Bulletin 49 state of illinois department of registration and education selected analytical methods for well and aquifer evaluation by william c. Since the beginning of this century the shale oil production has increased from practically zero to currently supply almost half of the u. A virtually useless analysis method that is available only because it is widely known. For a buildup after a single drawdown period at rate q during t p. Well test analysis is a critical tool to understand well and reservoir performance. The loglog plots, however, then to minimize the differences in the shape of the various type curves. Petroleum engineers face the daily challenges of designing and testing wells. Type curves provide a powerful method for analyzing pressure drawdown flow and buildup tests. Everything you always wanted to know about well test analysis but.
Example well showing the positioning of three points that define the initial decline curve in a well with 19 or more months of production data. Automatic type, curve matching for well test analysis onepetro. Match model parameters to data by regression steps 24 are well understood. The additional information required derives from a variety of sources, such as. The numerical solution and resulting type curves cover the transition range between the limiting cases of negligible inertial effects and of damped oscillation that have been treated by others. For well testing it is the pressure and the production rate equiva lently, injection.
Second, production data must be graphed according to the requirements of the type curve being used for the analysis. This can be performed by making a copy of the type curve, and cha nge the date series to drawdown data. Attempting to force a match between the buildup data points and a drawdown curve would result in a type curve located too high on the set of curves and therefore in inaccurate results. Analysis with the theis method is performed by matching the theis type curve to drawdown data plotted as a function of time on double logarithmic axes. The conventional type curve analysis method was used to interpret the aforementioned interference test data. Estimate put and its derivative dpud ln t from the data 2. To be able to interpret the results of well test analysis 4. Typecurve analysis using the pressure integral method. Two examples of slug test analysis show that precise results depend on accurate measurements of water level displacement 1% of initial value. Unlike any other oil and gas surveillance activity, a pressure transient test provides information about well and reservoir performance permeabilitythickness kh and skin s, hydraulic connectivity over large volume and average reservoir pressure. Introduction the purpose of this paper is to introduce new type curves and type curve plotting functions that allow unique analysis of noisy well test data. Conventional well test analysis has been developed pri marily for constant flow.
Fundamentally, type curves are preplotted solutions to the flow equations, such as the diffusivity equation, for selected types of formations and selected initial and boundary conditions. This course consists of lecture presentations and doing exercises using pcs and a software featuring all the latest analysis techniques. The positioning of these three points represents the handfit to. Gringarten type curves 3 plot the measured pressure drop. On loglog scales, the data curve follows a unit slope straight line as described by the early time. Estimates original fluidinplace, permeability, skin, and fracture halflength.
A new set of type curves simplifies well test analysis, world oil may, 1983 95106. Yearonyear stability in remaining proveddeveloped reserves 1p is the most positive impact of applying a consistent type well approach to. To understand the fundamental principles of well testing 2. Recently developed type curves are presented, which greatly sim plify the evaluation of builduptype well test information. It is possible to add several pressure responses, and therefore to describe the well behavior after any rate change. Semilog analysis type curve analysis well test concepts and design. An example of a well test interpretation procedure horner analysis, see page.
Therefore, a unique solution is often difficult to obtain, especially when the well test is short. This paper introduces a methodology for interpreting well test data by utilizing more sensitive semilog type curves. Type curve analysis of inertial effects in the response of a. Item analysis uses statistics and expert judgment to evaluate tests based on the quality of individual items, item sets, and entire sets of items, as well as the relationship of each item to other items.
When a match is found between data and a type curve, the parameters that. Well test types draw down open the well with constant rate decreasing bottom hole pressure build up test shutin the well increasing bottom hole pressure injection fall off test different fluid type the fluid is injected increasing bottom hole pressure shutin the well decreasing the bottom hole pressure. Tabulated type curve data not a complete set, draw down data, plotted type curve and drawdown curve in microsoft office excel 2007 x plot the drawdown curve with the same size and scal e as the type curve. The common link between the two sections is the exponential decline curve. An automatic type curve matching computer program offers a means to alleviate the parameteradjustment phase of well test analysis. The type curve parameters are then derived from these coefficients. The earlytime portion is derived from transient flow equations which come from the field of well test analysis, whereas the latetime portion consists simply of the arps typecurve. Type well analysis improves decline curve estimation. Type curve interpretation of latetime pumping test data in. These methods are, the nonequilibrium type curve method, the modified nonequilibrium straight line method, the stepdrawdown analysis developed by water survey staff members, and the analysis of an. Today, commercial software can generate the type curve families on the computer screen, enabling a much more flexible and userfriendly analysis. Well test analysis for wells produced at a constant.
An excel tool for teaching theis method of estimating aquifer. Selected analytical methods for well and aquifer evaluation. Estimates original fluidinplace, permeability, and fracture halflength for vertical wells. We observe that the curve is approximately straight between 101 and 102. Yearonyear stability in remaining proveddeveloped reserves 1p is the most positive impact of applying a consistent typewell approach to. The type curve is also useful to analyze pressure buildup tests and for gas wells. A new set of type curves simplifies well test analysis. Semilog type curve for interpretation of well test data.
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. Analysis of shorttime transient test data by typecurve matching. Such a program will shorten the analysis turnaround time and improve the quality of interpretation. Given measured production rates for a well, a type curve model can be convolved. Automatic type, curve matching for well test analysis article pdf available in spe formation evaluation 33. Originally, type curve families were printed on specialized usually loglog coordinates with dimensionless parameters defining the x and y axes. It investigates the performance of items considered individually either in relation to some external criterion or in relation to the.
Geologists, drilling engineers, production engineers and reservoir engineers with 15 years experience. The dimensionless pressure derivative plot is a more powerful diagnostic tool. Kucuk 1978 developed type curves for the tran sient rate and cumulative production for constant pressure production with elliptical flow. Introductory well testing 6 contents 9 interference test type curve matching 43 9. A singlepoint test is conducted by flowing the well at a single rate until the bhfp is stabilized. An alternative to classical well testing is numerical simulation. By graphing the reciprocal rate versus time for a well producing at constant pressure, one can then use the appropriate type curve to analyze the field data. From fetkovich type curves, future performance can be forecast along with estimates of ooip ogip and ultimate recovery. Basic concepts in well testing for reservoir description. Procedure for calculating estimated ultimate recoveries of. Since pressure information can be captured without shutting the well in and without the loss of cash flow, the frequency of testing can be significantly increased and changes in operating performance identified more quickly than is practical with conventional testing. Typewell analysis improves decline curve estimation. This paper presents new type curves and type curve plotting fr. Problem definition 8 when water is withdrawn at a constant volumetric rate q from a well of negligible radius fully penetrating a uniform confined aquifer of infinite lateral extent, the vertically averaged drawdown s evolves according to the well known theis 1935 equation.
A method for quantifying well and reservoir parameters such as permeability, skin, fracture halflength, dualporosity parameters, and others, by comparing the pressure change and its derivative of the acquired data to reservoir model curve families, called type curves. This is the superposition principle van everdingen and hurst, 1949. Look for the portion of an underlying type curves matching the data best. Section through nevius test site, near lamar, cola. The pressure measurement points of well s6j3 were subject to the influence of the ambient temperature and they fluctuated or jumped to some extent. This type of test was developed to overcome the limitation of long testing times required to reach stabilization at each rate in the flowafterflow test. This type of analysis is the main engine for doing a well test analysis in pie. The new type curves require a number of these functions provide more unique type curve dimenaionleas variables, some of hich are not in matches for noisy dst% because the integral of common use. Well test style type curve analysis with integration for data smoothing. Pdf typecurve analysis using the pressure integral method. Tests were performed and analyzed in the chingshui field, taiwan see ramey and kruger, eds. Fetkovich type curve analysis was intended to be a rapid way to estimate performance when a well is producing at a constant bottom hole flowing pressure bhfp, which is the same as what people usually do in well test analysis. The diffusivity equation used to generate the well test analysis solutions is linear. Course attendees will receive a textbook on well test analysis written by dr.
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