Application of Leaky Aquifer Type Curves for Coalbed Methane Characterization

2002 ◽  
Author(s):  
D.O. Cox ◽  
P.R. Onsager
Keyword(s):  
Coalbed Methane ◽  
Type Curves ◽  
Leaky Aquifer ◽  
Aquifer Type

scholarly journals Fracturing curve and its corresponding gas productivity of coalbed methane wells in the Zhengzhuang block, southern Qinshui Basin, North China

2020 ◽  
Vol 38 (5) ◽  
pp. 1387-1408
Author(s):  
Yang Chen ◽  
Dameng Liu ◽  
Yidong Cai ◽  
Jingjie Yao
Keyword(s):  
Hydraulic Fracturing ◽  
Coalbed Methane ◽  
Continuous Production ◽  
Fracture Morphology ◽  
Geological Structure ◽  
In Situ Stress ◽  
Gas Production ◽  
Type Curves ◽  
Stable Type

Hydraulic fracturing has been widely used in low permeability coalbed methane reservoirs to enhance gas production. To better evaluate the hydraulic fracturing curve and its effect on gas productivity, geological and engineering data of 265 development coalbed methane wells and 14 appraisal coalbed methane wells in the Zhengzhuang block were investigated. Based on the regional geologic research and statistical analysis, the microseismic monitoring results, in-situ stress parameters, and gas productivity were synthetically evaluated. The results show that hydraulic fracturing curves can be divided into four types (descending type, stable type, wavy type, and ascending type) according to the fracturing pressure and fracture morphology, and the distributions of different type curves have direct relationship with geological structure. The vertical in-situ stress is greater than the closure stress in the Zhengzhuang block, but there is anomaly in the aggregation areas of the wavy and ascending fracturing curves, which is the main reason for the development of multi-directional propagated fractures. The fracture azimuth is consistent with the regional maximum principle in-situ stress direction (NE–NEE direction). Furthermore, the 265 fracturing curves indicate that the coalbed methane wells owned descending, and stable-type fracturing curves possibly have better fracturing effect considering the propagation pressure gradient (FP) and instantaneous shut-in pressure (PISI). Two fracturing-productivity patterns are summarized according to 61 continuous production wells with different fracturing type and their plane distribution, which indicates that the fracturing effect of different fracturing curve follows the pattern: descending type > stable type > wavy type > ascending type.

Type Curves for Production Prediction and Evaluation of Coalbed Methane Reservoirs

2005 ◽  
Author(s):  
K. Aminian ◽  
S. Ameri ◽  
A.B. Bhavsar ◽  
S. Lakshminarayanan
Keyword(s):  
Coalbed Methane ◽  
Type Curves ◽  
Production Prediction

scholarly journals Production decline type curves analysis of a finite conductivity fractured well in coalbed methane reservoirs

Open Physics ◽  
2017 ◽  
Vol 15 (1) ◽  
pp. 143-153 ◽  
Author(s):  
Mingqiang Wei ◽  
Ming Wen ◽  
Yonggang Duan ◽  
Quantang Fang ◽  
Keyi Ren
Keyword(s):  
Flow Regime ◽  
Coalbed Methane ◽  
Radial Flow ◽  
Production Model ◽  
Finite Conductivity ◽  
Type Curves ◽  
State Diffusion ◽  
Diffusion And Convection ◽  
Fractured Well ◽  
Advanced Production

AbstractProduction decline type curves analysis is one of the robust methods used to analyze transport flow behaviors and to evaluate reservoir properties, original gas in place, etc. Although advanced production decline analysis methods for several well types in conventional reservoirs are widely used, there are few models of production decline type curves for a fractured well in coalbed methane (CBM) reservoirs. In this work, a novel pseudo state diffusion and convection model is firstly developed to describe CBM transport in matrix systems. Subsequently, based on the Langmuir adsorption isotherm, pseudo state diffusion and convection in matrix systems and Darcy flow in cleat systems, the production model of a CBM well with a finite conductivity fracture is derived and solved by Laplace transform. Advanced production decline type curves of a fractured well in CBM reservoirs are plotted through the Stehfest numerical inversion algorithm and computer programming. Six flow regimes, including linear flow regime, early radial flow in cleat systems, interporosity flow regime, late pseudo radial flow regime, transient regime and boundary dominated flow regime, are recognized. Finally, the effect of relevant parameters, including the storage coefficient of gas in cleat systems, the transfer coefficient from a matrix system to the cleat system, the modified coefficient of permeability, dimensionless fracture conductivity and dimensionless reservoir drainage radius, are analyzed on type curves. This paper does not only enrich the production decline type curves model of CBM reservoirs, but also expands our understanding of fractured well transport behaviors in CBM reservoirs and guides to analyze the well's production performance.

Type Curves for Coalbed Methane Production Prediction

2004 ◽  
Author(s):  
K. Aminian ◽  
S. Ameri ◽  
A. Bhavsar ◽  
M. Sanchez ◽  
A. Garcia
Keyword(s):  
Methane Production ◽  
Coalbed Methane ◽  
Type Curves ◽  
Coalbed Methane Production ◽  
Production Prediction

scholarly journals Solution and type curves for the seepage model of the water-bearing coalbed with leakage recharge

2017 ◽  
Vol 21 (1) ◽  
pp. 17 ◽  
Author(s):  
Wangang Chen ◽  
Yu Yang ◽  
Hansen Sun ◽  
Chengwei Zhang ◽  
Qin Wen ◽  
...  
Keyword(s):  
Coalbed Methane ◽  
Radial Flow ◽  
Curve Matching ◽  
Pressure Derivative ◽  
Type Curve ◽  
Type Curves ◽  
Reservoir Permeability ◽  
Leakage Coefficient ◽  
Seepage Theory ◽  
Seepage Model

To analyze the effects of the leakage recharge of the aquifer on the initial dewatering of coalbed methane wells, the mathematical seepage model of water in the coalbed considering the aquifer leakage was established by using the leakage coefficient according to the unsteady seepage theory. The model was solved after Laplace transform and the Stehfest numerical reverse inversion was used to obtain the solution in right space. Then, the log-log type curves of pressure and pressure derivative were created with new combinations of parameters. Based on the natural seepage mechanism, the influence of aquifer leakage on curve shape was judged. It is found that the radial flow ends earlier as the leakage coefficient increases. Moreover, it was proposed to obtain reservoir permeability, skin factor, and leakage coefficient by using type curve matching. The type curves are useful for quantitatively evaluating the level of leakage, thereby guiding the adjustment of the following production system for CBM wells. Curvas de solución y tipo para el modelo de filtración de capas carboníferas acuíferas con recarga de fugasResumenEste estudio estableció el modelo matemático de filtración de agua en una capa carbonífera al estimar la salida acuífera con el uso del coeficiente de fuga, de acuerdo con la teoría de filtración inestable, para analizar los efectos en la recarga de pérdida de fluidos de un acuífero en el drenado inicial para pozos de gas metano.  El modelo se resolvió tras usar la transformación Laplace y la inversión numérica Stehfest para encontrar la respuesta en el lugar indicado. Luego, se creó la representación algorítmica de la presión y la presión derivativa con nuevas combinaciones de parámetros. Se evaluó la influencia de la pérdida de fluido del acuífero en la forma de la curva con base al mecanismo físico de filtración. Se estableció que el flujo radial finaliza antes de que el coeficiente de pérdida de fluido se incremente. Además, se propone el uso de la curva tipo correspondiente para obtener la permeabilidad del reservorio, el factor de daño y el coeficiente de pérdida de fluido. Las curvas tipo son útiles para evaluar cuantitativamente el nivel de la pérdida de fluido, y de esta manera guiar el ajuste de un sistema de producción consecuente para pozos de gas metano de carbón.

scholarly journals Numerical Simulation of Unsteady-State Flow in Dual Porous Coalbed Methane Horizontal Wells with Complex Boundary Conditions

2015 ◽  
Vol 2015 ◽  
pp. 1-11
Author(s):  
Cheng-yong Li ◽  
Jun Zhou ◽  
Xiang-yi Yi ◽  
Yi Luo ◽  
Ping-zhi Gong
Keyword(s):  
Boundary Conditions ◽  
Coalbed Methane ◽  
Gas Flow ◽  
Flow Characteristics ◽  
Horizontal Wells ◽  
Basic Solution ◽  
Pressure Derivative ◽  
Type Curves ◽  
Complex Boundary ◽  
Lord Kelvin

The bottom-hole pressure response which can reflect the gas flow characteristics is important to study. A mathematical model for description of gas from porous coalbed methane (CBM) reservoirs with complex boundary conditions flowing into horizontal wells has been developed. Meanwhile, basic solution of boundary elements has been acquired by combination of Lord Kelvin point source solution, the integral of Bessel function, and Poisson superimpose formula for CBM horizontal wells with complex boundary conditions. Using this model, type curves of dimensionless pressure and pressure derivative are obtained, and flow characteristics of horizontal wells in complex boundary reservoirs and relevant factors are accordingly analyzed.

Production Data Analysis of Coalbed-Methane Wells

2008 ◽  
Vol 11 (02) ◽  
pp. 311-325 ◽  
Author(s):  
Christopher R. Clarkson ◽  
Colin L. Jordan ◽  
Roger R. Gierhart ◽  
John P. Seidle
Keyword(s):  
Data Analysis ◽  
Coalbed Methane ◽  
Single Phase ◽  
Material Balance ◽  
Pressure Data ◽  
Single Phase Flow ◽  
Two Phase ◽  
Type Curves ◽  
Production Type ◽  
Permeability Changes

Summary Recent advances in production data analysis (PDA) techniques have greatly assisted engineers in extracting meaningful reservoir and stimulation information from well-production and flowing-pressure data. Application of these techniques to coalbed-methane (CBM) reservoirs requires the unique coal storage and transport properties to be accounted for. In recent work, the authors [ex. Clarkson et al. (2007a) and Jordan et al. (2006)] and others [ex. Gerami et al. (2007)] have demonstrated how new techniques such as the flowing material balance (FMB) and production type curves may be adapted to account for CBM storage mechanisms (i.e., adsorption), but, to date, the focus has been on relatively simple CBM reservoir behavior such as single-phase (gas) reservoirs with static effective permeability. The major contribution of the current work is the adaptation of modern PDA techniques (by use of modified material balance time/pseudotime and pseudopressure definitions) to analyze producing wells completed in CBM reservoirs exhibiting several possible flow characteristics: single-phase flow of gas in dry CBM reservoirs, single-phase flow of water (in undersaturated reservoirs), and two-phase (gas and water) flow (in saturated reservoirs). The latter reservoir type commonly exhibits effective permeability changes during depletion (because of relative and/or absolute permeability changes) and changing gas composition caused by relative adsorption effects, both of which have been accounted for in the current work. Specifically, the FMB technique is modified to include several complex CBM reservoir characteristics, and production type curves are applied to some scenarios. Although dry-CBM-well analysis was covered previously [ex. Clarkson et al. (2007a)], we will also discuss FMB development in these reservoirs for completeness. Several synthetic and field examples are given to demonstrate how FMB, type-curve analysis, and analytical simulation can be used in parallel to provide a particularly useful data-analysis toolset and workflow. These techniques were used successfully to extract quantitative reservoir information from single- and two-phase CBM-simulated and field-production pressure data. The PDA techniques developed for two-phase CBM require further evaluation, however.

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