The theory of all decline curve analysis begins with the concept of the nominal instantaneous decline rate a, which is defined as the fractional change in rate per unit time. Since the beginning of this century the shale oil production has increased from practically zero to currently supply almost half of the u. The three parameters needed for hyperbolic decline curve analysis can be determined by a new method developed for a computer spreadsheet optimizer routine. Typewell analysis improves decline curve estimation. Cutler 1924 also used the loglog paper to obtain a straight line. Procedure for calculating estimated ultimate recoveries of.
Development of universal decline curve analysis technique. Finally, the cumulative recovery should result in a reasonable recovery factor, based on volumetrics. To assess the accuracy of decline curve analysis, or any forecasting technique, it is helpful to compare a hindcast to actual production history. A decline curve analysis model based on fluid flow mechanisms. Decline curve analysis in east almabrouk fieldcase study alfitouri ibrahim jellah abstract. We also found that application of pressurecorrected rates in decline curve analysis dca may substantially improve the interpretation of data from unconventional oil wells flowing under unstable operating conditions. Case study of a lowpermeability volatile oil field using individualwell advanced decline curve analysis. Analyzing well production data using combinedtypecurve and declinecurve analysis concepts ram g. A b factor is a hyperbolic exponent used in the arps decline curve equation to model either hyperbolic or exponential production decline, depending on the reservoir and production characteristics. This paper focuses on the development of a technique for the determination of actual fracture length of a hydraulic fracture. Please direct your comments and questions to the author, dr.
Typewell analysis improves decline curve estimation oil. Another way of representing the decline rate is based on rate q and the decline exponent constant b. Model and field case studies show the benefits of this technique as a productiondeclineanalysis tool in forecasting the waterflood production decline and the ultimate oil recovery. Fetkovich hydraulically fractured well type curve analysis can be added to improve confidence in. Fetkovich recognized that decline curve analysis was only applicable during the depletion period ie. 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. For exponential decline it is a constant with time. A program takes less time comparing with hand analysis.
Forecasting product stream an oilgas property estimation goes through several development stages. Crains petrophysical handbook reserves from decline curve. The initial decline rate controls the rate at which the type curve declines is generally between 40% and 85%. Yearonyear stability in remaining proveddeveloped reserves 1p is the most positive impact of applying a consistent typewell approach to. Functions included for computing rate, cumulative production. When b 1, it is a harmonic model and when b 0, it yields an exponential decline model. Decline curve analysis in east almabrouk field case study ijstr. Working with decline curves phdwin economics and reserves. Decline is proportional to a fractional power b of the production rate 0 b decline.
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. Calculate ooip using 35% recovery factor if the reservoir has undergone tertiary recovery. Current models used to forecast production in unconventional oil and gas formations are often not producing valid results. Vol volume under the curve segment adjusted for historical production. The most popular decline curve is that which represent the decline in the oil or gas. Initial monthly production rates compared to hyperbolic b factor for wells with more than. Before the availability of computers, decline curve analysis was performed by hand on semilog. The difference from one well to another indicates, that the wells are far from the injector wells. The effective decline factor d is a stepwise function that is in better agreement with data recording practices. The cumulative oil production after the production decline upon decline time t can also be evaluated based on the total reservoir compressibility. Depletion has a fundamental role in the extraction of finite resources and is one of the driving mechanisms for oil flows within a reservoir.
But this is where decline curve analysis algorithms are these daysat a fork in the road, and the one you. The use of type curves for decline curve analysis is demonstrated with examples. With inputs for multiple scenarios, running sensitivities on the dca inputs is fast and easy. Actual hydraulic fracture length determination using a new technique for shale fracturing data analysis in real time.
Life cycle reserves appraisal using an integrated workflow process for tight gas sands. Traditionally, decline curve analysis dca is commonly used to predict gas production and its decline trend to determine the estimated ultimate recovery eur, but its analysis cannot be used to analyze what factors influence the production decline. Decline curve analysis is the most currently method used available and sufficient 1. Depletion rate also can be connected to decline curves. Production decline analysis is a traditional means of identifying well production problems and predicting well performance and life based on real production data. Based on the behavior of hydrocarbon system, b value is ranged from 0 to 1 for every. Decline curve analysis has been called the most commonly used and misused technique for forecasting future production and remaining reserves. Production decline curves can be classified as follows.
Gas reservoir declinecurve analysis using type curves with. Decline analysis curve an overview sciencedirect topics. Decline curve analysis has been used to provide a bestfit equation for series of data point by. Pdf modern decline curve analysis for oil fields fady henein. The three parameters needed for hyperbolicdeclinecurve analysis can be determined by a new method developed for a computer spreadsheet optimizer routine. Analyzing well production data using combinedtype curve and decline curve analysis concepts ram g. Analyzing well production data using combinedtypecurve and.
Dm minimum decline rate decline rate at which hyperbolic projection becomes exponential segment null projection pressing this button causes a 0 or null projection to be input for the 1st decline segment. Pdf analysis of production decline in waterflood reservoirs. The trouble in applying decline curve techniques for shale oil wells is the lack of production history. 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. Procedure for calculating estimated ultimate recoveries of bakken and three forks formations horizontal wells. 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. A curve fit of past production performance is done using certain standard curves. Decline curve analysis is a long established tool for developing future outlooks for oil production from an individual well or an entire oilfield.
Gas reservoir declinecurve analysis using type curves. Empirical decline curve analysis of oil production data gives reasonable answer in hyperbolic type curves situations. This allows type curve matching of the exponential decline curve for a reservoir with any shape. Abstract advanced decline curve analysis course this oneday course will show how loglog type curve analysis can be performed on declining production rate data completely analogous to the loglog type curve matching procedure presently being employed with. Procedure for calculating estimated ultimate recoveries. A depleted natural gas reservoir was evaluated for its potential to become an underground baseload storage. Decline curve analysis for estimating eurs and ooips. Dt in the equations b and d are empirical constants that are determined based on historical production data. Determine the amount of prior production and add that to the partial eur for the actual estimated ultimate recovery. A normalized time has been developed that linearizes the rate decline vs. Decline curve analysis three basic decline curve equations all of the equations give you the ability to predict cumulative production or production rate at some point in time. Arps decline curve analysis in r functions for arps declinecurve analysis on oil and gas data. Decline curve analysis is a means of predicting future oil well or gas well production based on past production history. Apr 16, 2015 this feature is not available right now.
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. Production decline analysis is the analysis of the past trends of declining production performance, that. Calculate ooip using 35% recovery factor if the reservoir has undergone tertiary recovery then also determine the tertiary eur. Production decline curve analysis the road not taken. Approaches of decline curve analysis used for naturallyfractured reservoirs developed by water flooding have been few. This program is provided by gotech as is and gotech does not fully support this program.
A new theory for interpreting rate decline trends in. Decline curve analysis models are frequently used but still have many limitations. Dca parameters are easily input to fit your data and forecast production on the fly. Analysis using the li horne model for production data from spraberry oil field. Analysis methods traditional background for traditional analysis decline curve analysis is a graphical procedure used for analyzing declining production rates and forecasting future performance of oil and gas wells. Decline curve analysis is a reservoir engineering empirical technique that extrapolates the trends in the production data from oil and gas wells. The hyperbolic curve requires estimation of both di and the exponent b. Jul 05, 2016 production decline curve analysis the road not taken.
Basic concepts in decline curve analysis by mike fetkovich table of contents tape 1 click here to watch the entire fetkovich course from beginning to end of tape 1. Decline curve analysis oil reserves petroleum reservoir. Production decline curve an overview sciencedirect topics. Prediction of reservoir performance applying decline curve. The harmonic decline is the special case of equation 1 when the b exponent equals one.
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. Decline curve analysis relates past performance of oil and gas wells to future performance. What factors control shale gas production and production. Conventional decline curve analysis should be used only when mechanical conditions and reservoir drainage remain constant and the well is producing at capacity 197. Definition of decline curve parameters society of petroleum. The driving factor for this was the decline of natural gas prices concurrent with a rise in oil prices. The decline curve equations assume that production decline is proportional to reservoir pressure decline. Development of universal decline curve analysis technique for. Pdf on mar 1, 2005, kewen li and others published verification of decline curve analysis. We investigate the applicability of a densitybased approach for decline curve analysis for production at constant bottomhole pressure in dualporosity gas systems. Decline curve analysis in unconventional resource plays. Application of extended exponential decline curve analysis to the.
This allows typecurve matching of the exponential decline curve for a reservoir with any shape. Unconventional datadriven methodologies forecast performance. Includes exponential, hyperbolic, harmonic, and hyperbolictoexponential models as well as the preceding with initial curtailment or a period of linear rate buildup. Production decline curve analysis is a traditional means of identifying well production problems and predicting well performance and life based on measured oil well production. Prediction of reservoir performance applying decline curve analysis. Depletion and decline curve analysis in crude oil production. Another factor which must be recognized is that the production rate referred to in. While my work does not account for the complex differences among various shale oil plays due to. Pdf verification of decline curve analysis models for production. Case study of a lowpermeability volatile oil field using. In advanced production decline analysis and application, 2015.
Holdaway, louis fabbi, and dan lozie, sas institute inc. Summary this paper presents new production decline curves for analyzing. The case of eagle ford linnea lund production of oil and gas from shale is often described as a revolution to energy production in north america. Production data analysis of naturally fractured reservoir. Unconventional datadriven methodologies forecast performance in unconventional oil and gas reservoirs keith r. A decline curve analysis model based on fluid flow. Decline curve analysis using arps empirical algorithms. Abstract linear and nonlinear regression analysis were carried out on arps decline curve by using analytical natural. Arnold and anderson 1908 presented the first mathematical model of dca. Drillnomics takes a visually fit curve and calculates the production from that curve. Production forecasting decline curve analysis petrowiki.
Drillnomics uses proprietary calculations that closely relate to the b factor, initial decline rate, and initial rate used in the arps decline curve equation. Hyperbolic decline curves have been used in many cases, particularly in the late history of pressure supported production. Decline curve analysis dca is used to predict the future production of oil and gas, and it has been widely used since 1945. Analyzing well production data using combinedtypecurve. When traditional decline curve analysis models are used in shale formations, arps b values greater than 1 are commonly obtained, and these values yield infinite cumulative production, which is nonphysical. He only indicated that exponential decline b0 is most common and that the coefficient b generally ranges from 0 to 0. Spreadsheet determines hyperbolicdecline parameters oil.
Model and field case studies show the benefits of this technique as a production decline analysis tool in forecasting the waterflood production decline and the ultimate oil recovery. Methods of decline curve analysis for shale gas reservoirs mdpi. It uses empirical decline models that have little fundamental justifications. An advanced approach for decline curve analysis, which is applicable for changes in pressure or drainage, has been presented by fetkovich 267, 268. Conversely, predictions from the decline history assumes that no significant changes in these factors will take place.