Modelling reservoir depletion processes to obtain more representative oil formation volume factors

Abstract

This research investigates the way laboratory oil formation volume factors (FVF or 𝐵𝑜) from differential liberation (DL) and flash separation tests are used by engineers to represent real reservoir production processes. The work proposes standardization in these approaches, including a way of adjusting laboratory DL data to represent a true differential process and develops a new technique for obtaining composite 𝐵𝑜 data from combined DL and separator tests. The research consists of the following work:  survey of the oil industry, mainly focusing on UAE engineers  developing a procedure to correct experimental 𝐵𝑜 data o quality checking of hydrocarbon PVT data and tuning the equation of state o simulating the infinite-step DL test to correct laboratory differential Bo to a true differential process o simulating the composite test which is a combination of DL and separator tests to calculate composite 𝐵𝑜  computer laboratory work, modelling 3-D reservoir black-oil and compositional models to calculate 𝐵𝑜 and explore which processes ECLIPSE 100 and ECLIPSE 300 are mimicking The study shows that the standard PVT studies are designed to model the hydrocarbon fluid flow from the porous media to the surface, but the sequence of processes carried out in XVIII the laboratory can’t represent real reservoir production processes. The analysis of laboratory DL studies demonstrates that these can seriously overestimate true differential processes. Based on the work above, a novel infinite-step differential method and a new EOS composite method have been developed to correct experimental data and obtain the most accurate fluid property, 𝐵𝑜 values as a function of the reservoir pressure, and thus better match the field operating processes than previous methods investigated. This work shows that laboratory FVF data are commonly misunderstood by industry engineers and recommends greater awareness and better education. The method developed here could be used as part of a guideline to allow most engineers to obtain representative 𝐵𝑜 values. In the reservoir simulator tested calculation, the output 𝐵𝑜 obtained from the black-oil model is entirely dependent on the input 𝐵𝑜. The calculated 𝐵𝑜 from the compositional model matches very well with the new EOS composite 𝐵𝑜.

Date of Award	2015
Original language	American English
Supervisor	John Williams (Supervisor)