There has been a large gap in the modeling and understanding of reservoir fluids; this deficiency has led to major inefficiencies in field development planning. Petroleum system modeling provides the timing, type and volume of fluids entering the reservoir (among other things). However, reservoir fluid compositional redistributions and phase changes during and post charge to present day have been underappreciated. Nevertheless, these in-reservoir fluid redistributions and tar formation can impact production in major ways. A new technical discipline resolves this concern; “Reservoir Fluid Geodynamics” (RFG)which is treated in detail in the new book “Reservoir Fluid Geodynamics and Reservoir Evaluation” authored by the speaker. RFG provides the 1st-principles description of the dynamics of reservoir fluids in geologic time. Key enabling advances include: 1) asphaltene thermodynamics to address evolution of reservoir fluids over geologic time, 2) wireline Downhole Fluid Analysis (DFA) providing measurements of reservoir fluid gradients that are key for thermodynamic evaluation, and 3) 70 oilfield case studies treated within an RFG construct. RFG is fundamentally a thermodynamic approach and is complemented very well by geochemistry. The first successful application of RFG is the now ubiquitous practice of examining reservoir connectivity via DFA-measured asphaltene equilibration; this approach is shown to work for light oils, black oils and heavy oils. The role of maturity variation in a simple charge is shown. RFG studies are revealing the sequence of events in multiple charging of reservoirs with fault block migration. Gas charge into oil with concomitant tar mat formation is shown. Viscosity gradients especially in heavy oil are treated from a thermodynamic perspective; one reservoir study shows an excellent match withno adjustable parametersof a heavy oil column with a 10x gradient of asphaltenes (and 1000x gradient in viscosity) over a 100 kilometer rim of a 4-way sealing anticline. Biodegradation can result in large in-reservoir gradients at and near the OWC, large in-reservoir gradients at the top of the column, or small in-reservoir gradients depending on the specifics of the RFG processes as shown in multiple case studies. Reservoir fluid geodynamics is finally enabled, is easy to employ using a ‘universal workflow’ and greatly improves reservoir evaluation.
Bio: Dr. Oliver C. Mullins is a Schlumberger Fellow and member, U.S. National Academy of Engineering. He is leading the new discipline, “reservoir fluid geodynamics” (RFG), which accounts for fluid compositional redistribution and phase change during and post charge over geologic time. RFG is focused on reservoir evaluation and utilizes Downhole Fluid Analysis which he initiated and asphaltene thermodynamics which his team developed. He wrote 2 books, coauthored ~300 other publications and coinvented 138 allowed US patents with 24,000 citations on google scholar. He has received six international awards four organizations (ACS, SPE, SPWLA, ADIPEC) including the George A. Olah Award from the American Chemical Society and the 2021 Anthony F. Lucas Gold Medal.