Multiple-Phase Generation During Carbon Dioxide Flooding

1983 ◽  
Vol 23 (04) ◽  
pp. 595-601 ◽  
Author(s):  
Richard L. Henry ◽  
Robert S. Metcalfe
Keyword(s):  
Transition Zone ◽  
Temperature Region ◽  
Phase Region ◽  
Co2 Injection ◽  
Fluid Composition ◽  
Co2 Flooding ◽  
Sweep Efficiency ◽  
Multiple Phase ◽  
Rich Liquid ◽  
Single Contact

Abstract This paper describes to determine the pressure and temperature region in which multiple phases are generated for selected reservoir oils displaced by CO2. The major purposes of this study wereto determine whether single-contact PVT conditions and multiple-contact flow generated multiple phases over equivalent pressures and temperatures, andto determine whether multiple-phase generation would affect mobility. Multiple phases were generated for two reservoir oils of similar composition above the CO2 minimum miscibility pressures (MMP's) for temperatures between 307.5 and 332 K. For a limited temperature range, the pressures over which these multiple phases were observed agreed fairly well with those determined in single-contact PVT cell studies. However, multiple phases were also seen at higher temperatures in the multiple-contact displacements. Pressure-drop data as a function of CO2 injection volume were obtained for displacements within the multiple-phase region and for displacements conducted at pressures above the multiple-phase region. Comparison of these data indicates that multiple-phase generation reduces mobility within the flow system used. Mobility reduction would be beneficial during application of CO2 flooding on a reservoir scale. Introduction Multiple phases (e.g. hydrocarbon-rich liquid, CO2-rich liquid, vapor, and asphaltenes) have been observed for mixtures of some reservoir oils with CO2 in single-contact PVT studies. Reduced injectivity (which was attributed at least partially to formation of multiple phases within the transition zone) was observed in Shell Oil Co.'s North Cross Devonian continuous CO2 flood. These multiple phases could have a relative permeability effect on the mobility of the CO2/oil transition zone and could improve the sweep efficiency of the CO2 flood. Knowledge of the pressure and temperature region in which multiple phases occur is beneficial if a reasonable forecast of performance is to be made. CO2 generally develops miscibility with reservoir oils through mass transfer of components. Because of the changing composition within the CO2/oil transition zone, the phase behavior in a multiple-contact flowing system may be quite different from a static single-contact PVT system in which the overall fluid composition does not change. Consequently, displacement tests are an important contribution to the understanding of multiple-phase flow phenomena. The purpose of this research was to determine the pressure and temperature region in which multiple phases occur for displacements of reservoir oils with CO2 in comparison with the region determined by single-contact PVT data and to determine whether generation of these multiple phases would affect mobility. Test Apparatus CO2 displacements of three reservoir oils were carried out in the coil-microcore apparatus shown in Fig. 1. A positive displacement pump was used to displace fluids (i.e., CO2, oil, and cleanup solvent) through the system and to maintain a constant injection rate during CO2 displacements. A 24.4-m sand packed coil was used to generate the CO2/oil transition zone. SPEJ P. 595^

Phase-Behavior Modeling and Flow Simulation for Low-Temperature CO2 Injection

2015 ◽  
Vol 18 (02) ◽  
pp. 250-263 ◽  
Author(s):  
Huanquan Pan ◽  
Yuguang Chen ◽  
Jonathan Sheffield ◽  
Yih-Bor Chang ◽  
Dengen Zhou
Keyword(s):  
Low Temperatures ◽  
Flow Simulation ◽  
Phase Region ◽  
Simulation Software ◽  
Model Complexity ◽  
Binary Interaction ◽  
Co2 Injection ◽  
West Texas ◽  
Reservoir Fluid ◽  
Rich Liquid

Summary CO2 injection into an oil reservoir at low temperatures (less than 120 °F) can form three hydrocarbon phases—a vapor phase, an oil-rich liquid, and a CO2-rich liquid phase. Most available reservoir simulators cannot handle three-hydrocarbon-phase flash, and the use of two-phase flash may cause significant numerical instability. The issue has been recognized in the industry for a long time. Studies to include three-hydrocarbon-phase flash in compositional simulations exist in the literature. However, this approach results in substantial increases of model complexity and computational cost; thus, it may not be realistic for practical applications (at least for now). In this work, we propose a new pressure/volume/temperature (PVT) modeling procedure to eliminate the three-hydrocarbon-phase region for reservoir-fluid/CO2 mixtures at low temperatures and to study its implication for flow simulation. In our method, the acentric factors of pseudocomponents are adjusted to eliminate the three-hydrocarbon-phase region, which was not considered in any of the previous studies. Then, the experimental data for reservoir-fluid PVT, CO2 swelling test, and minimum miscibility pressure are also matched by adjusting further binary-interaction coefficients, volume-shift parameters, and critical volumes of the pseudocomponents. The procedure is applicable for cases with relatively small three-phase regions (e.g., some fields in west Texas), and can be applied with any PVT simulation software and conventional two-hydrocarbon-phase simulators. The method is considered for two sector models from oil fields in west Texas, with fine-scale (more than 600,000 gridblocks) and upscaled models. Compared with the standard characterization, in which the three-hydrocarbon phases exist, the new fluid model significantly improves the stability of flow simulation, demonstrating the robustness and efficiency of the new procedure. One can view the method as a practical approximation to field-scale simulations of CO2 injection at low temperatures.

Ensemble-Based Optimization of the Water-Alternating-Gas-Injection Process

SPE Journal ◽  
2016 ◽  
Vol 21 (03) ◽  
pp. 0786-0798 ◽  
Author(s):  
Bailian Chen ◽  
Albert C. Reynolds
Keyword(s):  
Net Present Value ◽  
Optimization Technique ◽  
Water Injection ◽  
Mobility Control ◽  
Co2 Injection ◽  
Optimal Controls ◽  
Co2 Flooding ◽  
Displacement Efficiency ◽  
Sweep Efficiency ◽  
Water Alternating Gas

Summary CO2-water-alternating-gas (CO2-WAG) flooding generally leads to higher recovery than either continuous CO2 flooding or waterflooding. Although CO2 injection increases microscopic displacement efficiency, unless complete miscibility is achieved, suboptimal sweep efficiency may be obtained because of gravity segregation and the channeling of CO2 through high-permeability zones or by viscous fingering. Alternating water injection with CO2 injection results in better mobility control and increases sweep efficiency. Water injection also increases pressure that promotes miscibility. However, poorly designed WAG parameters can result in suboptimal WAG performance. In this work, given the number of WAG cycles and the duration of each WAG cycle, we apply a modification of a standard ensemble-based optimization technique to estimate the optimal well controls that maximize life-cycle net present value (NPV). By optimizing the well controls, we implicitly optimize the WAG ratio (volume of water injected divided by the volume of gas injected). We apply the optimization methodology to a synthetic, channelized reservoir. The performances of optimized WAG flooding, optimized waterflooding, and optimized continuous CO2 flooding are compared. Because of the similarity between WAG and surfactant alternating gas (SAG foam), we also optimize the SAG process and provide a more computationally efficient way to optimize the SAG process with the optimal well controls obtained from WAG as the initial guesses for the optimal controls for SAG.

Using Polymer Alternating Gas to Maximize CO2 Flooding Performance

2014 ◽  
Author(s):  
W.. Li ◽  
D. S. Schechter
Keyword(s):  
Oil Recovery ◽  
Polymer Flooding ◽  
Combination Method ◽  
New Combination ◽  
Co2 Injection ◽  
Co2 Flooding ◽  
Sweep Efficiency ◽  
The North ◽  
Carbon Dioxide Co2 ◽  
Wag Injection

Abstract Carbon dioxide (CO2) has been used commercially to recover oil from reservoirs by enhanced oil recovery (EOR) technologies for over 40 years. Currently, CO2 flooding is the second most applied EOR processes in the world behind steamflooding. Water alternating gas (WAG) injection has been a popular method to control mobility and improve volumetric sweep efficiency for CO2 flooding. The average improved recovery is about 9.7%, with a range of 6 to 20% for miscible WAG injection. Despite all the success of WAG injection, sweep efficiency during CO2 flooding is typically a challenge to reach higher oil recovery and better apply the technology. This paper proposes a new combination method called polymer alternating gas (PAG) to improve the volumetric sweep efficiency of the WAG process. The feature of this new method is that polymers are added to water during the WAG process to improve mobility ratio. In the PAG process, polymer flooding and immiscible/miscible CO2 injection are combined. To analyze the feasibility of PAG, models considering both miscible and polymer flooding processes are built to study the performance of PAG. In this paper, the sensitivity of polymer adsorption and concentration are studied. The feasibility of PAG in reservoirs with different permeabilities, different Dykstra-Parsons permeability variation coefficients (VDPs), and different fluids are also studied. A reservoir model from a typical section of the North Burbank Unit (NBU) is used to compare the performance between PAG, WAG, and polymer flooding. This study demonstrates that PAG can significantly improve recovery for immiscible/miscible flooding in homogeneous or heterogeneous reservoirs.

Advances in Midland Basin Expand Boundaries of CO2 EOR in Marginal Pay Areas

2021 ◽  
Vol 73 (06) ◽  
pp. 65-66
Author(s):  
Judy Feder
Keyword(s):  
Oil Recovery ◽  
Large Scale ◽  
Co2 Injection ◽  
Co2 Flooding ◽  
Improved Oil Recovery ◽  
Midland Basin ◽  
The North ◽  
Production Wells ◽  
Original Oil In Place ◽  
Carbon Dioxide Co2

This article, written by JPT Technology Editor Judy Feder, contains highlights of paper SPE 200460, “A Case Study of SACROC CO2 Flooding in Marginal Pay Regions: Improving Asset Performance,” by John Kalteyer, SPE, Kinder Morgan, prepared for the 2020 SPE Improved Oil Recovery Conference, originally scheduled to be held in Tulsa, 18–22 April. The paper has not been peer reviewed. As one of the first fields in the world to use carbon dioxide (CO2) in enhanced oil recovery (EOR), the Scurry Area Canyon Reef Operators Committee (SACROC) unit of the Kelly-Snyder field in the Midland Basin of Texas provides a unique opportunity to study, learn from, and improve upon the development of CO2 flood technology. The complete paper reviews the history of EOR at SACROC, discusses changes in theory over time, and provides a look at the field’s future. Field Overview and Development History The first six pages of the paper discuss the field’s location, geology, and development before June 2000, when Kinder Morgan acquired the SACROC unit and took over as operator. Between initial gas injection in 1972 and 2000, approximately 1 TCF of CO2 had been injected into the Canyon Reef reservoir. Since 2000, cumulative CO2 injection has sur-passed 7 TCF and yielded cumulative EOR of over 180 million bbl. The reservoir is a primarily limestone reef complex containing an estimated original oil in place (OOIP) of just under 3 billion bbl. The reservoir ranges from 200 ft gross thickness in the south to 900 ft in the north, where the limestone matrix averages 8% porosity and 20-md permeability. The Canyon Reef structure is divided into four major intervals, of which the Upper Canyon zone provides the highest-quality pay. The field was discovered in 1948 at a pressure of 3,122 psi. By late 1950, 1,600 production wells had been drilled and the reservoir pressure plummeted, settling as low as 1,700 psi. Waterflooding begun in 1954 enabled the field to continue producing for nearly 20 years, at which time the operators deter-mined that another recovery mechanism would be needed to maximize recovery and reach additional areas of the field. The complete paper discusses various CO2 injection programs that were developed and applied—including a true tertiary response from a miscible CO2 flood in 1981—along with their outcomes. Acquisition and CO2-Injection Redevelopment In June 2000 Kinder Morgan acquired the SACROC Unit and took over as operator. Approximately 6.7 billion bbl of water and 1.3 TCF of CO2 had been injected across the unit to that date, but the daily oil rate of 8,700 B/D was approaching the field’s economic limit. An estimated 40% of the OOIP had been produced through the combination of recovery methods that each previous operator had used. Expanding on the conclusions of its immediate predecessor, the operator initiated large-scale CO2-flood redevelopment in a selection of project areas. These redevelopments were based on several key distinctions differentiating them from previous injection operations.

Modelling and Upscaling Unstable Miscible Displacement Processes: Characterisation of Physical Instabilities

2021 ◽  
Author(s):  
Precious Ogbeiwi ◽  
Karl Stephen
Keyword(s):  
Relative Permeability ◽  
Transport Coefficients ◽  
Miscible Displacement ◽  
Co2 Injection ◽  
Co2 Flooding ◽  
Fine Grid ◽  
Flow Models ◽  
Reservoir Models ◽  
Flood Simulations ◽  
Physical Instabilities

Abstract The compositional simulations are required to model CO2 flooding are computationally expensive particularly for fine-gridded models that have high resolutions, and many components. Upscaling procedures can be used in the subsurface flow models to reduce the high computation requirements of the fine grid simulations and accurately model miscible CO2 flooding. However, the effects of physical instabilities are often not well represented and captured by the upscaling procedures. This paper presents an approach for upscaling of miscible displacements is presented which adequately represents physical instabilities such as viscous and heterogeneity induced fingering on coarser grids using pseudoisation techniques. The approach was applied to compositional numerical simulations of two-dimensional reservoir models with a focus on CO2 injection. Our approach is based on the pseudoisation of relative permeability and the application of transport coefficients to upscale viscous fingering and heterogeneity-induced channelling in a multi-contact miscible CO2 injection. Pseudo-relative permeability curves were computed using a pseudoisation technique and applied in combination with transport coefficients to upscale the behaviour of fine-scale miscible CO2 flood simulations to coarser scales. The accuracy of the results of the pseudoisation procedures were assessed by applying statistical analysis to compare them to the results of the fine grid simulations. It is observed from the results that the coarse models provide accurate predictions of the miscible displacement process and that the fingering regimes are adequately captured in the coarse models. The study presents a framework that can be employed to represent the dynamics of physical instabilities associated with miscible CO2 displacements in upscaled coarser grid reservoir models.

scholarly journals Investigation of Properties Alternation during Super-Critical CO2 Injection in Shale

2019 ◽  
Vol 9 (8) ◽  
pp. 1686 ◽  
Author(s):  
Sai Wang ◽  
Kouqi Liu ◽  
Juan Han ◽  
Kegang Ling ◽  
Hongsheng Wang ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Supercritical Co2 ◽  
Indentation Test ◽  
Nitrogen Adsorption ◽  
Xrd Analysis ◽  
Bet Surface Area ◽  
Co2 Injection ◽  
Co2 Flooding ◽  
Recovery Method ◽  
Injection Process

The low recovery of oil from tight liquid-rich formations is still a major challenge for a tight reservoir. Thus, supercritical CO2 flooding was proposed as an immense potential recovery method for production improvement. While up to date, there have been few studies to account for the formation properties’ variation during the CO2 Enhanced Oil Recovery (EOR) process, especially investigation at the micro-scale. This work conducted a series of measurements to evaluate the rock mechanical change, mineral alteration and the pore structure properties’ variation through the supercritical CO2 (Sc-CO2) injection process. Corresponding to the time variation (0 days, 10 days, 20 days, 30 days and 40 days), the rock mechanical properties were analyzed properly through the nano-indentation test, and the mineralogical alterations were quantified through X-ray diffraction (XRD). In addition, pore structures of the samples were measured through the low-temperature N2 adsorption tests. The results showed that, after Sc-CO2 injection, Young’s modulus of the samples decreases. The nitrogen adsorption results demonstrated that, after the CO2 injection, the mesopore volume of the sample would change as well as the specific Brunauer–Emmett–Teller (BET) surface area which could be aroused from the chemical reactions between the CO2 and some authigenic minerals. XRD analysis results also indicated that mesopore were altered due to the chemical reaction between the injected Sc-CO2 and the minerals.

scholarly journals Experimental Investigation on the Effects of CO2 Displacement Methods on Petrophysical Property Changes of Ultra-Low Permeability Sandstone Reservoirs Near Injection Wells

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 327 ◽  
Author(s):  
Qian Wang ◽  
Shenglai Yang ◽  
Haishui Han ◽  
Lu Wang ◽  
Kun Qian ◽  
...  
Keyword(s):  
Physical Properties ◽  
Pore Size ◽  
Mineral Dissolution ◽  
Co2 Injection ◽  
Low Permeability ◽  
Co2 Flooding ◽  
Formation Water ◽  
Injection Wells ◽  
Rock Interaction ◽  
Sandstone Reservoirs

The petrophysical properties of ultra-low permeability sandstone reservoirs near the injection wells change significantly after CO2 injection for enhanced oil recovery (EOR) and CO2 storage, and different CO2 displacement methods have different effects on these changes. In order to provide the basis for selecting a reasonable displacement method to reduce the damage to these high water cut reservoirs near the injection wells during CO2 injection, CO2-formation water alternate (CO2-WAG) flooding and CO2 flooding experiments were carried out on the fully saturated formation water cores of reservoirs with similar physical properties at in-situ reservoir conditions (78 °, 18 MPa), the similarities and differences of the changes in physical properties of the cores before and after flooding were compared and analyzed. The measurement results of the permeability, porosity, nuclear magnetic resonance (NMR) transversal relaxation time (T2) spectrum and scanning electron microscopy (SEM) of the cores show that the decrease of core permeability after CO2 flooding is smaller than that after CO2-WAG flooding, with almost unchanged porosity in both cores. The proportion of large pores decreases while the proportion of medium pores increases, the proportion of small pores remains almost unchanged, the distribution of pore size of the cores concentrates in the middle. The changes in range and amplitude of the pore size distribution in the core after CO2 flooding are less than those after CO2-WAG flooding. After flooding experiments, clay mineral, clastic fines and salt crystals adhere to some large pores or accumulate at throats, blocking the pores. The changes in core physical properties are the results of mineral dissolution and fines migration, and the differences in these changes under the two displacement methods are caused by the differences in three aspects: the degree of CO2-brine-rock interaction, the radius range of pores where fine migration occurs, the power of fine migration.

Wettability measurements on two sandstones: an experimental investigation before and after CO2 flooding

2020 ◽  
Vol 60 (1) ◽  
pp. 117
Author(s):  
Cut Aja Fauziah ◽  
Emad A. Al-Khdheeawi ◽  
Ahmed Barifcani ◽  
Stefan Iglauer
Keyword(s):  
Contact Angle ◽  
Co2 Storage ◽  
Contact Angle Measurement ◽  
Contact Angles ◽  
Angle Measurement ◽  
Co2 Injection ◽  
Co2 Flooding ◽  
Berea Sandstone ◽  
Before And After ◽  
Carbon Dioxide Co2

Wettability of rock–fluid systems is an important for controlling the carbon dioxide (CO2) movement and the capacities of CO2 geological trapping mechanisms. Although contact angle measurement is considered a potentially scalable parameter for evaluation of the wettability characteristics, there are still large uncertainties associated with the contact angle measurement for CO2–brine–rock systems. Thus, this study experimentally examined the wettability, before and after flooding, of two different samples of sandstone: Berea and Bandera grey sandstones. For both samples, several sets of flooding of brine (5 wt % NaCl + 1 wt % KCl in deionised water), CO2-saturated (live) brine and supercritical CO2 were performed. The contact angle measurements were conducted for the CO2–sandstone system at two different reservoir pressures (10 and 15 MPa) and at a reservoir temperature of 323 K. The results showed that both the advancing and receding contact angles of the sandstone samples after flooding were higher than that measured before flooding (i.e. after CO2 injection the sandstones became more CO2-wet). Moreover, the Bandera grey samples had higher contact angles than Berea sandstone. Thus, we conclude that CO2 flooding altered the sandstone wettability to be more CO2-wet, and Berea sandstone had a higher CO2 storage capacity than Bandera grey sandstone.

Improving CO2 storage and oil recovery by injecting alcohol-treated CO2

2020 ◽  
Vol 60 (2) ◽  
pp. 662
Author(s):  
Saira ◽  
Furqan Le-Hussain
Keyword(s):  
Oil Recovery ◽  
Co2 Sequestration ◽  
Computer Modelling ◽  
Co2 Storage ◽  
Co2 Injection ◽  
Displacement Efficiency ◽  
Sweep Efficiency ◽  
Numerical Studies ◽  
Reservoir Simulator ◽  
Enhance Oil Recovery

Oil recovery and CO2 storage related to CO2 enhance oil recovery are dependent on CO2 miscibility. In case of a depleted oil reservoir, reservoir pressure is not sufficient to achieve miscible or near-miscible condition. This extended abstract presents numerical studies to delineate the effect of alcohol-treated CO2 injection on enhancing miscibility, CO2 storage and oil recovery at immiscible and near-miscible conditions. A compositional reservoir simulator from Computer Modelling Group Ltd. was used to examine the effect of alcohol-treated CO2 on the recovery mechanism. A SPE-5 3D model was used to simulate oil recovery and CO2 storage at field scale for two sets of fluid pairs: (1) pure CO2 and decane and (2) alcohol-treated CO2 and decane. Alcohol-treated CO2 consisted of a mixture of 4 wt% of ethanol and 96 wt% of CO2. All simulations were run at constant temperature (70°C), whereas pressures were determined using a pressure-volume-temperature simulator for immiscible (1400 psi) and near-miscible (1780 psi) conditions. Simulation results reveal that alcohol-treated CO2 injection is found superior to pure CO2 injection in oil recovery (5–9%) and CO2 storage efficiency (4–6%). It shows that alcohol-treated CO2 improves CO2 sweep efficiency. However, improvement in sweep efficiency with alcohol-treated CO2 is more pronounced at higher pressures, whereas improvement in displacement efficiency is more pronounced at lower pressures. The proposed methodology has potential to enhance the feasibility of CO2 sequestration in depleted oil reservoirs and improve both displacement and sweep efficiency of CO2.

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