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Collaborating Authors
Permian Basin
Use of Horizontal Injectors for Improving Injectivity and Conformance in Polymer Floods
Hwang, Jongsoo (The University of Texas Austin) | Zheng, Shuang (The University of Texas Austin) | Sharma, Mukul (The University of Texas Austin) | Chiotoroiu, Maria-Magdalena (OMV Exploration & Production GmbH) | Clemens, Torsten (OMV Exploration & Production GmbH)
Abstract Several field cases have demonstrated polymer injection in a horizontal well increases oil recovery. It is important to maintain high injectivity while preventing injection-induced fractures to ensure good reservoir sweep. Our primary goal in this paper is to better understand polymer injection data from horizontal injectors in the Matzen field using a fully integrated reservoir, geomechanics, and fracturing model. By simulating polymer injection history, we present several advantages of horizontal injectors over the vertical wells. Horizontal injectors delay fracture initiation and provide better tolerance to polymer plugging on the wellbore surface. Simulations explain the measured PLT data of fluid distributions influenced by accumulated polymer deposition in multiple zones. We show that gradual injectivity decline is attributed to both polymer filter cake buildup and high-viscosity, shear-thickening zones created around the wellbore. The field case simulation also clarifies the flow distribution in different sands and how polymer rheology affects this. This distribution is found to be different than for water injection. Results from periodic acid treatments clearly show that free-flowing particles in the polymer solution are responsible for formation damage. Polymer plugging and the viscous pressure drop in the shear-thickening zone are the primary factor affecting the measured injection pressure. Based on the strong near-wellbore viscosity impact, geomechanical simulations identify reservoir zones prone to fracture growth during long-term injection, and we suggest strategies to avoid injection induced fractures that can lead to poor conformance.
- Europe (1.00)
- North America > United States > Alaska (0.28)
- North America > United States > Texas (0.28)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.47)
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Lifecycle > Disposal/Injection (0.51)
- North America > United States > Texas > Permian Basin > Yeso Formation (0.99)
- North America > United States > Texas > Permian Basin > Yates Formation (0.99)
- North America > United States > Texas > Permian Basin > Wolfcamp Formation (0.99)
- (37 more...)
Liquid CO2 EOR Potential in the Illinois Basin: Results of the Mumford Hills Pilot
Okwen, Roland T. (Illinois State Geological Survey, Prairie Research Institute, University of Illinois at Urbana-Champaign) | Frailey, Scott M. (Illinois State Geological Survey, Prairie Research Institute, University of Illinois at Urbana-Champaign)
Abstract Historically, deep oil reservoirs with temperatures and pressures above the critical point of carbon dioxide (CO2) are generally preferred over shallower reservoirs in enhanced oil recovery (EOR) and CO2 storage operations because of high recovery and storage efficiencies associated with miscible floods. As a result, shallower reservoirs containing significant volumes of recoverable resource are generally overlooked. However, basins with relatively low geothermal gradients and high fracture gradients, such as the Illinois Basin, can sustain pressures above the vapor pressure of CO2 where CO2 changes from a gas to liquid. Liquid CO2 has fluid properties similar to that of supercritical CO2 and is more readily miscible with oil. This study evaluates the EOR potential of low-temperature reservoirs based on the performance of a miscible liquid CO2 flood pilot at the Mumford Hills oil field in Posey County, Indiana. About 7,000 tons (6,350 tonnes) of CO2 were injected into a Mississippian sandstone reservoir over a period of 1 year to demonstrate miscible CO2 EOR in low-temperature oil reservoirs. The reservoir model was calibrated with available historical primary waterflood, and CO2 flood pilot data. The calibrated reservoir model was used to simulate different full-field CO2 EOR development scenarios. The projected oil recovery factors range between 10% and 14%, which compares well to the Permian Basin supercritical CO2 flood recovery range of 8% to 16%. The oil recovery factors from the simulated scenarios suggest that liquid CO2 floods in low-temperature oil reservoirs can achieve an incremental oil recovery similar to deeper, supercritical CO2 floods. Re-evaluating previously overlooked shallow depleted reservoirs as potential candidates for liquid CO2 EOR provides the opportunity to increase the development of these shallow oil reservoirs available for miscible CO2 flooding
- North America > United States > Texas (1.00)
- North America > United States > Illinois (1.00)
- North America > United States > Pennsylvania > Indiana County (0.25)
- North America > United States > Indiana > Posey County (0.25)
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > North America Government > United States Government (0.46)
- North America > United States > Texas > Permian Basin > Yeso Formation (0.99)
- North America > United States > Texas > Permian Basin > Yates Formation (0.99)
- North America > United States > Texas > Permian Basin > Wolfcamp Formation (0.99)
- (44 more...)
Abstract In most reservoirs around the world, paleo oil exists below the free water level and is considered residual oil to natural/geological waterflood. This non-trivial resource of residual oil will not flow by primary or secondary recovery means but requires carefully designed enhance oil recovery (EOR) methods to mobilize it. To date, there is no detailed analysis of paleo oil in the literature simply because it is difficult to obtain a reservoir sample. This study provides a comprehensive paleo oil analysis for samples obtained from reservoir sponge cores. The oil in the sponge core was extracted, analyzed, and compared to main pay zone oil (MPZ). Critical data have been unveiled on paleo oil characterization through fundamental studies on oil quality, fingerprint, filling history, available hydrocarbon components and compounds, and molecular level characterization. It was found that the global composition and overall quality of paleo oil is very similar to the MPZ oil. However, the differences between the two oils were only apparent when the study was further extended to include molecular level analysis and available hydrocarbon components and compounds. These differences may define the appropriate the EOR methods to mobilize this oil and explain trapping mechanisms caused by fluid properties. Gas chromatography studies revealed that paleo oil extracts have the same Pristane/Phytane ratio as the MPZ oil suggesting that they are of the same origins and share the same source rock. Further analysis showed a good match of the Terpane biomarkers between paleo oil extracts and MPZ oil but with slightly less maturity levels. Paleo oil quality was compared to MPZ oil using Pyrolytic Oil Productivity Index (POPI) analysis which indicated same API range as the MPZ oil and same light volatile, thermally distilled and cracked components. Paleo and MPZ oils were also analyzed using nuclear magnetic resonance (NMR) to qualitatively test the similarity of the oil components and measure their apparent viscosities. Both oils have shown very comparable viscosity measurements and NMR signatures. The simulated distillation analysis showed that lighter components in paleo oil are less abundant than MPZ oil while medium to heavy components are relatively similar. Fourier Transform Ion Cyclotron Resonance (FT-ICR) study, which zoomed into the heavier components, revealed that paleo oil has less aromaticity than MPZ oil and lacks aromatic sulfur and di-sulfur compounds, negligible amount of nitrogen compounds, and no resin type components. This study provides in depth information about oil extracted from the residual oil zone, which doesn't flow by primary or secondary recovery means. Up to our knowledge, there is no available information in the literature that explains the components, compounds, quality and behavior of this oil because it is hard to obtain reservoir samples. This data shed light on possible trapping mechanism caused by fluids in place. The study also employed several methods and tools to confirm the conclusions and ensure repeatability of results.
- Geology > Geological Subdiscipline > Geochemistry (0.69)
- Geology > Rock Type > Sedimentary Rock (0.49)
- Energy > Oil & Gas > Upstream (1.00)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (0.70)
- North America > United States > Texas > Permian Basin > Yeso Formation (0.99)
- North America > United States > Texas > Permian Basin > Yates Formation (0.99)
- North America > United States > Texas > Permian Basin > Wolfcamp Formation (0.99)
- (26 more...)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Reduction of residual oil saturation (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Chemical flooding methods (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Core analysis (0.71)