CO2-EOR Potential Research Articles

Maximizing CO2-EOR Potential for Carbonate Reservoir, Horus Field, Western Desert, Egypt

Maximizing CO2-EOR Potential for Carbonate Reservoir, Horus Field, Western Desert, Egypt

A novel CO2-EOR potential evaluation method based on BO-LightGBM algorithms using hybrid feature mining

The main application of carbon capture, utilization, and storage (CCUS) in oil-and-gas field development engineering is carbon-dioxide enhanced oil recovery (CO2-EOR). However, accurate and rapid assessment of its application potential remains a major challenge. Traditional methods almost always evaluate whether a reservoir is suitable for the CO2-EOR technology by customizing static screening indicators and establishing threshold ranges. That is irrefutably time consuming, laborious, and subjective. In this study, a novel CO2-EOR potential assessment method based on hybrid feature mining and a light gradient boosting machine using Bayesian optimization (BO-LightGBM) is proposed. The fair cut tree and synthetic minority oversampling technique (FCT-SMOTE) were used to correct the missing and unbalanced oilfield data. This has ensured that the model has a balanced high classification accuracy for each type of reservoir. Hybrid feature selection was used to analyze oilfield data to improve the learning ability of the model and improve the calculation efficiency. To achieve multitasking scalability and rapidity, BO-LightGBM was adopted as a classifier for judging the CO2-EOR potential of reservoirs, and a regressor for predicting EOR factor. The proposed classification model has a prediction accuracy of 98.7%, and the proposed regression model has a root mean square error (RMSE) of 1.72, coefficient of determination (R2) of 0.95, and mean absolute percentage error (MAPE) of 18%. Overall, the CO2-EOR potential assessment method proposed in this study has the advantages of high accuracy, scalability, and speed. In addition, it should be emphasized that using static weight indicators to evaluate CO2-EOR potential may not be appropriate. Rather, machine learning (ML) methods to evaluate the application potential of CO2-EOR is recommended. This is because ML methods can divide the scope of multiple factors simultaneously, providing more intelligent and accurate results.

CO2-Enhanced Oil Recovery Mechanism in Canadian Bakken Shale

The recovery factor in unconventional reservoirs is typically 5–10%, with extensive hydraulic fracturing and infill drilling to maintain the production rate. Concurrently, the rush towards decarbonization is opening up new possibilities for CO2 utilization, enhanced oil recovery (EOR) being one example. CO2-EOR in unconventional reservoirs presents an opportunity for both financial gain through improved recovery factors, as well as reducing the carbon footprint of the produced oil. In this work, we examine the CO2-EOR potential in 4 organic-rich shale samples from the Canadian Bakken Formation. A number of characterization tests alongside CO2 extraction experiments were performed to gain insight into the controlling factors of CO2-EOR in these ultra-tight formations. The results show CO2 can penetrate the tight rock matrix and recover a substantial amount of hydrocarbon. Concentration gradient driven diffusion is the dominant form of recovery.

Carbon capture and storage opportunities in the west coast of India

In this paper, opportunities for carbon capture and storage (CCS) in India’s west coast is investigated. Specifically, CO2 emissions from the power and industry sectors in the states of Maharashtra and Gujarat and subsurface sinks to store them in oil fields, gas fields or saline aquifers in the closest sedimentary basins are quantified on a plant-by-plant and field-by-field basis.Results indicate that CO2 emission from these two states is 221 Mtpa and 115 Mtpa from the power and industry sectors, respectively. The mid CO2 storage capacity in nearby sedimentary basins is 141 Gt, enough to store 420 years of CO2 emission. Of this, 137 Gt (97.4%) come from saline aquifers, 2.23 Gt (1.6%) from gas fields, and only 1.4 Gt (1.0%) from oil fields. Furthermore, CO2 injection has the potential of recovering 2,620 MMbbl from oil fields and 118 MMbbl from gas fields through enhanced oil recovery (EOR) and enhanced gas recovery (EGR), respectively. The most significant CO2-EOR potential (1,453 MMbbl) is in the offshore Mumbai High oil field. Currently, most gas fields are under primary production and, therefore, will only be ready for CO2 storage when they are near depletion.Results of a CO2 source–sink mapping exercise suggest using four CCS hubs to connect regional CO2 sources and sinks. They are Mumbai, Nagpur and Chandrapur in the state of Maharashtra and Hazira in the state of Gujarat. These hubs can be used to temporarily store CO2 before it is transported to nearby oil fields or saline aquifers for permanent storage. Implementation of CCS projects based on these hubs can remove up to 168 Mtpa CO2 or 50% of stationary emission of these two states with a CO2 source–sink distance of 150 km or less, thus making a significant contribution to India’s decarbonization.

NMR characterization of a tight sand's pore structures and fluid mobility: An experimental investigation for CO2 EOR potential

Successful designs of the enhanced oil recovery operation and production forecasts require careful characterization of the reservoir rocks’ pore structures and fluids within. In contrary to the commonly adopted assumptions, strengths of the bonding forces resisting fluid displacement in tight sands do not necessarily correlate with the pore sizes. Free fluid (FF) exists across pores of a broad spectrum of sizes and vice versa; fluids bonded firmly to the pore surface by capillary force (i.e., capillary bound fluid, CAF) and electrochemical forces (i.e., clay bound fluid, CBF) may exist in larger pores too; this brings the need of laboratory experiments, particularly at an environment similar to that in-situ. Here, we investigate the pore size distribution and fluid movement in tight sand samples. Fluids in the fully saturated samples are removed sequentially via centrifugation and thermal treatment. NMR responses measured during this process allows the establishment of the characteristic T2 curves of TFF, TCAF, and TCBF. We compare these curves with the T2 curves measured during cycles of a laboratory-scale CO2 HnP (huff-n-puff) experiments to assess the recovery rate against fluid types and pore sizes. Low field NMR experiments allow us to investigate the fluid displacements across pores of different sizes, represented by the T2 relaxation times, at pressurized environments. Through these experiments, we found most FF, including those stored in medium/small-sized pores, are recovered within the first two cycles along with significant CAF from small to medium pores; no displacement of CBF is observed.

Investigating CO2-enhanced oil recovery potential for a mature oil field: a case study based on Ankleshwar oil field, Cambay Basin, India

CO2-enhanced oil recovery (EOR) is an upcoming technology in India. At present, no Indian field is under CO2-EOR and implementation of this technique to a mature oil field needs a rigorous study. In the present work, we made an attempt to investigate the CO2-EOR potential of a mature oil field, situated in Cambay Basin, India. The field was put on production in 1961, and it has produced approximately 65.36 MMt oil during massive water flooding, leading to residual oil reserves of 6.49 MMt. The operator of the field is interested in incremental oil recovery from this field by injecting CO2. This requires estimation of incremental oil recovery potential of the field by carrying out systematic study. We, therefore, developed a conceptual model inspired by Ankleshwar oil field of Cambay Basin using available information provided by the field operator and carried out systematic studies to establish an optimized strategy for CO2 injection. To achieve this goal, we investigated the effect of various operational parameters on oil recovery efficiency of our conceptual model and selected optimum parameters for reservoir simulations. Simulation results clearly indicate that the field can be a good candidate for CO2-EOR, and an additional oil recovery of 10.4% of hydrocarbon pore volume is feasible. Major outcome of the study is an optimized black-oil simulation model, which is in good agreement with the fine grid compositional model of high accuracy. The proposed black-oil model can easily be implemented and updated compared with compute intensive finer compositional simulation model.

EOR Potential from CO2 Captured from Coal-Fired Power Plants in the Upper Cretaceous (Cenomanian) Woodbine Group, East Texas Basin, and Southeastern Texas Gulf Coast, USA

The East Texas Basin and southeastern Texas Gulf Coast contain a variety of co-located CO2 sources and sinks that may facilitate development of new clean-coal facilities. These facilities can be linked to mature oil fields with potential for enhanced oil recovery (EOR) from miscible CO2 floods. Twenty-three reservoirs in the East Texas Basin and southeastern Texas Gulf Coast, assuming a 15% recovery factor of original oil in place (OOIP), have a CO2-EOR potential for recovery of ~9,697,000 m3 [~62.2 million stock tank barrels] of oil. A network of new CO2 pipelines can link these fields to existing power plants near lignite mine mouths in east and southeast Texas. Representative oil fields in the Woodbine Group illustrate fluvial and deltaic facies variability and different sandstone-body architectures with varying controls on potential CO2 capacity. Reservoir heterogeneity, fluid flow, hydrocarbon production, and potential CO2 capacity in the Woodbine Group in the structurally simple East Texas field are mainly a function of facies architecture. The Woodbine Group in East Texas field contains a lower section of narrow and lenticular sandstone bodies in a fluvially dominated deltaic system. Pressure and production data indicate that additional oil recovery in the lower Woodbine deltaic section in East Texas field is low in muddy, low-permeability prodelta, and distal-delta-front facies. In contrast, oil recovery is greater in sandy distributary-channel sandstones. Core-plug data show that distributary-channel and channel-mouth-bar sandstones in the field have high median-permeability values, and therefore a greater potential for CO2 capacity. These deltaic deposits are overlain disconformably by an upper section of continuous, coarse-grained fluvial deposits that favor high CO2 capacity owing to Darcy-class permeability and extensive vertical and lateral reservoir continuity. In contrast, Woodbine fields in southeast Texas represent distal-deltaic facies. CO2 capacity and EOR potential in these fields are limited by thin distributary-channel and crevasse-splay deposits that contain abundant mudstone beds that may serve to segregate-injected CO2 into small reservoir compartments.

Estimating CO2-EOR Potential and Co-sequestration Capacity in Ohio's Depleted Oil Fields

Abstract The goal of this project is to develop process understanding and evaluate technical and economic feasibility of CO2 utilization and storage in Ohio. Our focus will be on depleted oil fields in the Clinton sandstone in eastern Ohio at depths ranging from 3400 to 5000 ft and the Knox dolomite in North-Central Ohio at depths ranging from 3000 to 8000 ft. These fields appear to be promising candidates for CO2-assisted EOR because of poor primary recovery efficiency that leaves behind ∼80-90% original oil in place. However, a systematic assessment of enhanced recovery and co-sequestration potential in these under-pressured low- permeability depleted oil fields does not appear to have been undertaken – which is the focus of this research project. This paper describes ongoing activities in the areas of source-sink matching, production history assessment, reservoir characterization and fluid property characterization, as well as plans for reservoir simulation.

Screening of Oil Pools on Alaskan North Slope and Phase Behavior Study of Viscous Oil and CO2 System in Conjunction with CO2 Sequestration

Carbon dioxide gas, a greenhouse gas (GHG), is released in the atmosphere by combustion of solid waste, wood, and fossil fuels for energy generation. Due to conspicuous absence of CO2 sequestration studies for Alaska, the study of CO2 sequestration options on North Slope has a very important role to play. The screening of the oil reservoirs to evaluate the technical feasibility with respect to their CO2-EOR potential was performed by calculating the rank of the oil reservoirs with parametric approach. CMG-WinProp® simulator was used to predict phase behavior for CO2 injection in viscous oil by tuning the equation-of-state.