Moreno Ortiz, Jaime Eduardo (Schlumberger) | Gossuin, Jean (Schlumberger) | Liu, Yunlong (Schlumberger) | Klemin, Denis (Schlumberger) | Gurpinar, Omer (Schlumberger) | Gheneim Herrera, Thaer (Schlumberger)
Challenges on EOR process upscaling have been discussed extensively in the industry and effects of diffusion, dispersion, heterogeneity, force balance and frontal velocity -among others, recognized and qualified, along with the importance of understanding the numerical model finite difference equations and modeling strategy. Augmenting the upscaling complexity is the often-limited understanding/data on the EOR displacement at different scales (from micro to full field), including the EOR agent/rock/fluid interactions that is often available at the early stages of the EOR process de-risking.
A common denominator for the EOR process characterization and upscaling (along with the discretization of the displacement) is the non-uniqueness nature of the problem. As the complexity of numerical representation of the EOR process increases (thus increasing data characterization requirements), so does the number of plausible solutions and challenges when dealing with an otherwise incomplete dataset. Digital rock has evolved as a strong alternative to complement laboratory corefloods, allowing for EOR agent optimization on a high-resolution digital representation of the pore structure, detailed digital fluid model of both reservoir fluids and EOR agents and physical rock-EOR agent-reservoir fluid interaction, thus providing several calibration points to ensure the finite-difference model calibration and upscaling preserve the process behavior.
This paper discusses the use of digital rock solutions on the EOR deployment, particularly on translating the results to numerical finite difference models, addressing the inherent laboratory measurement uncertainty and proposing a fit-for-purpose multi-scale upscaling strategy that addresses both effects of heterogeneity and EOR agent characterization during the upscale process.
This paper addresses the challenges of chemical flooding upscaling, particularly polymer by using a real-life polymer injection case where digital rock, corefloods and more importantly pilot results are available to test and validate our observations. Using a polymer coreflood and digital rock results as input, numerical finite difference simulation models were built and calibrated to effectively reproduce the displacement physics observed on both digital rock and corefloods, digital flood results were used to bridge the laboratory-to-numerical model step by providing effective upscaled polymer properties as well as intrinsic rock properties such as relative permeability and capillary pressures, which are then taken through a series of multi-scale finite difference models to identify, validate and quantify upscaling requirements, addressing polymer deformation through pore throats and effective simulation viscosity. Digital rock is used to rank and resolve ambiguity on the finite difference model calibration by providing an otherwise rare opportunity to visualize the displacement in the 3D space. The analysis shed a new light on fluid-fluid and fluid-rock interaction at pore scale and enabled us to improve on the finite difference model generation and polymer properties.
Polymer enhanced oil recovery (EOR) has been successful in onshore and offshore reservoirs, and is especially promising for heavy oil or heterogeneous reservoirs. Polymer retention, mainly due to adsorption, results in the removal of polymer from the solution, leading to the formation of a polymer-free bank. Thus, determining the retention is a key factor in evaluating the feasibility of polymer flooding. This work investigates a method to reduce polymer adsorption and improve the economics of polymer EOR. This is done through laboratory experiments and reservoir simulation. The experimental investigations consisted of five dynamic retention core floodings in fresh and non-fresh high permeability sandstones. Five concentrations of a HPAM-AMPS in high salinity brine were tested. Two types of experiments were performed: fresh-adsorption, and re-adsorption. Injection of the polymer solution in porous media that had never been in contact with polymer composed the fresh-adsorption experiments. Differently, the re-adsorption experiments were performed in media that had been flushed with the same polymer previously. The experiments indicated a type IV isotherm for fresh-adsorption, while the re-adsorption isotherm was of type I. For a polymer concentration of 1250ppm, the fresh-adsorption was 166.7μg/g while the cumulative re-adsorption was 64.8μg/g. Therefore, reduction of ∼61% may be achieved by pre-flushing the medium with a low polymer concentration solution before the injection of the mobility control bank. Other properties of the polymeric system were measured in the core floodings to serve as inputs to the reservoir simulation model. The field-scale simulation studies evaluated the economic impact of the injection of a low concentration polymer slug to reduce polymer loss during EOR, such as observed in the re-adsorption experiments. The production strategy optimization was composed of eight steps, and targeted net present value (NPV) maximization. The case studied was a heavy oil offshore sandstone field, based on a benchmark. The strategy to reduce polymer retention represented a 4% increase in the final NPV over the conventional polymer flooding. Additionally, risk curve analysis demonstrated the advantage of this reduced-retention strategy over waterflooding and conventional polymer flooding. This work shows experimental evidence that polymer overall retention may be reduced through injection of a low polymer concentration bank prior to the mobility control one. Additionally, through numerical simulation and economic analysis, it indicates that the reduced retention allows for an economic advantage in polymer EOR, which may improve the feasibility of polymer flooding projects.
Asia Pacific Santos discovered gas with the Corvus-2 well in the Carnarvon Basin, offshore Western Australia. The well, located in permit WA-45-R, in which Santos has a 100% interest, reached a total depth of 3998 m. It intersected a gross interval of 638 m, one of the largest columns discovered across the North West Shelf. Wireline logging to date has confirmed 245 m of net hydrocarbon pay across the target reservoirs. Total SA and partners ExxonMobil and Oil Search have signed a gas agreement with the government of Papua New Guinea that defines the fiscal framework for the Papua LNG project in the country's Eastern Highlands. The plan involves construction of three 2.7-mtpa LNG trains on the existing PNG-LNG plant site at Caution Bay just west of Port Moresby. Total has 31.1% interest, ExxonMobil has 28.3% interest, and Oil Search has 17.7%.
ExxonMobil’s hot streak of offshore discoveries have sparked investor interest in the Guyana-Suriname basin. How did the company get there, and why do industry representatives feel optimistic about future deepwater prospects in the region? In the 30 years of operations on Suriname’s Tambaredjo field, the prime mechanism for lifting the 15.6 °API crude to surface has been that of progressing cavity pumps (PCPs).
Moving their directional drillers into their Houston real-time remote operations centers has improved drilling efficiency for two of the top shale producers. The major’s dominant showing in US Gulf of Mexico Lease Sale 252 propelled another rise in bids and dollars for the biannual regionwide auction. Funding for startups in the upstream industry does not always guarantee that oil and gas companies will want to test the new technology. A new venture and accelerator model hopes to change this through guaranteed pilots. The Pluma-1 discovery could turn the southeast portion of Stabroek Block off Guyana "into a major new development area," the company says.
Learn more about training courses being offered. Learn more about training courses being offered. This course covers the fundamental principles concerning how hydraulic fracturing treatments can be used to stimulate oil and gas wells. It includes discussions on how to select wells for stimulation, what controls fracture propagation, fracture width, etc., how to develop data sets, and how to calculate fracture dimensions. The course also covers information concerning fracturing fluids, propping agents, and how to design and pump successful fracturing treatments. Learn more about training courses being offered. Current and future SPE Section and Student Chapter leaders are invited to engage and share. Every attendee leaves energised with a full list of ideas and a support network of fellow leaders. Those sections and student chapters actively participating in this workshop have consistently been recognized with awards as the best in SPE. SPE Cares is a global volunteering drive aimed at promoting, supporting and participating in community services at the SPE section and student chapter’s level. On its official launch this year at ATCE Dubai, SPE Cares will conduct a “Give a Ghaf” Tree Planting Programme to help preserve Ghaf’s cultural and ecological heritage. The Ghaf tree is an indigenous species, specific to UAE, Oman and Saudi Arabia. It is a drought tolerant, evergreen tree that can survive a harsh desert environment. The initiative not only aims to hold events/activities at ATCE, but also recognise community service that SPE members are already conducting in their respective student chapters and professional sections. The KEY Club, open daily, is an exclusive lounge for key SPE members. The lounge is open to those with 25 years or more of continuous membership, Century Club members, current and former SPE Board officers and directors, Honorary and Distinguished Members, as well as this year’s SPE International Award Winners and Distinguished Lecturers. DSATS (SPE’s Drilling Systems Automation Technical Section) will hold a half-day symposium featuring keynote presentations on urban automation. This symposium will explore technologies being used in developing smart cities through the automation of their infrastructure, transportation systems, energy distribution, water systems, street lighting, refuse collection, etc. These efforts rely on many of the same tools needed for drilling systems automation yielding increased efficiencies, lower maintenance and reduced emissions. Their knowledge and experience can guide the path being travelled by the oilfield drilling industry.
Production from the Hibernia platform was shut down again on 17 August after its second oil spill in a month, while Husky Energy began to ramp up output from the White Rose field following the largest-ever spill off Canada’s easternmost province. The deal consists of stakes in nine shallow-water producing fields covering 108,000 gross acres in 10–50 m of water. Up to 55,000 BOE/D of output is expected from the ExxonMobil-operated Bajo del Choique-La Invernada block in the Argentine shale play, with a possible second phase producing up to 75,000 BOE/D. Expected to start up in mid-2022, Liza Phase 2 will produce up to 220,000 B/D of oil. Yellowtail-1 is the fifth discovery in the Turbot area, where ExxonMobil plans another Stabroek Block development hub.
The discovery marks London-based Tullow’s first operated contribution to a long list of discoveries since 2015 in the emerging petroleum province. Expected to start up in mid-2022, Liza Phase 2 will produce up to 220,000 B/D of oil. Could 2019 be a bumper year for offshore energy development? Yellowtail-1 is the fifth discovery in the Turbot area, where ExxonMobil plans another Stabroek Block development hub. Conventional oil and gas discovered resources in 2019 are on pace to rise 30% from last year and reach their highest level since the beginning of the industry downturn.
Application of polymer flooding as a chemical Enhanced Oil Recovery (EOR) has increased over recent years. The main type of polymer used is partially hydrolyzed polyacrylamide (HPAM). This polymer still has some challenges especially with shear stability and injectivity that restrict its utility, particularly for low permeability reservoirs. Injectivity limits the possible gain by acceleration in oil production due to polymer flooding. Hence, good polymer injectivity is a requirement for the success of the operation. This paper aims to investigate the influence of formation permeability on polymer flow in porous media.
In this study, a combination of core flooding with rheological studies is presented to evaluate the influence of permeability on polymer in-situ rheology behavior. The in-situ flow of HPAM polymers has also been studied for different molecular weights. The effect of polymer preconditioning prior to injection was studied through exposing polymer solutions to different extent of mechanical degradation.
Results from this study reveal that the expected shear thinning behavior of HPAM that is observed in rheometer measurements is not observed in in-situ rheology in porous media. Instead, HPAM in porous media exhibits near-Newtonian behavior at low flow rates representative of velocities deep in the reservoir, while exhibiting shear thickening behavior at high flow rates representative of velocities near wellbore region. The pressure build-up associated with shear thickening behavior during polymer injection is significantly higher than pressure differential during water injection. The extent of shear thickening is high during the injection of high Mw polymer regardless of cores' permeability. In low permeable Berea cores, shear thickening and mechanical degradation occur at lower velocities although the degree of shear thickening is lower in Berea to that observed in high permeable Bentheimer cores. This is ascribed to high polymer retention in Berea cores that results in high residual resistance factor (RRF). Results show that preshearing polymer before injection into porous media optimizes its injectability and transportability through porous media. The effect of preshearing becomes favorable for the injection of high Mw polymers into low permeability formation.
This study discusses polymer in-situ rheology and injectivity, which is a key issue in the design of polymer flood projects. The results provide beneficial information on optimizing polymer injectivity, in particular, for low permeability porous media.
Foam-Assisted Surfactant Flooding (FASF) is a novel enhanced oil recovery (EOR) method combining the reduction of oil-water (o/w) interfacial tension (IFT) to ultra-low values and foaming of a gas drive for mobility control. We present a detailed laboratory study on the FASF process at reservoir conditions. The stability of two specially selected surfactants in the vicinity of original injection water, i.e. sea water, at 90°C was assessed. The phase behaviour of the crude oil-surfactant-brine systems and the ability of the two selected surfactants to generate stable foam in bulk were studied in presence and in absence of crude oil. The phase behaviour and bulk tests resulted in the formulations of the surfactant slug and drive solutions. The slug solution aims for oil mobilisation by lowering of the o/w IFT and the drive formulation is required for gas foaming for mobility control. CT scanned core-flood experiments were conducted in Bentheimer sandstone cores initially brought to residual oil by water flooding. Oil mobilisation was obtained by injecting a surfactant slug at either under-optimum (o/w IFT of 10-2 mN/m) or optimum (o/w IFT of 10-3 mN/m) salinity conditions. At both salinities the injected surfactant slug yielded the formation of an unstable oil bank due to dominant gravitational forces. Optimum salinity surfactant slug was notably more effective at reducing residual oil to waterflood (81% reduction) compared to the under-optimum salinity slug (30% reduction). After oil mobilisation, drive foam was either generated in-situ by co-injection with nitrogen gas or was pre-generated ex-situ and then injected to displace mobilised oil. It was found that, at optimum salinity, FASF yielded an ultimate recovery factor of 40±5% of the oil in place (