Objective
The object of this project is to develop suitable methods for the determination of oil/gas/water relative permeabilities under reservoir conditions in the laboratory. The relative permeability data is of great importance in the planning stage as well as the production development of secondary (waterflooding) and tertiary (chemical flooding, as drive, steam injection etc.) recovery projects. The reservoir behaviour is simulated with a computer model which depends heavily on reasonable input data including oil/water/gas relative permeabilities. It is expected that measurements under simulated reservoir(pT-) conditions yield more meaningful results and will improve the reservoir engineering calculations. Of innovative character will be the installation of a system that continuously monitors the saturation conditions in the core sample during linear water/oil displacement experiments under reservoir conditions and the development of a computer programme creating analytical
Experimentation with the small-scale flooding apparatus resulted in the selection of an unsteady state method (linear displacement) for the determination of oil/water relative permeabilities and a steady state procedure for the determination of gas/water relative permeabilities. The monitoring system for the saturation conditions in the core sample which consists of two plate electrodes at the core faces and four ring electrodes distributed along the core sample produced good results for reservoir sandstones with low clay contents ( 3 %). The migration of a saturation discontinuity through the core sample could be observed and the impedance data evaluated with respect to average water saturation in the entire core as well as in the three segments between the ring electrodes. The measuring device for the determination of produced oil, water, and gas when flooding with recombined reservoir oil consists of a separator tank and a gas flowmeter. This device was used for checking the saturation data evaluated from the impedance measurements. Two experiments using dead crude oil have been performed uner pT-conditions of 200 bar/50 deg. with pore pressures ranging from 30 - 50 bar. Two further experiments were carried out with gas-recombined crude oil according to the reservoir conditions of an oilfield in the East Hanover province.
The project comprises five stages:
1. Design and construction of a small-scale installation for linear flooding experiments on sandstone plugs (3 cm diameter and 5 cm length)
2. Determination of oil/water relative permeabilities with the small flooding installation. The suitable procedures will afterwards be employed on PREUSSAG's high-pressure autoclave.
3. Reconstruction of the high-pressure autoclave for flooding experiments with reservoir oil.
4. Measurement of oil/water and gas/water relative permeabilities under reservoir conditions of an oil reservoir from the Osthannover area and a gas reservoir from the Ostfriesland area.
5. Evaluation and interpretation of the collected data.
During the first stage of the project a small flooding installation is designed and built in order to screen the suitable methods available for relative permeability evaluation. This will save time and cost because only successfully tested methods will be used for PREUSSAG's high-pressure autoclave.
The second stage includes the testing program for the small flooding installation. Oil/water relative permeability will be evaluated from linear flooding experiments and gas/water relative permeability measurements from steady-stade flooding experiments. Hereby the average oil/water/gas saturations in the core will be determined by electrical resistivity measurements.
The third stage will be the implementation of the selected methods on the high-pressure autoclave. This requires the installation of pressure vessels for reservoir oil and a separator at the autoclave exit.
In the fourth stage the high-pressure autoclave is put into operation for oil/gas/water relative permeability measurements under reservoir conditions simulating real reservoir parameters such as temperature, pore pressure, overburden pressure, viscosity of fluids, etc...
Finally, the collected data is evaluated with respect to relative permeability as a function of reservoir parameters. The results are presentedin a commented graphical and tabulated form. They will also be published in respective journals and presented at appropriate conferences.
Programme(s)
Topic(s)
Call for proposal
Data not availableFunding Scheme
DEM - Demonstration contractsCoordinator
1000 Berlin
Germany