The nominal or instantaneous decline rate, r, of the skin factor, s. Analysis of production decline curves digital edition. Calculate ooip using 35% recovery factor if the reservoir has undergone tertiary recovery then also determine the tertiary eur. Fetkovich used the curves with values of b between 0 and 1 hyperbolic and harmonic decline for matching solutiongasdrive depletion and gas reservoir depletion. Nodal analysis procedures not covered explicitly in this book tend to rely heavily on ipr techniques andor decline curve analysis and have been of limited value in unconventional fields. If you have a fairly fast connection, you may wish to download the entire package. Decline analysis curve an overview sciencedirect topics. Prediction of reservoir performance applying decline curve. Workflow for applying simple decline models to forecast. That will be is the end of oilfield production life, conditioned by present technology, production cost, contracts and state regulations.
The conventional analysis of production decline curves for oil or gas. Black box algorithm from a third party calculates the eur for this well at nearly 1,200,000 bo1,770,000 depending on method, which is nearly 2x3x the p90 from. A decline curve analysis model based on fluid flow. The production decline curves have two main functions, including a to determine the reservoir permeability parameter by matching the production decline curve with it, which belongs to quantitative analysis, and b to diagnose the production performance characteristics, that is, to qualitatively judge the.
Advanced production decline analysis and application. Decline curve analysis is not a curvefitting exercise, and it should not be limited to a single ratetime graph of each well in isolation, much less just any ratetime graph created by the sloppy defaults of most graphing programs. However, most curve analysis is done by computer today, promoting a blackbox approach to engineering and leaving engineers with little background in the fundamentals of decline analysis. Pdf verification of decline curve analysis models for.
Exponential decline using the b factor value of zero is exhibited by a straight line on a semilog graph, whereas hyperbolic decline with b values ranging from 0. Spe 167253 decline curve analysis for unconventional pdf author. The decline type of well 1 is exponential, and the remaining reserve calculated. Includes exponential, hyperbolic, harmonic, and hyperbolictoexponential models as well as the preceding with initial curtailment or a period of linear rate buildup. For exponential decline it is a constant with time. The hyperbolic curve requires estimation of both di and the exponent b. Title arps decline curve analysis in r description functions for arps declinecurve analysis on oil and gas data. Spe 167253 decline curve analysis for unconventional pdf keywords. Oil depletion is the decline in oil production of a well, oil field, or geographic area. Crains petrophysical handbook reserves from decline curve.
Abstract linear and nonlinear regression analysis were carried out on arps decline curve by using analytical natural. If your connection is slower, you will want to download the files separately. In recent years, production decline curve analysis has become the most widely used tool in the industry for oil and gas reservoir production analysis. Dca parameters are easily input to fit your data and forecast production on the fly. Pdf hyperbolic decline parameter identification using. Pro duction prediction based on reservoir simulator 0. However a great number of studies on production decline analysis are still based on this empirical method. Cutler 1924 also used the loglog paper to obtain a straight line for hyperbolic decline, so the curve shifted horizontally. Arps exponential decline marked in red results in an excellent fit even at an early production time of 3 days. The normalized probability density function for uniform distribution is given by.
The hubbert peak theory makes predictions of production rates based on prior discovery rates and anticipated production rates. In advanced production decline analysis and application, 2015. A new empirical model has been developed and used as an alternative to traditional decline curve analysis with the arps equation. The decline curve analysis template for tibco spotfire allows you to quickly plot oil forecast curves on top of your actual production, using the arps hyperbolic equation.
Many published papers have tried to interpret the arps 4 decline equation theoretically. The arps decline curve analysis approach4 was proposed nearly sixty years ago. Decline curve analysis is the most currently method used available and sufficient 1. Mead9 noted in his discussion of b factor decline curve exponent that. Advanced production decline analysis and application 1st. Gas reservoir declinecurve analysis using type curves with. Larkey 1925 proposed the leastsquares method to extrapolate the. The hyperbolic decline curve has a good fit to production data and in many cases the curve is close to harmonic. To estimate ooip we need to know the estimated ultimate recovery eur and the recovery factor we can get eurdirectly from a graph we use a standardized average recovery factorof 35% for all reservoirs undergoing. Advanced production decline analysis and application starts from the basic concept of advanced production decline analysis, and thoroughly discusses several decline methods, such as arps, fetkovich, blasingame, agarwalgardner, npi, transient, long linear flow, and fmb. Decline curve analysis is an exercise in seeing, understanding and predicting the reservoir and operational dynamics. Production data analysis of naturally fractured reservoir. The most popular decline curve is that which represent the decline in the oil or gas.
With inputs for multiple scenarios, running sensitivities on the dca inputs is fast and easy. We found in the pod and operating the pod wells simpson 1 that any analysis that treats an unconventional reservoir as darcy flow through a porous. Thus, a major advantage of this decline trend analysis is inclusion of all production and operating conditions that would influence the performance of the well. Decline curve analysis is a long established tool for developing future outlooks for oil production from an. Depletion and decline curve analysis in crude oil production. Development of universal decline curve analysis technique. Oil, gas and water saturation levels are important factors and refer to the. Nominal decline is a continuous function and it is the decline factor that is used in the various mathematical equations relating to decline curve analysis. Production declinecurve analyses are the most widely used tool in the industry for oil and gas reservoir production analyses. Case study of a lowpermeability volatile oil field using. An ideal decline curve for shale wells would be able to forecast linear flow followed by boundarydominated flow.
Analysis of production decline curves poston, steven w. In this study decline analysis was applied for wells, and whole field. Decline curve analysis in unconventional resource plays using. Decline curve analysis is on of the oldest and one of the most. The decline curve will find the economic limit line at some time. In recent years, production declinecurve analysis has become the most widely used tool in the industry for oil and gas reservoir production analysis.
A value of b 0 corresponds to exponential decline, values of b 0 and b 1 corresponds to harmonic decline. A new theory for interpreting rate decline trends in. Original oil in place values calculated from ratetime analysis for individual wells are used with recoverable reserve projections from the decline analysis to obtain fractional recoveries for each well. The remaining reserve calculation becomes more reliable whenever data points are well screening.
Production forecasting decline curve analysis petrowiki. The new model is based on the concept of logistic growth models. B oi formation volume factor for oil at initial conditions reservoir bbl barrels stb stock tank barrels from lab data. Production decline curve an overview sciencedirect topics.
The empirical arps decline equation represents the relationship between. Arps method marked in red can only fit bdf decline which does not. A value of b 0 corresponds to exponential decline, values of b 0 and decline, and a value of b 1 corresponds to harmonic decline. Recent efforts in the area of decline curve analysis have been directed toward a purely computerieed statistical approach, its basic objective being to arrive at a unique unbiased interpretation. Decline curve analysis free download as powerpoint presentation. Oil well ratetime analysis continued oil well with n1 b. Arnold and anderson 1908 presented the first mathematical model of dca. The effective decline factor d is a stepwise function that is in better agreement with data recording practices. The report also investigates how the density of the petroleum affects the decline curve. The exponential decline rate used is arbitrary, and the value picked greatly effects the results of the forecast. Prediction of reservoir performance applying decline curve analysis. However, the application of pdca in shale gas reservoirs is relatively new. Decline curve analysis has been called the most commonly used and misused technique for forecasting future production and remaining reserves.
The decline curve shows how oil and gas production rates decrease over time. Decline curve analysis three basic decline curve equations. Functions included for computing rate, cumulative produc. Values of b 1 are not consistent with decline curve theory, but they are sometimes encountered, and their meaning is explained below. This book will serve as an authoritative reference on modern production declinecurve analyses, including details of some recent advances in the technology. Pdf reserve estimation using decline curve analysis for. Factor analysis and item analysis applying statistics in. Decline curve analysis oil reserves petroleum reservoir. Hyperbolic decline curves have been used in many cases, particularly in the late history of pressure supported production. Williams for your safety and comfort, read carefully ebooks spe 167253 decline curve analysis for unconventional pdf this our library download file free pdf ebook. Probabilistic decline curve analysis pdca methods have been developed to quantify uncertainty in production forecasts and reserves estimates.
For boundarydominated flow, fetkovich showed the arps family of curves with b as a parameter. It is too early to determine whether the alternative decline curve that is tested, the scaling decline curve, has a better fit in the long term. Decline curve analysis dca is used to predict the future production of oil and gas, and it has been widely used since 1945. The fullsize fetkovich typecurves can be ordered from the book order. He only indicated that exponential decline b0 is most common and that the coefficient b generally ranges from 0 to 0. Decline curve analysis in east almabrouk field case. The cumulative oil production after the production decline upon decline time t can also be evaluated based on the total reservoir compressibility. Production decline curve analysis the road not taken. Decline curve analysis models are frequently used but still have many limitations.
A practical systematic introduction to each method helps the reservoir. Depletion has a fundamental role in the extraction of finite resources and is one of the driving mechanisms for oil flows within a reservoir. This course will give the learner a better understanding of how fundamental reservoir properties and drive mechanisms affect the shape of the production decline curve and how to avoid many of the mistakes commonly found in decline curve forecasts. The b 0 case is for exponential decline of a liquid reservoir. A conceptual horizontal shalewell with multiple traverse hydraulic fractures was simulated and production is shown by the green curve. Finally, the cumulative recovery should result in a reasonable recovery factor, based on volumetrics. The harmonic decline is the special case of equation 1 when the b exponent equals one. This method has been proved useful for decline curve analysis in order to estimate the initial decline rate d, initial rate qi and the hyperbolic exponent b, which can be used to plot the. Depletion rate also can be connected to decline curves. Hubbert curves predict that the production curves of nonrenewing resources approximate a bell curve. Decline curve analysis is a means of predicting future oil well or gas well production based on past production history. Petroleum related trade journals and statistical yearbooks from various oil com. A method for estimating reserves and predicting production in oil reservoirs and oil fields. Determine the amount of prior production and add that to the partial eur for the actual estimated ultimate recovery.
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