An EOS model for EOR applications was developed for a Kuwaiti reservoir fluid and a CO2 rich injection gas. The project comprised QC of the available sampling and laboratory information, C7+ characterization, and regression to experimental routine PVT and EOR data (incl. Swelling Test, Equilibrium Contact, Multiple Contact, and Slim Tube). The resulting EOS model was used to generate input files to Eclipse Compositional and VIP Comp.
Five reservoir fluids and accompanying PVT data were quality checked and a fluid column analysis performed for two of the fluids, which were sampled in different depths in the same well. Depth gradient simulations revealed that fluid communication did exist. A common EOS model was developed for all five fluids and used for generation of Eclipse Compositional input files.
After a successful quality checking of the seven reservoir fluids a depth gradient study was carried out to reveal possible communication between the sample locations. As no communication was found to exist, separate EOS models were developed for each of the seven reservoir fluids. The PVT data being matched included classical PVT data as well as EOR data measured for a CO2 rich injection gas. The EOR data comprised Swelling Tests, Multiple Contact, Equilibrium Contact, and Slim Tube experiments.
Developed 9 component EOR EOS model for Middle East reservoir fluid with extensive PVT data including swelling, multi contact, equilibrium contact and slim tube data with two different injections gases (CO2 and hydrocarbon).
Four reservoir fluids from one field were previously characterized to the same pseudo components in a 9-component model to be used in compositional simulations. It was difficult to obtain similar match of PVT data (esp., separator GORs) with the 9 component model compared with the 23 component model. A lumping sensitivity study was then performed to investigate the cause of deviations between simulated and measured separator GORs. It was found one of the fluids had very different plus properties than the other three fluids. Therefore, the average properties of the very heavy C7+ pseudo components for four different fluids in the common EOS could not be well represented by less detailed description of the heavy end specified in the original lumping scheme. This resulted in the poor match of separator GORs. It was concluded the lumping scheme for the 9 component model could be changed to improve the match of separator GORs. A new EOS model with a different lumping scheme of 11 components (by splitting one C20+ pseudo component into 3 components) was developed which gave a better match of the separator GORs while keeping a good match of other PVT data for all the fluids.
Two EOS models were developed for a Middle East reservoir fluid. One was for use in Eclipse Comp simulations and the other one for generation of Eclipse Black Oil tables. Since compositional reservoir simulations are time consuming, the former model had the components heavily lumped. Each EOS model was developed to match classical PVT and EOR data. The EOR data comprised Swelling Tests and Slim Tube experiments and were performed using two injection gases; pure CO2 and a light natural gas.
Two reservoir fluids were to be described using a common EOS model. Two models with different degrees of component lumping were developed. One model to be used in Eclipse Compositional had the components heavily lumped. A second model with less heavily lumped components was used to generate Eclipse Black Oil input tables. A variety of PVT data was matched including Saturation Point, Separator Test, CVD, CME, and Viscosity. Slim tube and MMP simulations were carried out to decide whether a miscible could be achieved through gas injection.
A common EOS was developed for four fluid samples from a North Sea field. The project comprised a QC of the available sampling and laboratory information, cleaning of OBM contaminate, characterization, and regression to experimental routine PVT data including viscosity experiments. The resulting EOS model was used to generate input files to Eclipse Black Oil.
Three EOS models were created for reservoir fluids from three reservoirs A (4 fluids), B (3 fluids) and C (1 fluid), respectively, for later use in a compositional reservoir simulation study. These fluids varied from oil, volatile oil, retrograde condensate, to gas condensate. Fluids from the same field were characterized to same pseudo components. The EOS models were tuned to obtain a good match of experimental PVT data. The tuned fluids were then used to generate input files for further simulations in Eclipse 300.
Gas lift injections were considered for productions of two oils. Both oil samples were contaminated with OBM. They were first cleaned for OBM and then characterized to the same pseudo components.
Characterization study for 12 different fluids, varying from lean condensates to oils with API<25. All fluids were characterized to same pseudo components and matched experimental PVT data for the individual fluids.
A common EOS model was previously created for 19 reservoir fluids from Field A. There were another 13 fluids from Field A and 3 fluids from Field B comingled in production. It was desired to apply the same EOS model to the 16 new reservoir fluids and then assign different names for the same pseudo components to distinguish fluids coming from Field A and Field B for allocation purposes. The phase behavior for each new fluid was also verified against its experimental PVT data.
Characterization to same pseudo components for 5 fluids from GOM field. The fluids varied from gas condensates to black oils and all samples were contaminated with mud. The resulting EOS model matched experimental data for all fluids and was lumped to 6 components.
EOS model for North Sea chalk reservoir fluids flooded with CO2. Critical point on swelling curve and liquid dropout curves for near-critical fluid compositions matched.
Based on pressure gradient data and bottom hole samples from 4 different zones, it was evaluated whether an EOS model for depth gradients would support communication between the zones.
Based on bottom hole samples from 9 different wells, the amount of wax deposition was evaluated in a pipeline that would transport the co-mingled fluid from the wells.
An EOS model had been developed some years in advance for a field in the Middle East. The field was reach in H2S with large horizontal variations in H2S concentration. CO2 injection was planned to take place. The task was to evaluate the quality of the EOS model and to find out how well the EOS description matched more recent PVT data including CO2 swelling data.
EOS models were developed for 16 separator gases from 14 different North Sea fields, most of which were to be let to the same process plant. Cricondenbars, and C2+-contents were projected of the future gas deliveries to the process plant.
PVT reports for a field in Africa covering a period of around 25 years were evaluated and compared. In this evaluation the production from the field during the 25 years of production was to be taken into consideration. The purpose of the project was to provide a best estimate of the composition of the currently produced reservoir fluid and to generate corresponding Eclipse black oil input PVT tables.
The potential for asphaltene precipitation in a Venezuelan field was evaluated. Various production strategies were considered including natural depletion, natural gas injection and CO2 injection. It was found that each of these production strategies might lead to severe asphaltene precipitation problems.
Twelve different well streams from a North Sea reservoir were characterized to a unique set of 7-8 pseudo components. The compositions covered gas condensates, near critical fluids and oil compositions. The reservoir pressures were of the order 900 bar. PVT data for each of the 12 fluids was matched and Eclipse Comp files generated for each stream.
Developed regression procedure performing fluid characterization and regression in same operation. Published in Journal of Canadian Petroleum Technology.
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