New Mexico Tech

Senior Research Scientist

Senior Scientist and Head of the Naturally Fractured Reservoir Group. Extensive experience in CO2 injection and naturally fractured reservoirs.

Texas A&M University

Professor

David worked at Texas A&M University as a Professor

Pioneer Natural Resources

Affiliation as Technical Specialist

Affiliated off and on with Pioneer Natural Resources (originally Parker and Parsley) since being primary author and Principal Investigator for a Class III Department of Energy pilot project in the Spraberry Trend Area, initiated in 1993. Co-managed development of CO2 pilot project, that also involved water injection in vertical and horizontal wells. Managed all the laboratory support work. Full-time reservoir engineer for three summers with Pioneer in 2005 and 2006 and 2011. Analyzed all waterfloods in unitized areas, past and present in The Spraberry Trend Area.

PEMEX

Consultant

Evaluated approximately 25 fields in the South Region of Mexico for PEMEX. These are all naturally fractured carbonates, mainly Cretaceous. These fields were evalauted for water injection or EOR with CO2 injection.

Network of Excellence in Training (NExT)

Short Course Instructor

Taught over 100 short courses in:

Reservoir Engineering
Formation Evaluation
Naturally Fractured Reservoirs
Waterflooding
Production Engineering
CO2 Enhanced Oil Recovery

Long Term Stability of Acrylamide Based Polymers during Chemically Assisted CO2 WAG EOR

Society of Petroleum Engineers

CO 2 flooding often results in poor sweep efficiency due to the high mobility ratio caused by its low viscosity. To mitigate this problem, the alternate injection of water and CO 2 slugs, known as the water-alternating-gas process (WAG), is widely applied. Recently, numerical simulation and core flood experiments indicate that the use of chemicals in the water slug may improve mobility control during WAG, thus increasing the ultimate recovery. Therefore, the study of the stability of common polymers used for EOR applications in CO 2 saturated environments becomes necessary to address the technical and economic feasibility of this process. In this paper, we report the results of two commonly applied EOR polymers, a co-polymer of acrylamide and acrylate and a co-polymer of acrylamide and ATBS . To establish a base line for comparison, parallel experiments were conducted in two different oxygen free environments: one with CO 2 and the other with nitrogen. Samples were hydrated and aged at reservoir temperature over 300 days. To isolate the effect of CO 2, polymer thermal and chemical degradation were reduced by stripping out dissolved oxygen and decreasing divalent cation concentration from the water. Polymer samples were removed at different times and their viscosity was measured as a function of shear rate and fitted to a power law model. The ability of the polymer solutions to retain their original viscosity over time was used to quantify polymer degradation. The results of this work show that CO 2 impacts polymer stability, causing further degradation in both polymers tested. The co-polymer of acrylamide and ATBS exhibited higher resistance to CO 2 degradation as it was able to retain 94 % of its original viscosity, compared with the co-polymer of acrylamide and acrylate which only retained 56 %. We conclude that commercial polymers can be used during chemically assisted CO 2 WAG when low divalent cation water is used at a reservoir temperature of 122 F.

Long Term Stability of Acrylamide Based Polymers during Chemically Assisted CO2 WAG EOR

Society of Petroleum Engineers

CO 2 flooding often results in poor sweep efficiency due to the high mobility ratio caused by its low viscosity. To mitigate this problem, the alternate injection of water and CO 2 slugs, known as the water-alternating-gas process (WAG), is widely applied. Recently, numerical simulation and core flood experiments indicate that the use of chemicals in the water slug may improve mobility control during WAG, thus increasing the ultimate recovery. Therefore, the study of the stability of common polymers used for EOR applications in CO 2 saturated environments becomes necessary to address the technical and economic feasibility of this process. In this paper, we report the results of two commonly applied EOR polymers, a co-polymer of acrylamide and acrylate and a co-polymer of acrylamide and ATBS . To establish a base line for comparison, parallel experiments were conducted in two different oxygen free environments: one with CO 2 and the other with nitrogen. Samples were hydrated and aged at reservoir temperature over 300 days. To isolate the effect of CO 2, polymer thermal and chemical degradation were reduced by stripping out dissolved oxygen and decreasing divalent cation concentration from the water. Polymer samples were removed at different times and their viscosity was measured as a function of shear rate and fitted to a power law model. The ability of the polymer solutions to retain their original viscosity over time was used to quantify polymer degradation. The results of this work show that CO 2 impacts polymer stability, causing further degradation in both polymers tested. The co-polymer of acrylamide and ATBS exhibited higher resistance to CO 2 degradation as it was able to retain 94 % of its original viscosity, compared with the co-polymer of acrylamide and acrylate which only retained 56 %. We conclude that commercial polymers can be used during chemically assisted CO 2 WAG when low divalent cation water is used at a reservoir temperature of 122 F.

Long Term Stability of Acrylamide Based Polymers during Chemically Assisted CO2 WAG EOR

Society of Petroleum Engineers

CO 2 flooding often results in poor sweep efficiency due to the high mobility ratio caused by its low viscosity. To mitigate this problem, the alternate injection of water and CO 2 slugs, known as the water-alternating-gas process (WAG), is widely applied. Recently, numerical simulation and core flood experiments indicate that the use of chemicals in the water slug may improve mobility control during WAG, thus increasing the ultimate recovery. Therefore, the study of the stability of common polymers used for EOR applications in CO 2 saturated environments becomes necessary to address the technical and economic feasibility of this process. In this paper, we report the results of two commonly applied EOR polymers, a co-polymer of acrylamide and acrylate and a co-polymer of acrylamide and ATBS . To establish a base line for comparison, parallel experiments were conducted in two different oxygen free environments: one with CO 2 and the other with nitrogen. Samples were hydrated and aged at reservoir temperature over 300 days. To isolate the effect of CO 2, polymer thermal and chemical degradation were reduced by stripping out dissolved oxygen and decreasing divalent cation concentration from the water. Polymer samples were removed at different times and their viscosity was measured as a function of shear rate and fitted to a power law model. The ability of the polymer solutions to retain their original viscosity over time was used to quantify polymer degradation. The results of this work show that CO 2 impacts polymer stability, causing further degradation in both polymers tested. The co-polymer of acrylamide and ATBS exhibited higher resistance to CO 2 degradation as it was able to retain 94 % of its original viscosity, compared with the co-polymer of acrylamide and acrylate which only retained 56 %. We conclude that commercial polymers can be used during chemically assisted CO 2 WAG when low divalent cation water is used at a reservoir temperature of 122 F.

Long Term Stability of Acrylamide Based Polymers during Chemically Assisted CO2 WAG EOR

Society of Petroleum Engineers

CO 2 flooding often results in poor sweep efficiency due to the high mobility ratio caused by its low viscosity. To mitigate this problem, the alternate injection of water and CO 2 slugs, known as the water-alternating-gas process (WAG), is widely applied. Recently, numerical simulation and core flood experiments indicate that the use of chemicals in the water slug may improve mobility control during WAG, thus increasing the ultimate recovery. Therefore, the study of the stability of common polymers used for EOR applications in CO 2 saturated environments becomes necessary to address the technical and economic feasibility of this process. In this paper, we report the results of two commonly applied EOR polymers, a co-polymer of acrylamide and acrylate and a co-polymer of acrylamide and ATBS . To establish a base line for comparison, parallel experiments were conducted in two different oxygen free environments: one with CO 2 and the other with nitrogen. Samples were hydrated and aged at reservoir temperature over 300 days. To isolate the effect of CO 2, polymer thermal and chemical degradation were reduced by stripping out dissolved oxygen and decreasing divalent cation concentration from the water. Polymer samples were removed at different times and their viscosity was measured as a function of shear rate and fitted to a power law model. The ability of the polymer solutions to retain their original viscosity over time was used to quantify polymer degradation. The results of this work show that CO 2 impacts polymer stability, causing further degradation in both polymers tested. The co-polymer of acrylamide and ATBS exhibited higher resistance to CO 2 degradation as it was able to retain 94 % of its original viscosity, compared with the co-polymer of acrylamide and acrylate which only retained 56 %. We conclude that commercial polymers can be used during chemically assisted CO 2 WAG when low divalent cation water is used at a reservoir temperature of 122 F.

Asphaltene Gradients and Tar Mat Formation via Downhole Fluid Analysis and Novel Asphaltene Science

Rio Oil & Gas Expo and Conference

Mullins, O.C., Zuo, J., Freed, D., Elshahawi, H., Dong, C., Pfeiffer, T., and Schechter, D.: “Asphaltene Gradients and Tar Mat Formation via Downhole Fluid Analysis and Novel Asphaltene Science”, Paper IBP 3242-10 Presented at the 2010 Rio Oil & Gas Expo and Conference held at Rio de Janeiro, Brazil, Sept 13-16, 2010.

Long Term Stability of Acrylamide Based Polymers during Chemically Assisted CO2 WAG EOR

Society of Petroleum Engineers

CO 2 flooding often results in poor sweep efficiency due to the high mobility ratio caused by its low viscosity. To mitigate this problem, the alternate injection of water and CO 2 slugs, known as the water-alternating-gas process (WAG), is widely applied. Recently, numerical simulation and core flood experiments indicate that the use of chemicals in the water slug may improve mobility control during WAG, thus increasing the ultimate recovery. Therefore, the study of the stability of common polymers used for EOR applications in CO 2 saturated environments becomes necessary to address the technical and economic feasibility of this process. In this paper, we report the results of two commonly applied EOR polymers, a co-polymer of acrylamide and acrylate and a co-polymer of acrylamide and ATBS . To establish a base line for comparison, parallel experiments were conducted in two different oxygen free environments: one with CO 2 and the other with nitrogen. Samples were hydrated and aged at reservoir temperature over 300 days. To isolate the effect of CO 2, polymer thermal and chemical degradation were reduced by stripping out dissolved oxygen and decreasing divalent cation concentration from the water. Polymer samples were removed at different times and their viscosity was measured as a function of shear rate and fitted to a power law model. The ability of the polymer solutions to retain their original viscosity over time was used to quantify polymer degradation. The results of this work show that CO 2 impacts polymer stability, causing further degradation in both polymers tested. The co-polymer of acrylamide and ATBS exhibited higher resistance to CO 2 degradation as it was able to retain 94 % of its original viscosity, compared with the co-polymer of acrylamide and acrylate which only retained 56 %. We conclude that commercial polymers can be used during chemically assisted CO 2 WAG when low divalent cation water is used at a reservoir temperature of 122 F.

Long Term Stability of Acrylamide Based Polymers during Chemically Assisted CO2 WAG EOR

Society of Petroleum Engineers

CO 2 flooding often results in poor sweep efficiency due to the high mobility ratio caused by its low viscosity. To mitigate this problem, the alternate injection of water and CO 2 slugs, known as the water-alternating-gas process (WAG), is widely applied. Recently, numerical simulation and core flood experiments indicate that the use of chemicals in the water slug may improve mobility control during WAG, thus increasing the ultimate recovery. Therefore, the study of the stability of common polymers used for EOR applications in CO 2 saturated environments becomes necessary to address the technical and economic feasibility of this process. In this paper, we report the results of two commonly applied EOR polymers, a co-polymer of acrylamide and acrylate and a co-polymer of acrylamide and ATBS . To establish a base line for comparison, parallel experiments were conducted in two different oxygen free environments: one with CO 2 and the other with nitrogen. Samples were hydrated and aged at reservoir temperature over 300 days. To isolate the effect of CO 2, polymer thermal and chemical degradation were reduced by stripping out dissolved oxygen and decreasing divalent cation concentration from the water. Polymer samples were removed at different times and their viscosity was measured as a function of shear rate and fitted to a power law model. The ability of the polymer solutions to retain their original viscosity over time was used to quantify polymer degradation. The results of this work show that CO 2 impacts polymer stability, causing further degradation in both polymers tested. The co-polymer of acrylamide and ATBS exhibited higher resistance to CO 2 degradation as it was able to retain 94 % of its original viscosity, compared with the co-polymer of acrylamide and acrylate which only retained 56 %. We conclude that commercial polymers can be used during chemically assisted CO 2 WAG when low divalent cation water is used at a reservoir temperature of 122 F.

Asphaltene Gradients and Tar Mat Formation via Downhole Fluid Analysis and Novel Asphaltene Science

Rio Oil & Gas Expo and Conference

Mullins, O.C., Zuo, J., Freed, D., Elshahawi, H., Dong, C., Pfeiffer, T., and Schechter, D.: “Asphaltene Gradients and Tar Mat Formation via Downhole Fluid Analysis and Novel Asphaltene Science”, Paper IBP 3242-10 Presented at the 2010 Rio Oil & Gas Expo and Conference held at Rio de Janeiro, Brazil, Sept 13-16, 2010.

Impact of Surfactants for Wettability Alteration in Stimulation Fluids and the Potential for Surfactant EOR in Unconventional Liquid Reservoirs

Society of Petroleum Engineers

Long Term Stability of Acrylamide Based Polymers during Chemically Assisted CO2 WAG EOR

Society of Petroleum Engineers

CO 2 flooding often results in poor sweep efficiency due to the high mobility ratio caused by its low viscosity. To mitigate this problem, the alternate injection of water and CO 2 slugs, known as the water-alternating-gas process (WAG), is widely applied. Recently, numerical simulation and core flood experiments indicate that the use of chemicals in the water slug may improve mobility control during WAG, thus increasing the ultimate recovery. Therefore, the study of the stability of common polymers used for EOR applications in CO 2 saturated environments becomes necessary to address the technical and economic feasibility of this process. In this paper, we report the results of two commonly applied EOR polymers, a co-polymer of acrylamide and acrylate and a co-polymer of acrylamide and ATBS . To establish a base line for comparison, parallel experiments were conducted in two different oxygen free environments: one with CO 2 and the other with nitrogen. Samples were hydrated and aged at reservoir temperature over 300 days. To isolate the effect of CO 2, polymer thermal and chemical degradation were reduced by stripping out dissolved oxygen and decreasing divalent cation concentration from the water. Polymer samples were removed at different times and their viscosity was measured as a function of shear rate and fitted to a power law model. The ability of the polymer solutions to retain their original viscosity over time was used to quantify polymer degradation. The results of this work show that CO 2 impacts polymer stability, causing further degradation in both polymers tested. The co-polymer of acrylamide and ATBS exhibited higher resistance to CO 2 degradation as it was able to retain 94 % of its original viscosity, compared with the co-polymer of acrylamide and acrylate which only retained 56 %. We conclude that commercial polymers can be used during chemically assisted CO 2 WAG when low divalent cation water is used at a reservoir temperature of 122 F.

Long Term Stability of Acrylamide Based Polymers during Chemically Assisted CO2 WAG EOR

Society of Petroleum Engineers

CO 2 flooding often results in poor sweep efficiency due to the high mobility ratio caused by its low viscosity. To mitigate this problem, the alternate injection of water and CO 2 slugs, known as the water-alternating-gas process (WAG), is widely applied. Recently, numerical simulation and core flood experiments indicate that the use of chemicals in the water slug may improve mobility control during WAG, thus increasing the ultimate recovery. Therefore, the study of the stability of common polymers used for EOR applications in CO 2 saturated environments becomes necessary to address the technical and economic feasibility of this process. In this paper, we report the results of two commonly applied EOR polymers, a co-polymer of acrylamide and acrylate and a co-polymer of acrylamide and ATBS . To establish a base line for comparison, parallel experiments were conducted in two different oxygen free environments: one with CO 2 and the other with nitrogen. Samples were hydrated and aged at reservoir temperature over 300 days. To isolate the effect of CO 2, polymer thermal and chemical degradation were reduced by stripping out dissolved oxygen and decreasing divalent cation concentration from the water. Polymer samples were removed at different times and their viscosity was measured as a function of shear rate and fitted to a power law model. The ability of the polymer solutions to retain their original viscosity over time was used to quantify polymer degradation. The results of this work show that CO 2 impacts polymer stability, causing further degradation in both polymers tested. The co-polymer of acrylamide and ATBS exhibited higher resistance to CO 2 degradation as it was able to retain 94 % of its original viscosity, compared with the co-polymer of acrylamide and acrylate which only retained 56 %. We conclude that commercial polymers can be used during chemically assisted CO 2 WAG when low divalent cation water is used at a reservoir temperature of 122 F.

Asphaltene Gradients and Tar Mat Formation via Downhole Fluid Analysis and Novel Asphaltene Science

Rio Oil & Gas Expo and Conference

Mullins, O.C., Zuo, J., Freed, D., Elshahawi, H., Dong, C., Pfeiffer, T., and Schechter, D.: “Asphaltene Gradients and Tar Mat Formation via Downhole Fluid Analysis and Novel Asphaltene Science”, Paper IBP 3242-10 Presented at the 2010 Rio Oil & Gas Expo and Conference held at Rio de Janeiro, Brazil, Sept 13-16, 2010.

Impact of Surfactants for Wettability Alteration in Stimulation Fluids and the Potential for Surfactant EOR in Unconventional Liquid Reservoirs

Society of Petroleum Engineers

Utilization of Voronoi Gridding for Simulation of Heterogeneous, Discrete Fracture Networks Using Outcrop and X-Ray CT Scanning with Non Uniform Aperture Distribution of Rough Fracture Surfaces and Intersecting Fractures

Journal of Petroleum Science Research

Long Term Stability of Acrylamide Based Polymers during Chemically Assisted CO2 WAG EOR

Society of Petroleum Engineers

CO 2 flooding often results in poor sweep efficiency due to the high mobility ratio caused by its low viscosity. To mitigate this problem, the alternate injection of water and CO 2 slugs, known as the water-alternating-gas process (WAG), is widely applied. Recently, numerical simulation and core flood experiments indicate that the use of chemicals in the water slug may improve mobility control during WAG, thus increasing the ultimate recovery. Therefore, the study of the stability of common polymers used for EOR applications in CO 2 saturated environments becomes necessary to address the technical and economic feasibility of this process. In this paper, we report the results of two commonly applied EOR polymers, a co-polymer of acrylamide and acrylate and a co-polymer of acrylamide and ATBS . To establish a base line for comparison, parallel experiments were conducted in two different oxygen free environments: one with CO 2 and the other with nitrogen. Samples were hydrated and aged at reservoir temperature over 300 days. To isolate the effect of CO 2, polymer thermal and chemical degradation were reduced by stripping out dissolved oxygen and decreasing divalent cation concentration from the water. Polymer samples were removed at different times and their viscosity was measured as a function of shear rate and fitted to a power law model. The ability of the polymer solutions to retain their original viscosity over time was used to quantify polymer degradation. The results of this work show that CO 2 impacts polymer stability, causing further degradation in both polymers tested. The co-polymer of acrylamide and ATBS exhibited higher resistance to CO 2 degradation as it was able to retain 94 % of its original viscosity, compared with the co-polymer of acrylamide and acrylate which only retained 56 %. We conclude that commercial polymers can be used during chemically assisted CO 2 WAG when low divalent cation water is used at a reservoir temperature of 122 F.

Long Term Stability of Acrylamide Based Polymers during Chemically Assisted CO2 WAG EOR

Society of Petroleum Engineers

CO 2 flooding often results in poor sweep efficiency due to the high mobility ratio caused by its low viscosity. To mitigate this problem, the alternate injection of water and CO 2 slugs, known as the water-alternating-gas process (WAG), is widely applied. Recently, numerical simulation and core flood experiments indicate that the use of chemicals in the water slug may improve mobility control during WAG, thus increasing the ultimate recovery. Therefore, the study of the stability of common polymers used for EOR applications in CO 2 saturated environments becomes necessary to address the technical and economic feasibility of this process. In this paper, we report the results of two commonly applied EOR polymers, a co-polymer of acrylamide and acrylate and a co-polymer of acrylamide and ATBS . To establish a base line for comparison, parallel experiments were conducted in two different oxygen free environments: one with CO 2 and the other with nitrogen. Samples were hydrated and aged at reservoir temperature over 300 days. To isolate the effect of CO 2, polymer thermal and chemical degradation were reduced by stripping out dissolved oxygen and decreasing divalent cation concentration from the water. Polymer samples were removed at different times and their viscosity was measured as a function of shear rate and fitted to a power law model. The ability of the polymer solutions to retain their original viscosity over time was used to quantify polymer degradation. The results of this work show that CO 2 impacts polymer stability, causing further degradation in both polymers tested. The co-polymer of acrylamide and ATBS exhibited higher resistance to CO 2 degradation as it was able to retain 94 % of its original viscosity, compared with the co-polymer of acrylamide and acrylate which only retained 56 %. We conclude that commercial polymers can be used during chemically assisted CO 2 WAG when low divalent cation water is used at a reservoir temperature of 122 F.

Asphaltene Gradients and Tar Mat Formation via Downhole Fluid Analysis and Novel Asphaltene Science

Rio Oil & Gas Expo and Conference

Mullins, O.C., Zuo, J., Freed, D., Elshahawi, H., Dong, C., Pfeiffer, T., and Schechter, D.: “Asphaltene Gradients and Tar Mat Formation via Downhole Fluid Analysis and Novel Asphaltene Science”, Paper IBP 3242-10 Presented at the 2010 Rio Oil & Gas Expo and Conference held at Rio de Janeiro, Brazil, Sept 13-16, 2010.

Impact of Surfactants for Wettability Alteration in Stimulation Fluids and the Potential for Surfactant EOR in Unconventional Liquid Reservoirs

Society of Petroleum Engineers

Utilization of Voronoi Gridding for Simulation of Heterogeneous, Discrete Fracture Networks Using Outcrop and X-Ray CT Scanning with Non Uniform Aperture Distribution of Rough Fracture Surfaces and Intersecting Fractures

Journal of Petroleum Science Research

Polymer-WAG Simulation

2014 SPE EOR Conference at Oil & Gas West Asia

Long Term Stability of Acrylamide Based Polymers during Chemically Assisted CO2 WAG EOR

Society of Petroleum Engineers

CO 2 flooding often results in poor sweep efficiency due to the high mobility ratio caused by its low viscosity. To mitigate this problem, the alternate injection of water and CO 2 slugs, known as the water-alternating-gas process (WAG), is widely applied. Recently, numerical simulation and core flood experiments indicate that the use of chemicals in the water slug may improve mobility control during WAG, thus increasing the ultimate recovery. Therefore, the study of the stability of common polymers used for EOR applications in CO 2 saturated environments becomes necessary to address the technical and economic feasibility of this process. In this paper, we report the results of two commonly applied EOR polymers, a co-polymer of acrylamide and acrylate and a co-polymer of acrylamide and ATBS . To establish a base line for comparison, parallel experiments were conducted in two different oxygen free environments: one with CO 2 and the other with nitrogen. Samples were hydrated and aged at reservoir temperature over 300 days. To isolate the effect of CO 2, polymer thermal and chemical degradation were reduced by stripping out dissolved oxygen and decreasing divalent cation concentration from the water. Polymer samples were removed at different times and their viscosity was measured as a function of shear rate and fitted to a power law model. The ability of the polymer solutions to retain their original viscosity over time was used to quantify polymer degradation. The results of this work show that CO 2 impacts polymer stability, causing further degradation in both polymers tested. The co-polymer of acrylamide and ATBS exhibited higher resistance to CO 2 degradation as it was able to retain 94 % of its original viscosity, compared with the co-polymer of acrylamide and acrylate which only retained 56 %. We conclude that commercial polymers can be used during chemically assisted CO 2 WAG when low divalent cation water is used at a reservoir temperature of 122 F.

Long Term Stability of Acrylamide Based Polymers during Chemically Assisted CO2 WAG EOR

Society of Petroleum Engineers

CO 2 flooding often results in poor sweep efficiency due to the high mobility ratio caused by its low viscosity. To mitigate this problem, the alternate injection of water and CO 2 slugs, known as the water-alternating-gas process (WAG), is widely applied. Recently, numerical simulation and core flood experiments indicate that the use of chemicals in the water slug may improve mobility control during WAG, thus increasing the ultimate recovery. Therefore, the study of the stability of common polymers used for EOR applications in CO 2 saturated environments becomes necessary to address the technical and economic feasibility of this process. In this paper, we report the results of two commonly applied EOR polymers, a co-polymer of acrylamide and acrylate and a co-polymer of acrylamide and ATBS . To establish a base line for comparison, parallel experiments were conducted in two different oxygen free environments: one with CO 2 and the other with nitrogen. Samples were hydrated and aged at reservoir temperature over 300 days. To isolate the effect of CO 2, polymer thermal and chemical degradation were reduced by stripping out dissolved oxygen and decreasing divalent cation concentration from the water. Polymer samples were removed at different times and their viscosity was measured as a function of shear rate and fitted to a power law model. The ability of the polymer solutions to retain their original viscosity over time was used to quantify polymer degradation. The results of this work show that CO 2 impacts polymer stability, causing further degradation in both polymers tested. The co-polymer of acrylamide and ATBS exhibited higher resistance to CO 2 degradation as it was able to retain 94 % of its original viscosity, compared with the co-polymer of acrylamide and acrylate which only retained 56 %. We conclude that commercial polymers can be used during chemically assisted CO 2 WAG when low divalent cation water is used at a reservoir temperature of 122 F.

Asphaltene Gradients and Tar Mat Formation via Downhole Fluid Analysis and Novel Asphaltene Science

Rio Oil & Gas Expo and Conference

Mullins, O.C., Zuo, J., Freed, D., Elshahawi, H., Dong, C., Pfeiffer, T., and Schechter, D.: “Asphaltene Gradients and Tar Mat Formation via Downhole Fluid Analysis and Novel Asphaltene Science”, Paper IBP 3242-10 Presented at the 2010 Rio Oil & Gas Expo and Conference held at Rio de Janeiro, Brazil, Sept 13-16, 2010.

Impact of Surfactants for Wettability Alteration in Stimulation Fluids and the Potential for Surfactant EOR in Unconventional Liquid Reservoirs

Society of Petroleum Engineers

Utilization of Voronoi Gridding for Simulation of Heterogeneous, Discrete Fracture Networks Using Outcrop and X-Ray CT Scanning with Non Uniform Aperture Distribution of Rough Fracture Surfaces and Intersecting Fractures

Journal of Petroleum Science Research

Polymer-WAG Simulation

2014 SPE EOR Conference at Oil & Gas West Asia

Experimental Investigation of Enhanced Recovery in Unconventional Liquid Reservoirs using CO2: A Look Ahead to the Future of Unconventional EOR

Society of Petroleum Engineer

The poor rock quality and matrix permeability several orders of magnitude lower than conventional oil reservoirs observed in unconventional liquid reservoirs (ULR) still confounds the industry on the storage capacity of the rock and the possibility of enhancing recovery. The technological advances in multiple stage hydraulic fracturing and horizontal drilling have improved the overall profitability of oil shale plays by enhancing the matrix - wellbore connectivity. The combination of these technologies has become the key factor for the operators to reach economically attractive production rates in the exploitation of ULR, causing a lot of focus on their improvement. However, as the reservoir matures, primary production mechanisms no longer drive oil to the hydraulic fractures. Therefore, the need to develop enhanced recovery techniques in order to improve the displacement of the oil from the matrix, maintain profitable production rates, extend the life of the assets and increase ultimate oil recovery becomes evident. This study presents experimental results on the use of CO 2 as an EOR agent in preserved, rotary sidewall reservoir core with negligible permeability. To simulate the presence of hydraulic fractures, the ULR core was surrounded by a high permeability glass beads and packed in a core holder. The high permeability media was then saturated with CO 2 at constant pressure and temperature during the experiment. Production was monitored over this time period. The experiment was imaged using x-ray computed tomography to track saturation changes inside the core samples. The results support CO 2 as a promising EOR agent for oil shale reservoirs. Oil recovery was estimated to be between 20 to 50 % of OOIP. The analysis of the x-ray computed tomography images revealed obvious saturation changes within the ULR core as a result of CO 2 injection. A discussion about the mechanisms is presented, including diffusion and reduction in capillary forces.

Long Term Stability of Acrylamide Based Polymers during Chemically Assisted CO2 WAG EOR

Society of Petroleum Engineers

CO 2 flooding often results in poor sweep efficiency due to the high mobility ratio caused by its low viscosity. To mitigate this problem, the alternate injection of water and CO 2 slugs, known as the water-alternating-gas process (WAG), is widely applied. Recently, numerical simulation and core flood experiments indicate that the use of chemicals in the water slug may improve mobility control during WAG, thus increasing the ultimate recovery. Therefore, the study of the stability of common polymers used for EOR applications in CO 2 saturated environments becomes necessary to address the technical and economic feasibility of this process. In this paper, we report the results of two commonly applied EOR polymers, a co-polymer of acrylamide and acrylate and a co-polymer of acrylamide and ATBS . To establish a base line for comparison, parallel experiments were conducted in two different oxygen free environments: one with CO 2 and the other with nitrogen. Samples were hydrated and aged at reservoir temperature over 300 days. To isolate the effect of CO 2, polymer thermal and chemical degradation were reduced by stripping out dissolved oxygen and decreasing divalent cation concentration from the water. Polymer samples were removed at different times and their viscosity was measured as a function of shear rate and fitted to a power law model. The ability of the polymer solutions to retain their original viscosity over time was used to quantify polymer degradation. The results of this work show that CO 2 impacts polymer stability, causing further degradation in both polymers tested. The co-polymer of acrylamide and ATBS exhibited higher resistance to CO 2 degradation as it was able to retain 94 % of its original viscosity, compared with the co-polymer of acrylamide and acrylate which only retained 56 %. We conclude that commercial polymers can be used during chemically assisted CO 2 WAG when low divalent cation water is used at a reservoir temperature of 122 F.

Long Term Stability of Acrylamide Based Polymers during Chemically Assisted CO2 WAG EOR

Society of Petroleum Engineers

CO 2 flooding often results in poor sweep efficiency due to the high mobility ratio caused by its low viscosity. To mitigate this problem, the alternate injection of water and CO 2 slugs, known as the water-alternating-gas process (WAG), is widely applied. Recently, numerical simulation and core flood experiments indicate that the use of chemicals in the water slug may improve mobility control during WAG, thus increasing the ultimate recovery. Therefore, the study of the stability of common polymers used for EOR applications in CO 2 saturated environments becomes necessary to address the technical and economic feasibility of this process. In this paper, we report the results of two commonly applied EOR polymers, a co-polymer of acrylamide and acrylate and a co-polymer of acrylamide and ATBS . To establish a base line for comparison, parallel experiments were conducted in two different oxygen free environments: one with CO 2 and the other with nitrogen. Samples were hydrated and aged at reservoir temperature over 300 days. To isolate the effect of CO 2, polymer thermal and chemical degradation were reduced by stripping out dissolved oxygen and decreasing divalent cation concentration from the water. Polymer samples were removed at different times and their viscosity was measured as a function of shear rate and fitted to a power law model. The ability of the polymer solutions to retain their original viscosity over time was used to quantify polymer degradation. The results of this work show that CO 2 impacts polymer stability, causing further degradation in both polymers tested. The co-polymer of acrylamide and ATBS exhibited higher resistance to CO 2 degradation as it was able to retain 94 % of its original viscosity, compared with the co-polymer of acrylamide and acrylate which only retained 56 %. We conclude that commercial polymers can be used during chemically assisted CO 2 WAG when low divalent cation water is used at a reservoir temperature of 122 F.

Asphaltene Gradients and Tar Mat Formation via Downhole Fluid Analysis and Novel Asphaltene Science

Rio Oil & Gas Expo and Conference

Mullins, O.C., Zuo, J., Freed, D., Elshahawi, H., Dong, C., Pfeiffer, T., and Schechter, D.: “Asphaltene Gradients and Tar Mat Formation via Downhole Fluid Analysis and Novel Asphaltene Science”, Paper IBP 3242-10 Presented at the 2010 Rio Oil & Gas Expo and Conference held at Rio de Janeiro, Brazil, Sept 13-16, 2010.

Impact of Surfactants for Wettability Alteration in Stimulation Fluids and the Potential for Surfactant EOR in Unconventional Liquid Reservoirs

Society of Petroleum Engineers

Utilization of Voronoi Gridding for Simulation of Heterogeneous, Discrete Fracture Networks Using Outcrop and X-Ray CT Scanning with Non Uniform Aperture Distribution of Rough Fracture Surfaces and Intersecting Fractures

Journal of Petroleum Science Research

Polymer-WAG Simulation

2014 SPE EOR Conference at Oil & Gas West Asia

Experimental Investigation of Enhanced Recovery in Unconventional Liquid Reservoirs using CO2: A Look Ahead to the Future of Unconventional EOR

Society of Petroleum Engineer

The poor rock quality and matrix permeability several orders of magnitude lower than conventional oil reservoirs observed in unconventional liquid reservoirs (ULR) still confounds the industry on the storage capacity of the rock and the possibility of enhancing recovery. The technological advances in multiple stage hydraulic fracturing and horizontal drilling have improved the overall profitability of oil shale plays by enhancing the matrix - wellbore connectivity. The combination of these technologies has become the key factor for the operators to reach economically attractive production rates in the exploitation of ULR, causing a lot of focus on their improvement. However, as the reservoir matures, primary production mechanisms no longer drive oil to the hydraulic fractures. Therefore, the need to develop enhanced recovery techniques in order to improve the displacement of the oil from the matrix, maintain profitable production rates, extend the life of the assets and increase ultimate oil recovery becomes evident. This study presents experimental results on the use of CO 2 as an EOR agent in preserved, rotary sidewall reservoir core with negligible permeability. To simulate the presence of hydraulic fractures, the ULR core was surrounded by a high permeability glass beads and packed in a core holder. The high permeability media was then saturated with CO 2 at constant pressure and temperature during the experiment. Production was monitored over this time period. The experiment was imaged using x-ray computed tomography to track saturation changes inside the core samples. The results support CO 2 as a promising EOR agent for oil shale reservoirs. Oil recovery was estimated to be between 20 to 50 % of OOIP. The analysis of the x-ray computed tomography images revealed obvious saturation changes within the ULR core as a result of CO 2 injection. A discussion about the mechanisms is presented, including diffusion and reduction in capillary forces.

Investigating the Effect of Improved Fracture Conductivity on Production Performance of Hydraulic Fractured Wells through Field Case Studies and Numerical Simulations

2014 SPE Hydrocarbon, Economics, and Evaluation Symposium

Long Term Stability of Acrylamide Based Polymers during Chemically Assisted CO2 WAG EOR

Society of Petroleum Engineers

CO 2 flooding often results in poor sweep efficiency due to the high mobility ratio caused by its low viscosity. To mitigate this problem, the alternate injection of water and CO 2 slugs, known as the water-alternating-gas process (WAG), is widely applied. Recently, numerical simulation and core flood experiments indicate that the use of chemicals in the water slug may improve mobility control during WAG, thus increasing the ultimate recovery. Therefore, the study of the stability of common polymers used for EOR applications in CO 2 saturated environments becomes necessary to address the technical and economic feasibility of this process. In this paper, we report the results of two commonly applied EOR polymers, a co-polymer of acrylamide and acrylate and a co-polymer of acrylamide and ATBS . To establish a base line for comparison, parallel experiments were conducted in two different oxygen free environments: one with CO 2 and the other with nitrogen. Samples were hydrated and aged at reservoir temperature over 300 days. To isolate the effect of CO 2, polymer thermal and chemical degradation were reduced by stripping out dissolved oxygen and decreasing divalent cation concentration from the water. Polymer samples were removed at different times and their viscosity was measured as a function of shear rate and fitted to a power law model. The ability of the polymer solutions to retain their original viscosity over time was used to quantify polymer degradation. The results of this work show that CO 2 impacts polymer stability, causing further degradation in both polymers tested. The co-polymer of acrylamide and ATBS exhibited higher resistance to CO 2 degradation as it was able to retain 94 % of its original viscosity, compared with the co-polymer of acrylamide and acrylate which only retained 56 %. We conclude that commercial polymers can be used during chemically assisted CO 2 WAG when low divalent cation water is used at a reservoir temperature of 122 F.

Long Term Stability of Acrylamide Based Polymers during Chemically Assisted CO2 WAG EOR

Society of Petroleum Engineers

CO 2 flooding often results in poor sweep efficiency due to the high mobility ratio caused by its low viscosity. To mitigate this problem, the alternate injection of water and CO 2 slugs, known as the water-alternating-gas process (WAG), is widely applied. Recently, numerical simulation and core flood experiments indicate that the use of chemicals in the water slug may improve mobility control during WAG, thus increasing the ultimate recovery. Therefore, the study of the stability of common polymers used for EOR applications in CO 2 saturated environments becomes necessary to address the technical and economic feasibility of this process. In this paper, we report the results of two commonly applied EOR polymers, a co-polymer of acrylamide and acrylate and a co-polymer of acrylamide and ATBS . To establish a base line for comparison, parallel experiments were conducted in two different oxygen free environments: one with CO 2 and the other with nitrogen. Samples were hydrated and aged at reservoir temperature over 300 days. To isolate the effect of CO 2, polymer thermal and chemical degradation were reduced by stripping out dissolved oxygen and decreasing divalent cation concentration from the water. Polymer samples were removed at different times and their viscosity was measured as a function of shear rate and fitted to a power law model. The ability of the polymer solutions to retain their original viscosity over time was used to quantify polymer degradation. The results of this work show that CO 2 impacts polymer stability, causing further degradation in both polymers tested. The co-polymer of acrylamide and ATBS exhibited higher resistance to CO 2 degradation as it was able to retain 94 % of its original viscosity, compared with the co-polymer of acrylamide and acrylate which only retained 56 %. We conclude that commercial polymers can be used during chemically assisted CO 2 WAG when low divalent cation water is used at a reservoir temperature of 122 F.

Asphaltene Gradients and Tar Mat Formation via Downhole Fluid Analysis and Novel Asphaltene Science

Rio Oil & Gas Expo and Conference

Mullins, O.C., Zuo, J., Freed, D., Elshahawi, H., Dong, C., Pfeiffer, T., and Schechter, D.: “Asphaltene Gradients and Tar Mat Formation via Downhole Fluid Analysis and Novel Asphaltene Science”, Paper IBP 3242-10 Presented at the 2010 Rio Oil & Gas Expo and Conference held at Rio de Janeiro, Brazil, Sept 13-16, 2010.

Impact of Surfactants for Wettability Alteration in Stimulation Fluids and the Potential for Surfactant EOR in Unconventional Liquid Reservoirs

Society of Petroleum Engineers

Utilization of Voronoi Gridding for Simulation of Heterogeneous, Discrete Fracture Networks Using Outcrop and X-Ray CT Scanning with Non Uniform Aperture Distribution of Rough Fracture Surfaces and Intersecting Fractures

Journal of Petroleum Science Research

Polymer-WAG Simulation

2014 SPE EOR Conference at Oil & Gas West Asia

Experimental Investigation of Enhanced Recovery in Unconventional Liquid Reservoirs using CO2: A Look Ahead to the Future of Unconventional EOR

Society of Petroleum Engineer

The poor rock quality and matrix permeability several orders of magnitude lower than conventional oil reservoirs observed in unconventional liquid reservoirs (ULR) still confounds the industry on the storage capacity of the rock and the possibility of enhancing recovery. The technological advances in multiple stage hydraulic fracturing and horizontal drilling have improved the overall profitability of oil shale plays by enhancing the matrix - wellbore connectivity. The combination of these technologies has become the key factor for the operators to reach economically attractive production rates in the exploitation of ULR, causing a lot of focus on their improvement. However, as the reservoir matures, primary production mechanisms no longer drive oil to the hydraulic fractures. Therefore, the need to develop enhanced recovery techniques in order to improve the displacement of the oil from the matrix, maintain profitable production rates, extend the life of the assets and increase ultimate oil recovery becomes evident. This study presents experimental results on the use of CO 2 as an EOR agent in preserved, rotary sidewall reservoir core with negligible permeability. To simulate the presence of hydraulic fractures, the ULR core was surrounded by a high permeability glass beads and packed in a core holder. The high permeability media was then saturated with CO 2 at constant pressure and temperature during the experiment. Production was monitored over this time period. The experiment was imaged using x-ray computed tomography to track saturation changes inside the core samples. The results support CO 2 as a promising EOR agent for oil shale reservoirs. Oil recovery was estimated to be between 20 to 50 % of OOIP. The analysis of the x-ray computed tomography images revealed obvious saturation changes within the ULR core as a result of CO 2 injection. A discussion about the mechanisms is presented, including diffusion and reduction in capillary forces.

Investigating the Effect of Improved Fracture Conductivity on Production Performance of Hydraulic Fractured Wells through Field Case Studies and Numerical Simulations

2014 SPE Hydrocarbon, Economics, and Evaluation Symposium

Optimization-Based Unstructured Meshing Algorithms for Simulation of Hydraulically and Naturally Fractured Reservoirs with Variable Distribution of Fracture Aperture, Spacing, Length and Strike

Society of Petroleum Engineers

Long Term Stability of Acrylamide Based Polymers during Chemically Assisted CO2 WAG EOR

Society of Petroleum Engineers

CO 2 flooding often results in poor sweep efficiency due to the high mobility ratio caused by its low viscosity. To mitigate this problem, the alternate injection of water and CO 2 slugs, known as the water-alternating-gas process (WAG), is widely applied. Recently, numerical simulation and core flood experiments indicate that the use of chemicals in the water slug may improve mobility control during WAG, thus increasing the ultimate recovery. Therefore, the study of the stability of common polymers used for EOR applications in CO 2 saturated environments becomes necessary to address the technical and economic feasibility of this process. In this paper, we report the results of two commonly applied EOR polymers, a co-polymer of acrylamide and acrylate and a co-polymer of acrylamide and ATBS . To establish a base line for comparison, parallel experiments were conducted in two different oxygen free environments: one with CO 2 and the other with nitrogen. Samples were hydrated and aged at reservoir temperature over 300 days. To isolate the effect of CO 2, polymer thermal and chemical degradation were reduced by stripping out dissolved oxygen and decreasing divalent cation concentration from the water. Polymer samples were removed at different times and their viscosity was measured as a function of shear rate and fitted to a power law model. The ability of the polymer solutions to retain their original viscosity over time was used to quantify polymer degradation. The results of this work show that CO 2 impacts polymer stability, causing further degradation in both polymers tested. The co-polymer of acrylamide and ATBS exhibited higher resistance to CO 2 degradation as it was able to retain 94 % of its original viscosity, compared with the co-polymer of acrylamide and acrylate which only retained 56 %. We conclude that commercial polymers can be used during chemically assisted CO 2 WAG when low divalent cation water is used at a reservoir temperature of 122 F.

Long Term Stability of Acrylamide Based Polymers during Chemically Assisted CO2 WAG EOR

Society of Petroleum Engineers

CO 2 flooding often results in poor sweep efficiency due to the high mobility ratio caused by its low viscosity. To mitigate this problem, the alternate injection of water and CO 2 slugs, known as the water-alternating-gas process (WAG), is widely applied. Recently, numerical simulation and core flood experiments indicate that the use of chemicals in the water slug may improve mobility control during WAG, thus increasing the ultimate recovery. Therefore, the study of the stability of common polymers used for EOR applications in CO 2 saturated environments becomes necessary to address the technical and economic feasibility of this process. In this paper, we report the results of two commonly applied EOR polymers, a co-polymer of acrylamide and acrylate and a co-polymer of acrylamide and ATBS . To establish a base line for comparison, parallel experiments were conducted in two different oxygen free environments: one with CO 2 and the other with nitrogen. Samples were hydrated and aged at reservoir temperature over 300 days. To isolate the effect of CO 2, polymer thermal and chemical degradation were reduced by stripping out dissolved oxygen and decreasing divalent cation concentration from the water. Polymer samples were removed at different times and their viscosity was measured as a function of shear rate and fitted to a power law model. The ability of the polymer solutions to retain their original viscosity over time was used to quantify polymer degradation. The results of this work show that CO 2 impacts polymer stability, causing further degradation in both polymers tested. The co-polymer of acrylamide and ATBS exhibited higher resistance to CO 2 degradation as it was able to retain 94 % of its original viscosity, compared with the co-polymer of acrylamide and acrylate which only retained 56 %. We conclude that commercial polymers can be used during chemically assisted CO 2 WAG when low divalent cation water is used at a reservoir temperature of 122 F.

Asphaltene Gradients and Tar Mat Formation via Downhole Fluid Analysis and Novel Asphaltene Science

Rio Oil & Gas Expo and Conference

Mullins, O.C., Zuo, J., Freed, D., Elshahawi, H., Dong, C., Pfeiffer, T., and Schechter, D.: “Asphaltene Gradients and Tar Mat Formation via Downhole Fluid Analysis and Novel Asphaltene Science”, Paper IBP 3242-10 Presented at the 2010 Rio Oil & Gas Expo and Conference held at Rio de Janeiro, Brazil, Sept 13-16, 2010.

Impact of Surfactants for Wettability Alteration in Stimulation Fluids and the Potential for Surfactant EOR in Unconventional Liquid Reservoirs

Society of Petroleum Engineers

Utilization of Voronoi Gridding for Simulation of Heterogeneous, Discrete Fracture Networks Using Outcrop and X-Ray CT Scanning with Non Uniform Aperture Distribution of Rough Fracture Surfaces and Intersecting Fractures

Journal of Petroleum Science Research

Polymer-WAG Simulation

2014 SPE EOR Conference at Oil & Gas West Asia

Experimental Investigation of Enhanced Recovery in Unconventional Liquid Reservoirs using CO2: A Look Ahead to the Future of Unconventional EOR

Society of Petroleum Engineer

The poor rock quality and matrix permeability several orders of magnitude lower than conventional oil reservoirs observed in unconventional liquid reservoirs (ULR) still confounds the industry on the storage capacity of the rock and the possibility of enhancing recovery. The technological advances in multiple stage hydraulic fracturing and horizontal drilling have improved the overall profitability of oil shale plays by enhancing the matrix - wellbore connectivity. The combination of these technologies has become the key factor for the operators to reach economically attractive production rates in the exploitation of ULR, causing a lot of focus on their improvement. However, as the reservoir matures, primary production mechanisms no longer drive oil to the hydraulic fractures. Therefore, the need to develop enhanced recovery techniques in order to improve the displacement of the oil from the matrix, maintain profitable production rates, extend the life of the assets and increase ultimate oil recovery becomes evident. This study presents experimental results on the use of CO 2 as an EOR agent in preserved, rotary sidewall reservoir core with negligible permeability. To simulate the presence of hydraulic fractures, the ULR core was surrounded by a high permeability glass beads and packed in a core holder. The high permeability media was then saturated with CO 2 at constant pressure and temperature during the experiment. Production was monitored over this time period. The experiment was imaged using x-ray computed tomography to track saturation changes inside the core samples. The results support CO 2 as a promising EOR agent for oil shale reservoirs. Oil recovery was estimated to be between 20 to 50 % of OOIP. The analysis of the x-ray computed tomography images revealed obvious saturation changes within the ULR core as a result of CO 2 injection. A discussion about the mechanisms is presented, including diffusion and reduction in capillary forces.

Investigating the Effect of Improved Fracture Conductivity on Production Performance of Hydraulic Fractured Wells through Field Case Studies and Numerical Simulations

2014 SPE Hydrocarbon, Economics, and Evaluation Symposium

Optimization-Based Unstructured Meshing Algorithms for Simulation of Hydraulically and Naturally Fractured Reservoirs with Variable Distribution of Fracture Aperture, Spacing, Length and Strike

Society of Petroleum Engineers

Estimation of Fracture Porosity of Naturally Fractured Reservoirs with No Matrix Pororsity Using Fractal Discrete Fracture Networks

SPE Reservoir Evaluation & Engineering