Wireline Formation and Reservoir Testing

Current Course Schedule:

Objective:

This course has been developed for geologists, reservoir engineers and other petroleum technologists who are interested in the application of logging and distributed pressure measurements to enhance their understanding of the relationship between the geological model and the actual reservoir behavior.

Course Description:

The course examines the application of wireline formation tester (WFT) distributed pressure data in appraisal (unproduced field) and development (produced field) wells.  In addition the determination of permeability, horizontal and vertical, using new generation, pump-out tools is addressed fully.  Finally an extensive coverage of the sampling aspects of the new generation tools is given.  Software packages for analyzing data will be utilized in conjunction with field examples.

Course Contents:

1. Distributed  Pressure  Measurement (DPM)
• Wireline formation testers (WFT), new generation WFT (NGWFT), pretest, supercharging mechanism, time of observable buildup, supercharging index (SI)
2. Exploration Applications of DPM
   • Gravity-capillary equilibrium, pressure-depth diagrams, effect of a residual oil saturation, paleocontacts, oil wet behavior, field examples, forced gradient technique, multiple well analysis, detection of gas and water oil contacts, compositional reservoirs, perched contacts and isolated water, naturally fractured reservoirs, dynamic aquifers and tilted contacts, field examples of such effects, over pressured reservoirs, SEC attitude to NGWFT
3. Field Development Applications of DPM
   • Fields under production, introductory field examples, supercharging diagnosis, single phase flow, uniform vertical permeability, fictional (Darcy) component of pressure gradient, vertical pressure equilibrium, barrier detection, semi-steady-state differential depletion, compartmentalized material balance, interpretation through reservoir simulation, two-phase flow, interpretation of observed pressure gradients, vertical saturation equilibrium, counter-current two-phase flow, gravity drainage, percolation, co-current upward two-phase flow, accuracy in gradient determination, WFT interpretation for reservoir description, dual porosity strata example, parabolic pressure profiles, early field examples from North Sea reservoirs, Etive-Rannoch problem, partially communicating faults, high slant wells, potential versus true horizontal length diagrams
4. Permeability from WFT and NGWFT
   • Pretest permeability, spherical flow, steady-state draw down behavior, Stewart and Wittman flow shape factor, finite element modeling, buildup permeability, tandem reciprocal root of time plot, extrapolation to local pressure, pump-out systems, straddle packer arrangement, limited entry model, mini-dsts, problem of thickness estimate, depth of investigation, value of information (voi) analysis, potential to replace conventional dst, impulse tests, prefrac testing in tight reservoirs, vertical observation probe, analytical model from Carslaw and Jaeger, derivative response of vertical interference test, parameter estimation from specialist plots and nonlinear regression, combined sum of squares, interference buildup response, time delay to pressure reversal at observation point, derivative “spikes”, active probe response, effect of anisotropy, calibration of analytical model with FEM simulation, slant well situations, field examples of interference tests.
5. Sampling
   • Dynamics of mud filtrate invasion, near wellbore saturation profile, simulation of pump-out process,  downhole fluid analysis, optical spectroscopy, contamination of sample, real time monitoring, downhole fluid density and viscosity measurement, prediction of fluid producing cgr or gor,  compositional reservoirs, variation of bubble and dew point through the hydrocarbon column, intelligent sampling beneath a shale, guard ring sampling, importance for reserve estimation, detection of compartmentalization, fluid finger printing.
6. Capillary Pressure Effect
   • Simulation of the invasion process, pressure and saturation profiles, capillary transition zones, shifting of hydrocarbon fluid pressure with water based mud, field examples from Pakistan and Middle East, Shell technique for detecting a shift, tentative oil wet field example, effect of oil-based mud on water phase pressure, North Sea field examples, Halford field example, implication for reserve estimates and unitization.
7. Integration with Production Logging
   • History matching of layered reservoir simulators, differential depletion, compartmentalized material balance models, adjustment of layer skin factors to force agreement with production logging, determination of distributed pressure in existing development wells, selective inflow performance.
8. Review of Selected SPE and SPWLA Key Papers
9. Demonstration of Pressure-Depth Plotting Software
10. Demonstration of Pressure Transient Analysis Software for NGWFT (PanSystem)