Shallow, Unconsolidated Sandstone Heavy Oil Reservoirs
Reservoir Evaluation, Sand Management, and EOR for the World's Shallow Heavy-Oil Sands
Assign your company's shallow, unconsolidated sandstone heavy oil reservoir evaluation and development challenges to A&A, and let the high-level, seasoned thermal, polymer, sand-management, and geomechanics consultants of the A&A Consulting Team apply decades of combined experience to your reservoirs, in Venezuela and around the world.
Avasthi & Associates, Inc. (A&A) is an independent petroleum engineering consulting firm. A&A does not sell sand-control equipment, steam-generation equipment, polymers, or reservoir-simulation software — our only business is expert technical consulting, which means our recommendations for these reservoirs are never influenced by a stake in any particular vendor or technology.
Numerous regions worldwide host shallow, unconsolidated (to poorly/weakly consolidated) sandstone reservoirs containing heavy oil, typically occurring at depths ranging from approximately 40 to 1,200 meters (131 to 3,940 feet). These reservoirs are estimated to contain billions of barrels of heavy oil, characterized by API gravities between 8° and 22° and viscosities reaching up to 10,000–50,000+ centipoise (cP) under reservoir conditions. The hydrocarbons are commonly found within high-porosity sandstone formations, often exceeding 30%.
The high viscosity, combined with potential foamy-oil behavior, makes these reservoirs a target for enhanced oil recovery (EOR) techniques, such as Cyclic Steam Stimulation (CSS) and steamflooding, as well as polymer flooding, designed to manage high-viscosity oil. Because the reservoir sand itself is unconsolidated, sand production, wellbore stability, and completion design are just as central to developing these reservoirs as the EOR method chosen.
The A&A Consulting Team of high-level, seasoned thermal EOR, polymer EOR, sand-management, and geomechanics consultants has significant expertise and practical knowledge in applying all types of evaluation and recovery techniques required to develop, and enhance oil recovery from, these types of heavy oil fields.
Venezuela's Orinoco Belt, and Other Global Analogs
Venezuela's Faja Petrolífera del Orinoco (Orinoco Belt) is among the world's largest, and best-documented, examples of shallow, unconsolidated heavy-oil sands: published reservoir data for the Faja describe reservoir depths of roughly 1,700 to 2,350 feet (520 to 720 meters), porosities of 30% to 35%, unconsolidated sand character, and oil gravities as low as 7° to 10° API — extra-heavy oil, by the World Energy Council's classification.
Other globally significant shallow, unconsolidated sandstone heavy-oil developments include Cold Lake, in Alberta, Canada; the Duri field, in Sumatra, Indonesia — one of the world's largest steamflood projects, in reservoir sands only 250 to 800 feet deep; and California's Kern River and Midway-Sunset fields. A&A's thermal and polymer EOR consultants have experience evaluating and developing heavy oil reservoirs of this type, in these and other basins, around the world.
Related A&A Service: For A&A's full CSS, steamflood, and SAGD technical services — including detailed Venezuela heavy oil and extra-heavy oil resource context — please see A&A's Heavy Oil Resources Evaluation, Development and Optimization page.
Reservoir Evaluation and EOR Screening
Our consultants conduct comprehensive reservoir and fluids evaluation studies, to determine whether — and how — a shallow, unconsolidated sandstone heavy oil reservoir can be economically developed, including, but not limited to:
• Original oil in place (OOIP) and mobile-oil estimation
• Heavy-oil PVT and viscosity-temperature characterization
• Foamy-oil behavior assessment, and its effect on primary-recovery forecasts
• Porosity, permeability, and reservoir heterogeneity characterization, in unconsolidated sand
• Net-pay mapping, and identification of shale barriers and thief zones
• Rock-fluid interaction and wettability analysis
• Candidate screening across cold production, CSS, steamflood, SAGD, and polymer flooding, based on reservoir depth, viscosity, and sand consolidation
Sand Management and Wellbore Stability
Because these reservoirs are unconsolidated, or only weakly consolidated, sand production and wellbore stability are central to developing them safely and economically — regardless of which recovery method is ultimately selected. Our consultants provide, including, but not limited to:
• Geomechanical modeling and in-situ stress analysis for unconsolidated sand formations
• Sand-production prediction, and design of sand-control completions (gravel packs, frac packs, and sand screens)
• Wellbore-stability analysis, to reduce drilling and completion costs
• Wormhole-network characterization, for cold-production and post-cold-production EOR candidates
Related A&A Service: For A&A's full geomechanics, sand-production-prediction, and wellbore-stability consulting services, please see A&A's Geomechanics Consulting page.
Cold Heavy Oil Production with Sand (CHOPS), and Foamy-Oil Drive
Many shallow, unconsolidated sandstone heavy oil reservoirs are first produced through cold heavy oil production with sand (CHOPS) — deliberately co-producing formation sand, using horizontal wells and progressive-cavity or other sand-tolerant pumps, to create high-permeability wormhole networks that can substantially increase primary recovery, particularly where foamy-oil drive is present. Our consultants provide, including, but not limited to:
• CHOPS candidate screening, and forecasting of primary-recovery uplift from wormhole development
• Artificial-lift design and evaluation for sand-tolerant, high-viscosity production
• Post-CHOPS EOR candidate screening, for reservoirs already produced under cold production
Related A&A Service: For A&A's full artificial-lift, sand-control, and production-optimization services, please see A&A's Production Optimization page.
Thermal EOR: CSS, Steamflood, and SAGD
For reservoirs where thermal recovery is favored — typically deeper, higher-viscosity, and thicker-pay candidates within this reservoir class — our thermal EOR consultants conduct the full range of CSS, steamflood, and SAGD screening, design, simulation, and field-surveillance services.
Related A&A Service: For A&A's full thermal EOR technical service list, please see A&A's Heavy Oil Resources Evaluation, Development and Optimization page.
Polymer Flooding for Viscosity Management
For reservoirs where polymer flooding is a better fit than thermal recovery — typically shallower, lower-temperature-tolerant candidates within this reservoir class — our polymer EOR consultants conduct the full range of polymer EOR screening, laboratory-test simulation, and field design and forecasting services.
Related A&A Service: For A&A's full chemical/polymer EOR technical service list, please see A&A's Chemical/Polymer EOR Consulting page.
What A&A Delivers
A shallow, unconsolidated sandstone heavy oil reservoir engagement with the A&A Consulting Team is built around the practical decisions your company needs to make, including, but not limited to:
• A recommended development strategy: cold production (CHOPS), CSS, steamflood, SAGD, or polymer flooding, matched to your reservoir's depth, viscosity, and sand consolidation
• Sand-control and wellbore-stability recommendations: to develop the reservoir safely and economically
• OOIP, mobile-oil, and recovery-factor estimates supporting your field development planning (FDP) and investment decisions
• Presentation-ready recommendations for your company's management, partners, and investors
To discover how the A&A Consulting Team of high-level, seasoned consultants can assist your company in developing shallow, unconsolidated sandstone heavy oil reservoirs, in Venezuela and around the world, please click here.
