An Investigation of Pressure and Production Data Using Decline and Type Curve Analysis

2017 ◽  
Author(s):  
Arifur Rahman ◽  
Fatema Akter Happy ◽  
Mahbub Alam Hira ◽  
M. Enamul Hossain
Keyword(s):  
History Matching ◽  
Fractured Reservoirs ◽  
Curve Analysis ◽  
The Other ◽  
Production Data ◽  
Type Curve ◽  
Type Curves ◽  
Decline Curve Analysis ◽  
Decline Curve ◽  
Analysis Technique

Decline curve analysis is one of the most widely used production data analysis technique for forecasting whilst type curve analysis is a graphical representation technique for history matching and forecasting. The combination of both methods can estimate the reserves and the well/reservoir parameters simultaneously. The purpose of this study is to construct the new production decline curves to analyze the pressure and production data. These curves are constructed by combining decline curve and a type curve analysis technique that can estimate the existing reserves and determine the other well/reservoir parameters for gas wells. The accuracy of these parameter estimations depends on the quality and type of the pressure and production data available. This study illustrates the conventional decline curve that can be used to analyze the gas well performance data with type curves based on pseudo time function. On the other hand, log-log plots are used as a diagnostic tool to identify the appropriate reservoir model and analogous data trend. Pressure derivative and type curves are used to construct a radial model of the reservoir. In addition, Blasingame and Fetkovich type curves analysis are also presented in a convenient way. The decline curve analysis shows steady state production for a long time, then a decline is observed which indicates a boundary dominated flow. The Blasingame type curve matching points is going downward, which indicate the influence of another nearby well. The reservoir parameters that are obtained by using the decline curve and type curves analysis show a similar trend and close match for different approaches. These observations closely match results of different analysis. This analysis improves the likelihood of the results being satisfactory and reliable, though it changes with time until the end of the production period. This analysis technique can be extended to other type of well/reservoir system, including horizontal wells and fractured reservoirs.

Unified Decline Type-Curve Analysis for Natural Gas Wells in Boundary-Dominated Flow

SPE Journal ◽  
2012 ◽  
Vol 18 (01) ◽  
pp. 97-113 ◽  
Author(s):  
Ayala H Luis F. ◽  
Peng Ye
Keyword(s):  
Natural Gas ◽  
Constant Pressure ◽  
Curve Analysis ◽  
Production Data ◽  
Gas Wells ◽  
Production Potential ◽  
Type Curve ◽  
Type Curves ◽  
Decline Curve Analysis ◽  
Decline Curve

Summary Rate-time decline-curve analysis is the technique most extensively used by engineers in the evaluation of well performance, production forecasting, and prediction of original fluids in place. Results from this analysis have key implications for economic decisions surrounding asset acquisition and investment planning in hydrocarbon production. State-of-the-art natural gas decline-curve analysis heavily relies on the use of liquid (oil) type curves combined with the concepts of pseudopressure and pseudotime and/or empirical curve fitting of rate-time production data using the Arps hyperbolic decline model. In this study, we present the analytical decline equation that models production from gas wells producing at constant pressure under boundary-dominated flow (BDF) which neither employs empirical concepts from Arps decline models nor necessitates explicit calculations of pseudofunctions. New-generation analytical decline equations for BDF are presented for gas wells producing at (1) full production potential under true wide-open decline and (2) partial production potential under less than wide-open decline. The proposed analytical model enables the generation of type-curves for the analysis of natural gas reservoirs producing at constant pressure and under BDF for both full and partial production potential. A universal, single-line gas type curve is shown to be straightforwardly derived for any gas well producing at its full potential under radial BDF. The resulting type curves can be used to forecast boundary-dominated performance and predict original gas in place without (1) iterative procedures, (2) prior knowledge of reservoir storage properties or geological data, and (3) pseudopressure or pseudotime transformations of production data obtained in the field.

Decline Curve Analysis of Fractured Horizontal Wells Through Segmented Fracture Model

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Jiazheng Qin ◽  
Shiqing Cheng ◽  
Youwei He ◽  
Yang Wang ◽  
Dong Feng ◽  
...  
Keyword(s):  
Production Rate ◽  
History Matching ◽  
Curve Analysis ◽  
Production Performance ◽  
Fracture Model ◽  
Total Production ◽  
Type Curves ◽  
Decline Curve Analysis ◽  
Decline Curve ◽  
Compound Type

Nowadays, production performance evaluation of a multifractured horizontal well (MFHW) has attracted great attention. This paper presents a mathematical model of an MFHW with considering segmented fracture (SF) for better evaluation of fracture and reservoir properties. Each SF consists of two parts: fracture segment far from wellbore (FSFW) and fracture segment near to wellbore (FSNW) in segmented fracture model (SFM), which is different from fractures consists of only one segment in common fracture model (CFM). Employing the source function and Green's function, Newman's product method, Duhamel principle, Stehfest inversion algorithm, and Laplace transform, production solution of an MFHW can be obtained using SFM. Total production rate is mostly contributed from FSNW rather than FSFW in many cases; ignoring this phenomenon may lead to obvious erroneous in parameter interpretation. Thus, clear distinctions can be found between CFM and SFM on the compound type curves. By using decline curve analysis (DCA), the influences of sensitive parameters (e.g., dimensionless half-length, dimensionless production rate, conductivity, and distance between SF) on compound type curves are analyzed. The results of sensitivity analysis are benefit of parameter estimation during history matching.

Analyzing Well Production Data Using Combined Type Curve and Decline Curve Analysis Concepts

1998 ◽  
Author(s):  
Ram G. Agarwal ◽  
David C. Gardner ◽  
Stanley W. Kleinsteiber ◽  
Del D. Fussell
Keyword(s):  
Curve Analysis ◽  
Production Data ◽  
Type Curve ◽  
Well Production ◽  
Decline Curve Analysis ◽  
Decline Curve

Integral Type Curves for Advanced Decline Curve Analysis

1992 ◽  
Author(s):  
J.P. Spivey ◽  
J.M. Gatens ◽  
M.E. Semmelbeck ◽  
W.J. Lee
Keyword(s):  
Curve Analysis ◽  
Integral Type ◽  
Type Curves ◽  
Decline Curve Analysis ◽  
Decline Curve

Quantification of Uncertainty in Reserves Estimation From Decline Curve Analysis of Production Data for Unconventional Reservoirs

2007 ◽  
Author(s):  
Yueming Cheng ◽  
W. John Lee ◽  
Duane A. McVay
Keyword(s):  
Oil And Gas ◽  
Curve Analysis ◽  
Production Data ◽  
Data Sets ◽  
Gas Wells ◽  
Advanced Technique ◽  
Unconventional Resources ◽  
Decline Curve Analysis ◽  
Decline Curve ◽  
Reserve Estimates

Decline curve analysis is the most commonly used technique to estimate reserves from historical production data for evaluation of unconventional resources. Quantifying uncertainty of reserve estimates is an important issue in decline curve analysis, particularly for unconventional resources since forecasting future performance is particularly difficult in analysis of unconventional oil or gas wells. Probabilistic approaches are sometimes used to provide a distribution of reserve estimates with three confidence levels (P10, P50 and P90) and a corresponding 80% confidence interval to quantify uncertainties. Our investigation indicates that uncertainty is commonly underestimated in practice when using traditional statistical analyses. The challenge in probabilistic reserves estimation is not only how to appropriately characterize probabilistic properties of complex production data sets, but also how to determine and then improve the reliability of the uncertainty quantifications. In this paper, we present an advanced technique for probabilistic quantification of reserve estimates using decline curve analysis. We examine the reliability of uncertainty quantification of reserve estimates by analyzing actual oil and gas wells that have produced to near-abandonment conditions, and also show how uncertainty in reserves estimates changes with time as more data become available. We demonstrate that our method provides more reliable probabilistic reserves estimation than other methods proposed in the literature. These results have important impacts on economic risk analysis and on reservoir management.

A Decline Curve Analysis Model Based on Fluid Flow Mechanisms

2005 ◽  
Vol 8 (03) ◽  
pp. 197-204 ◽  
Author(s):  
Kewen Li ◽  
Roland N. Horne
Keyword(s):  
Fluid Flow ◽  
Linear Relationship ◽  
Relative Permeability ◽  
Oil Recovery ◽  
Single Phase ◽  
Oil Production ◽  
Curve Analysis ◽  
Production Data ◽  
Decline Curve Analysis ◽  
Decline Curve

Summary Decline-curve-analysis models are used frequently but still have many limitations. Approaches of decline-curve analysis used for naturally fractured reservoirs developed by waterflooding have been few. To this end, a decline-analysis model derived on the basis of fluid-flow mechanisms was proposed and used to analyze the oil-production data from naturally fractured reservoirs developed by waterflooding. Relative permeability and capillary pressure were included in this model. The model reveals a linear relationship between the oil-production rate and the reciprocal of the oil recovery or the accumulated oil production. We applied the model to the oil-production data from different types of reservoirs and found a linear relationship between the production rate and the reciprocal of the oil recovery as foreseen by the model, especially at the late period of production. The values of maximum oil recovery for the example reservoirs were evaluated with the parameters determined from the linear relationship. An analytical oil-recovery model was also proposed. The results showed that the analytical model could match the oil-production data satisfactorily. We also demonstrated that the frequently used nonlinear type curves could be transformed to linear relationships in a log-log plot. This may facilitate the production-decline analysis. Finally, the analytical model was compared with conventional models. Introduction Estimating reserves and predicting production in reservoirs has been a challenge for many years. Many methods have been developed in the last several decades. One frequently used technique is the decline-curve-analysis approach. There have been a great number of papers on this subject. Most of the existing decline-curve-analysis techniques are based on the empirical Arps equations: exponential, hyperbolic, and harmonic. It is difficult to foresee which equation the reservoir will follow. On the other hand, each approach has some disadvantages. For example, the exponential decline curve tends to underestimate reserves and production rates; the harmonic decline curve has a tendency to overpredict the reservoir performance. In some cases, production-decline data do not follow any model but cross over the entire set of curves. Fetkovich combined the transient rate and the pseudosteady-state decline curves in a single graph. He also related the empirical equations of Arps to the single-phase-flow solutions and attempted to provide a theoretical basis for the Arps equations. This was realized by developing the connection between the material balance and the flow-rate equations on the basis of his previous papers. Many derivations were based on the assumption of single-phase oil flow in closed-boundary systems. These solutions were suitable only for undersaturated(single-phase) oil flow. However, many oil fields are developed by waterflooding. Therefore, two-phase fluid flow (rather than single-phase flow)occurs. In this case, Lefkovits and Matthews derived the exponential decline form for gravity-drainage reservoirs with a free surface by neglecting capillary pressure. Fetkovich et al. included gas/oil relative permeability effects on oil production for solution-gas drive through the pressure-ratio term. This assumes that the oil relative permeability is a function of pressure. It is known that gas/oil relative permeability is a function of fluid saturation, which depends on fluid/rock properties.

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