Pressure Transient Analysis (PTA) deals with the processing and analysis of small or large volume of raw pressure and rate (and/or cumulative volume) data collected during the controlled testing of oil and gas production wells or water and gas injection wells under flowing, injection or shut-in conditions. Results of the analysis can provide important qualitative and quantitative information about reservoir description, well performance, reserves and/or contacted volume.
Special tests may include multi-rate tests for the estimation of gas well deliverability and interference/pulse tests for determining inter-well communication. Information obtained from well tests is essential and helpful for the effective management of oil and gas reservoirs. PTA methodology has been mainly based upon analytical solutions but is also utilizing numerical simulators for complex reservoir geometries.
The latest addition to PTA has been the use of deconvolution which combines multiple rate flow and shut-in periods into an equivalent single rate response. This has a potential of investigating deeper into the reservoir.
Transients+ is a pressure transient analysis (PTA) software package. It is a comprehensive, state-of-the-art, easy to use well test design and analysis tool. Transients+ allows handling of huge volume of raw pressure, rate and cumulative volume data. Its GUI-based data editor facilitates quick and easy editing of these and other data in desired units.
It also allows plotting of test data on Cartesian, Semi-log and Log-log (Diagnostic) graphs using appropriate pressure and derivative functions for model recognition as well as analysis. Transients+ has a full suite of reservoir and well completion models along with numerical modeling capability which allows it to handle PTA of both simple and complex reservoir systems. The software is intuitive, interactive, and user friendly, while allowing for advanced analysis.
Data Import & Processing
Transients+ offers convenient pressure and rate data import for any no. of gauges.
Data can be conveniently copy-pasted into the input field or can be read directly from the Text or Excel file with Import Assistant.
Data can also be easily corrected for the time and pressure shifts.
All the DD & BU periods are automatically recognized and divided upon.
Isolated inconsistent pressure and rate data points can be conveniently edited for through the visual editor.
This is a very powerful tool offering distinctive features including:
Edit/Delete individual or group of data points
Data Interpolation & Averaging
Consistency between rate and cumulative volume data are ensured
Data curve shifting with area under the curve preserved
Data curve fitting
The edited data can be directly loaded into main interface for further analysis
Transients+ contains multitude of standardized plots:
Wellbore Storage Analysis
Straight Line Analysis
Infinite Acting Radial Flow (IARF)
Pressure drop and the log derivative (Bourdet derivative) are displayed in this plot together.
Transients+ conveniently displays the typical flow-regimes associated with the selected reservoir type.
The analysis results are also displayed in the floating results window.
In addition, the results can automatically be exported to the regression analysis as an initial guess.
Transients+ has built-in Type-curves for multiple reservoir types:
Double Porosity (PSS)
Double Porosity (Transient)
Finite Conductivity wellbore fracture
Infinite Conductivity wellbore fracture
The observed data curves can be dragged along to get the best fit and the resultant parameters are displayed in the results window.
Regression Analysis, also called as Automatic Type Curve Matching in Transients+, involves regression to arrive at an optimized set of parameter values. A sample set of panels is shown on the right and is used during the regression process.
Regression has flexibility of selecting particular range of data for a chosen flow period with selective time interval-based weighting.
In addition, the results can automatically be exported to the simulation analysis.
Transients+ has Simulation Analysis option available to simulate the pressure data and to compare with the entire pressure history based on the estimated set of model parameters.
This analysis also allows to perform sensitivity study for a given set of parameter(s) to gauge the impact on the overall pressure match.
Note: In the above plot, the last BU period is tuned for. Hence the match is excellent for this period while, for rest of the data, the match is relatively poor
Rock & Fluid Properties
Industry-standard fluid property correlations are built-in.
Following correlations are available:
Formation Volume Factor (FVF):
Alternatively, user can also provide the property values manually.
Reservoir Type Models
Transients+ includes a comprehensive list of built-in reservoir models which allows analyzing commonly encountered reservoir types:
Finite/Infinite Conductivity Fracture
Two Layer Models
Boundary Models include-
Infinite, No-flow, and Constant Pressure Boundary
Well Geometry Models
Transients+ provides various well completion modeling options which involves:
Vertical, Horizontal, Segmented Horizontal, Slanted, and Partial Penetration
The Deliverability Analysis allows user to compute the AOF and the Empirical (n/c) or Theoretical (a/b) model parameters.
Widely used test types are built-in:
Isochronal Test, and
Modified Isochronal Test
Deliverability Analysis: Results Window
This mode allows user to analyze the interference, or pulse test data by constructing the field geometry and importing the multi-well production history.
Multi-parameter regression analysis can be used to tune-in the model parameters.
In addition, sensitivity analysis can also be performed.
Pressure Contour Map
Transients+ has the Deconvolution module which enables combining several flow/shut-in periods into a single draw-down flow period pressure response. If analyzed carefully, this technique enables us to increase the radius of investigation for the given data set.
Transients+ offers unique perspective of the deconvolution process by offering a series of Performance Plots, tracking the convergence performance.
This in turn allows user making a decision whether the deconvolution exercise has resulted in any meaningful, additional information.
Deconvolved data can be automatically sent for further PTA analysis.
Transients+ has been incorporated with Numerical Simulation Analysis option, which helps to solve complex PTA problems difficult to analyze with conventional analytical techniques.
A full-fledged 3D finite difference simulator has been integrated into the Transients+. A simple GUI has been developed for easy input and convenient output display with the help of 3D visualization as well as 2D plots.
Currently more features are being added to this module.
Reporting & Help Menu
Transients+ reporting option allows “drag and drop” of individual analyses into the report viewer.
The resulting report can easily be saved, printed, and edited upon per user requirement.
Transients+ has very useful feature called Composite Plot and it allows user to:
Compare results for any no. of flow periods on a single plot e.g. log derivative curves can be compared for multiple flow periods.
In addition, user can also generate a composite plot of multiple analyzes which can be extremely handy for presentation purposes
Transients+ has detailed On-Line Help Menu covering:
Basic analysis procedures
Extensive technical literatures
In addition, there are multitude of sample cases covering simple as well as advanced scenarios.
FOR GENERAL QUESTIONS
Fax: +1 972-473-2667
FOR WRITTEN INQUIRIES
Plano Research Corporation
5240 Tennyson Parkway, Suite 201
Plano, TX 75024, USA