Comparison of empirical decline curve analysis for shale wells a thesis. The effective decline factor d is a stepwise function that is in better agreement with data recording practices. Decline curve analysis is a long established tool for developing future outlooks for oil production from an individual well or an entire oilfield. Production forecasting decline curve analysis petrowiki. Jul 05, 2016 production decline curve analysis the road not taken. The nominal decline factor d is defined as the negative slope of the curve. Data points lying outside the type curve represent transient flow.
A new direction for decline curve analysis was given by slider 2 with his development of an overlay method to analyze ratetime data. We have calculated underlying decline rates based on our analysis of. A decline curve analysis model based on fluid flow mechanisms. Initial flowrate in the context of the exponential decline curve analysis, this is the flowrate essentially on the first day of production, although the average flowrate for the first full month could also be used.
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. Because his method was rapid and easily applied, it was used extensively by ramsay in his evaluation of some 200 wells to determine the distribution of the decline curve exponent b. 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. This analysis uses three methods for predicting the deline of a reservoir, exponential, harmonic and hyperbolic. Fetkovich recognized that decline curve analysis was only applicable during the depletion period ie. In recent years, production declinecurve analysis has become the most widely used tool in the industry for oil and gas reservoir production analysis. The exponential decline equation can be derived from equation 1 with a bexponent of zero. Decline curve analysis in unconventional resource plays. It uses empirical decline models that have little fundamental justifications. Raghavan and ohaeri 19, and sageev zo also examined the rate dedine behavior of naturally fractured reservoirs. Production decline curve an overview sciencedirect topics. L337tech llc also offers paid training for quickdecline.
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. Factors that affect sandface flowing pressure are rate controlled wells, changing. Functions for arps declinecurve analysis on oil and gas data. In a context of energy resources demand and oil prices volatility, decline curve approaches are said to be a simple and efficient tool to identify reservoirs potential as well as to assess the economical viability of a development plan. The new model is based on the concept of logistic growth models. The decline curve will find the economic limit line at some time. For exponential decline it is a constant with time. The exponential decline rate used is arbitrary, and the value picked greatly effects the results of the forecast. Shelf facies consists of a complex of oolitic, pelletoidal, bioclastic and pisolitic grainstones.
Equation 1615 suggests a plot of q t versus g pt on a semilog scale and will yield a straight line with a negative slope of d i q i and. Decline curve analysis merupakan cara paling simple dalam menentukan estimasi perolehan maksimum oil dan forecast sumuran maupun lapangan. The hyperbolic curve requires estimation of both di and the exponent b. The graph of production rate versus time was plotted on the semilog graph see fig. The theory of all decline curve analysis begins with the concept of the nominal. The basic two plots for harmonic decline curve analysis are based on these two relationships.
Unconventional resources chapter kappa engineering. Decline curve analysis petroleum engineering practise. We investigate the applicability of a densitybased approach for decline curve analysis for production at constant bottomhole pressure in dualporosity gas systems. Calculate ooip using 35% recovery factor if the reservoir has undergone tertiary recovery then also determine the tertiary eur. Decline curve analysis is the most currently method used available and sufficient 1. Another way of representing the decline rate is based on rate q and the decline exponent constant b. Analysis of production decline curves poston, steven w. 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. Abstract linear and nonlinear regression analysis were carried out on arps decline curve by using analytical natural.
Phdwin offers evaluators a tool that combines an intuitive interface with sophisticated functionality. The hyperbolic decline curve has a good fit to production data and in many cases the curve is close to harmonic. The report also investigates how the density of the petroleum affects the decline curve. These work indicate that the double porosity model predicts an initial high flowrate followed by p sudden rate decline and a period of constant 1.
Development of universal decline curve analysis technique for. Decline curve analysis help exponential decline curve analysis new features display on chart allows the user to display the decline line on the chart itself decline curve start date when you want the decline curve to be displayed on the chart initial flowrate in the context of the exponential decline curve analysis, this is the flowrate essentially on the first day of production. Decline exponential decline rate calculation this routine presumes that recoverable reserves are known from some other source, such as volumetric analysis from log data, decline curve analysis, or material balance calculations. 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. Crains petrophysical handbook decline rate and economic life.
Production declinecurve analyses are the most widely used tool in the industry for oil and gas reservoir production analyses. Prediction of reservoir performance applying decline curve analysis. Includes exponential, hyperbolic, harmonic, and hyperbolictoexponential models as well as the preceding with initial curtailment or a period of linear rate buildup. If you have a fairly fast connection, you may wish to download the entire package.
Decline curve analysis free decline curve analysis. Quick decline allows for easy production and well data imports for most of todays modern tools. The plots can also help you choose which b factor is most appropriate for your well. Set r in the equations below to equal roil or rgas. Production decline curve analysis the road not taken. Phdwin is a fullfeatured economic and decline curve analysis program. Depletion has a fundamental role in the extraction of finite resources and is one of the driving mechanisms for oil flows within a reservoir. Finally, the cumulative recovery should result in a reasonable recovery factor, based on volumetrics. Nonaffine structure, systematic risk sources, and generalized duration, in l. Prediction of reservoir performance applying decline curve.
Quickdecline was written by petroleum engineers as a tool to make quick and easy decisions. 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. But this is where decline curve analysis algorithms are these daysat a fork in the road, and the one you. Above, the phalf is the pressure for which the coverage factor is. Petrovrs decline analysis module provides users with secure access to type curves, well profiles and production forecasts with a full history of any changes made. The most popular decline curve is that which represent the decline in the oil or gas. There are two types of decline factors often called the decline rate. Excludes ngls and unconventional shale production in the us and canada. The drillnomics di factor is a similar representation of the initial decline rate in arps and in conjunction with the b factor will enable the user to easily model the hyperbolic section of a decline curve when fitting visually to well production data. Decline curve analysis free decline curve analysis software.
Production decline analysis is a traditional means of identifying well production problems and predicting well performance and life based on real production data. A model is said to fit fairly well when the regression coefficient. In advanced production decline analysis and application, 2015. Since the beginning of this century the shale oil production has increased from practically zero to currently supply almost half of the u. Pdf verification of decline curve analysis models for. Document information click to expand document information. Decline curves are one of the most extensively used forms of data analysis employed in the evaluation of oil properties. If your connection is slower, you will want to download the files separately. Before the availability of computers, decline curve analysis was performed by hand on semilog.
These curves have been developed by combining decline curve and type curve analysis concepts to result in a practical tool which we feel can more easily estimate the gas or oil in place as well. We would like to clarify that our study and the discussions in this article are limited to twophase fluid flow. Stylised oil field production curve, describing the various stages of maturity. 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. Functions included for computing rate, cumulative production, instantaneous decline, eur, time to economic limit, and performing leastsquares best fits. Depletion rate also can be connected to decline curves. D instantaneous decline rate at time t di initial decline rate q instantaneous flow rate qi initial flow rate at start of decline n 0 for exponential decline 1 for harmonic decline 2 for hyperbolic decline. Determine the amount of prior production and add that to the partial eur for the actual estimated ultimate recovery. Decline curve analysis is an exercise in seeing, understanding and predicting the reservoir and operational dynamics. Development of universal decline curve analysis technique. Black dots represent the outliers, whereas red dots are the oil rates included in the analysis. 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. Equation 1614 indicates that a plot of 1q t versus t on a cartesian scale will yield a straight line with a slope of d i q i and an intercept of 1q i.
Decline rate and economic life crains petrophysical. Advanced production decline analysis and application. It provides users with a powerful multisegment decline curve analysis engine capable of a full range of pure and modified decline forecasts. Oil, gas and water saturation levels are important factors and refer to the. 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.
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. Material balance and decline curve analysis used as. 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. Postons industry experience includes more than 14 years in a variety of subsurface engineering, geological, and managerial roles for gulf oil. Decline analysis of oil well stimulation rule using matlab. Advanced production decline analysis and application starts from the basic concept of advanced production decline analysis, and thoroughly discusses several. Often future production is extrapolated as a straight line on semilog paper exponential or constantpercentage decline because this type of decline is the easiest to handle mathematically and graphical. Decline curve analysis is a means of predicting future oil well or gas well production based on past production history. Gas hydrate occurs mostly in marine sediments of the continental shelf. Pdf evaluation of natural gas production optimization in. 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.
This book will serve as an authoritative reference on modern production declinecurve analyses, including details of some recent advances in the technology. This book will serve as an authoritative reference on modern production decline curve analyses, including details of some recent advances in the technology. Decline curve analysis relates past performance of gas and oil wells to. A saddle has been interpreted at about 4 km in nne direction from the crest. Pdf decline curve analysis of well no ktl04 from the kailashtila gas field in northeastern. Mathematics the arps decline curve analysis approach4 was proposed nearly sixty years ago. With inputs for multiple scenarios, running sensitivities on the dca inputs is fast and easy. That will be is the end of oilfield production life, conditioned by present technology, production cost, contracts and state regulations. 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. This web application will take advantage of over 11 years of java development experience.
It is often used to estimate the recovery factor by comparing ultimate recovery with original oil in place or gas in place calculations. Reserves from decline curve analysis crains petrophysical. Decline curve analysis three basic decline curve equations. Decline curve analysis for estimating eurs and ooips.
The product will save significant man hours over traditional decline curve analysis software. Decline curves are generally easy to use, but type curves usually. Thereafter, production will decline at the exponential rate. May 02, 2019 functions for arps decline curve analysis on oil and gas data.
Dca parameters are easily input to fit your data and forecast production on the fly. Analysis of production decline curves digital edition. Hyperbolic decline curves have been used in many cases, particularly in the late history of pressure supported production. Decline curve analysisforecast forecast solution gas dengan memplot cumulative solution gas vs cumulative oil kita dapat memforecast produksi solution gas. A decline curve analysis dialog was included to allow the user to predict the economic limit for a specific lease, field, operator and county. Production data analysis of naturally fractured reservoir. The relationship between the dimensionless decline cumulative production and dimensionless decline time is shown in figure 3.
Decline curve analysis is a long established tool for developing future outlooks for oil. Decline curve analysis consists of a technique widely employed to evaluate the amount of recoverable hydrocarbons in reservoirs. Pro duction prediction based on reservoir simulator. Decline curve analysis methodology for the two fields, d4 and w1, the same approach was used in calculating the decline curve. Conversely, predictions from the decline history assumes that no significant changes in these factors will take place. A straight line relationship on the semilog graph shows that the data undergoes the empirical model of arps, j. These work indicate that the double porosity model predicts an initial high flowrate followed by. The application of decline curve analysis dca in unconventional plays could be. Limitations of decline curve analysis of naturally fractured reservoirs it is often impossible. Decline curve start date when you want the decline curve to be displayed on the chart. 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. These models include exponential decline constant fractional decline harmonic decline, and. We think several factors point to risks of accelerating declines in the. A new empirical model has been developed and used as an alternative to traditional decline curve analysis with the arps equation.
Crains petrophysical handbook reserves from decline curve. Production decline data from different types of waterdrive reservoirs were analyzed as examples of using the new decline analysis model. Depletion and decline curve analysis in crude oil production. A decline curve analysis model based on fluid flow. Advanced production decline analysis and application 1st.