UniTest® PLT groups some specific functions for comprehensively working in the interpretation of well production logs. These functions are sufficient to avoid having to depend on other particular software applications.
Once loaded well data, with UniTest ® PLT functions the user can edit and graph all characteristic well curves, as well as generate production log ready to be printed, and on the other hand, make interpretations based on model parameters, calculated fluid velocities and average log curves, indicating the estimated production of each layer in terms of oil, gas and/or water.
- Comparison of PLT logs of the same well done in different times
- Fluid velocity calculation
1. Production Logs
UniTest® PLT enable to import data from well production logs, making different channels for each registered magnitude. Such channels are gamma ray, CCL, pressure, temperature, density, capacitance, spinner and cable velocity.
The software has a function that, using loaded data, graph each curve of well log as a function of depth.
Different panels can be created including quick and easy different curves that want to be exposed. Each panel can be independently edited adding titles, names of each curve, scales, etc.
In order to facilitate graphics creation there are some buttons that automatically perform this task, gathering different curves in presets configurations.
The possibility of making zoom in specific areas it's a great help at the time of detailed analysis, as well as it's the option to shift depth of curves in order to correlate them.
Additionally, each graphic can be copied in the clipboard and be available to be pasted in other applications, in reports for example.
3. Fluid velocity calculation
Considering a linear turbine response, the information of the propeller revolutions vs. cable speeds it's combined for each direction of rotation. Using linear regression techniques, information is filtered and, for each considered depth, interpolated cable speed where spinner is zero it's obtained. In this way, curve of fluid velocity as function of depth it's obtained.
Using input data of different pipe parameters, PVT, logging tool mechanical information and different multiphase flow correlations, empirical and mechanistic, the software can model well production indicating contributions of each layer in terms of oil, gas and/or water flow.
To adjust results to real data, model curves are overlapped and compared graphically with average curves obtained from well production logging.
5. File Edition
The software has the ability to import and edit log files provided by PLT tools applications.
Technical References of UniTest® PLT
UniTest® software has several empirical and mechanistic multiphase flow models used to make interpretations.
Ansari SPE 20630
"A Comprehensive Mechanistic Model for Upward Two-Fhase Flow in Wellbores"
Ansari, A.M., Sylvester, N.D., Sarica, C., Shoham, O. and Brill, J.P., SPE 20630 presented at the SPE 65th Annual Meeting, New Orleans, September 23-26, (1990), SPE Production Engineering, pp. 143-152 (May 1994).
Baxendell & Thomas SPE 2-PA
"The Calculation of Pressure Gradients in High Rate Flowing Wells"
Baxendell, P. B., CIA. SHELL de Venezuela, Thomas, R., CIA. SHELL de Venezuela, JPT (Oct. 1961), 1023.
Beggs & Brill SPE 4007
"A Study of Two Phase Flow in Inclined Pipes"
H. Dale Beggs, SPE-AIME, U. of Tulsa, James P. Brill, SPE-AIME, U. of Tulsa. 1973.
Fancher & Brown SPE 440
"Prediction of Pressure Gradients for Multiphase Flow in Tubing"
Fancher, G. H., and Brown, K. E., Trans. AIME (1963), 228, 59-69.
Gomez SPE 56520
"A Unified Mechanistic Model for Steady-State Two-Phase Flow in Wellbores and Pipelines"
L. E. Gomez, SPE, O. Shoham, SPE, and Z. Schmidt, SPE, The University of Tulsa, R. N. Chokshi, SPE, Zenith ETX Co., A. Brown, BP Exploration and T. Notrhug, StatOil.
Hagedorn Brown SPE 940
"Experimental Study of Pressure Gradient Occurring During Continuous Two-Phase Flow in Small Diameter Vertical Conduits"
Hagedorn, A.R. and Brown, K.E., JPT, pp. 475-484 (April, 1965).
Orkiszewski SPE 1546
"Predicting Two-Phase Pressure Drop in Vertical Pipes"
J. Orkiszewski, ESSO Production Research Co., SPE JPT (June 1967), 829-838.
Poettman & Carpenter
"The Multiphase Flow of Gas, Oil and Water Throuh Vertical Flow Strings with Application to the Design of Gas-Lift Installations"
Poettman, F. H., and Carpenter, P. G., API Drilling and Production Practices, 257-317 (1952).
Petalas & Aziz
"Development and Testing of a New Mechanistic Model for Multiphase Flow in Pipes"
Petalas, N. and Aziz, K., proceedings ASME, Fluid Eng. Division, 236, No. 1, pp. 153-159 (1996).