitrarily Distributed Discrete Fractures

SPE Journal ◽

10.2118/187290-pa ◽

2018 ◽

Vol 23 (06) ◽

pp. 2041-2059 ◽

Cited By ~ 20

Author(s):

Zhiming Chen ◽

Xinwei Liao ◽

Kamy Sepehrnoori ◽

Wei Yu

Keyword(s):

Fluid Flow ◽

Hydraulic Fracture ◽

Transient Analysis ◽

Fractured Reservoirs ◽

Naturally Fractured Reservoirs ◽

Hydraulic Fractures ◽

Natural Fractures ◽

Fracture Networks ◽

Pressure Transient Analysis ◽

Pressure Transient

Summary In this paper, we present an efficient semianalytical model for pressure-transient analysis in fractured wells by considering arbitrarily distributed fracture networks. The semianalytical model included three domains: matrix, hydraulic-fracture networks, and discrete natural fractures. Using the line-source function, we developed the diffusivity equation for fluid flow in matrix. By applying the vertex-analysis technique, we eliminated the flow interplay at fracture intersections and established the diffusivity equations for fluid flow in hydraulic-fracture networks and isolated natural fractures. The pressure-transient solution of these diffusivity equations was obtained using Laplace transforms and the Stehfest numerical inversion. Results showed that with the discrete natural fractures, a “V-shaped” pressure derivative (the classical dual-porosity feature of naturally fractured reservoirs) emerged. With the hydraulic-fracture networks, the reservoir system would exhibit pressure behaviors such as “pseudoboundary-dominated flow,” “fracture-interference flow,” and “fluid-feed flow.” All these pressure characteristics were dependent on the properties and geometries of natural/hydraulic fractures. In addition, through synthetic field application, we found that different (natural/hydraulic) fracture distributions and geometries had distinct behaviors of pressure derivatives, which may provide an effective tool to identify the properties of randomly distributed natural fractures as well as complex hydraulic fractures in unconventional plays.

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