Evaluation of Polymer-Assisted Carbonated Water Injection in Sandstone Reservoir: Absorption Kinetics, Rheology, and Oil Recovery Results

Abstract

The efficacy of carbonated water injection (CWI) is associated with weak CO2 absorption in water, and the resulting CWI does not meet the requirements of controlled CO2 mobility and enhanced oil recovery (EOR). High molecular weight oilfield polymer, e.g., polyacrylamide (PAM), is water-soluble and often used in water shut-off and mobility control applications. Thus, in this study, PAM, with concentrations (0.5, 1, and 2 g/L), as a viscosifier is used to improve the CO2 absorption capacity of water for possible implementation in CWI applications. PAM with intermediate concentration (1 g/L) was favorable for enhanced CO2 absorption with a retention period of 4 days in water. With high PAM concentration (2.0 g/L), CO2 absorption reduced and gas in the form of globules moderately absorbed in the upper layers of P-1 solution, resulting in a significant amount of aqueous phase left unabsorbed by CO2. At high PAM concentration, enough number of PAM chains were available to interact with CO2 and, as a result, solution received premature gelling that resisted further entry of CO2. The effect of stirring on CO2 absorption showed that the rate of stirring increases the amount of CO2 absorbed in P-1 solution. These observations were supported by rheological data which showed that CO2 absorption reduced the viscosity of the P-1 solution, and the decrease in viscosity is directly proportional to the amount of CO2 absorbed. Finally, oil recovery experiments were performed using P-1 solution with and without CO2 and compared with water. The oil recovery was found to be higher for P-1 solution prepared with 600 rpm. Thus, this study highlights the application of relatively common oilfield polymer PAM (⩽ 1 g/L) for enhanced CO2 absorption and improved oil recovery than conventional CWI, which recommends use of polymer-enhanced carbonated water injection (PE-CWI) in oil and gas industry.

Impact of Low Salinity Water Injection on CO2 Storage and Oil Recovery for Improved CO2 Utilization

“…The fluids (water, saline solutions, crude oil, CO 2 and chase water) were injected using the syringe pumps at very low flow rates to ensure that viscous fingering does not take place. The oil recovery experiments were carried out by following the well-established procedure (Chaturvedi et al, 2019a;Goswami et al, 2018;Sharma et al, 2016). To establish 100% water saturation in sand-pack, water was injected at a constant flow rate of 30 ml/hr.…”

“…At high salt concentration, negligible CO 2 loading was observed and hence, the time to breakthrough was least. This can be further understood by observing the role of residual water in the efficacy of CO 2 injection process which performs comparatively worse in the presence of higher connate water as more CO 2 is trapped with water, instead of oil (Chaturvedi et al, 2019a). The use of saline water reduces some of the affinity of CO 2 for water and promotes higher participation of CO 2 in oil recovery.…”

“…The efforts seeking its atmospheric reduction are receiving widespread attention in recent times. One of the methods is to utilize CO 2 on large scale for underground storage and the oil recovery optimization, where CO 2 is expected to create enough miscibility with trapped oil and mobilize its lighter hydrocarbon components towards surface (Chaturvedi et al, 2018;Chaturvedi et al, 2019a;Honarvar et al, 2017;Ruidiaz et al, 2018). However, CO 2 being the lighter gas than the crude oil, results in its early breakthrough due to bypassing and the viscous fingering effects.…”

Development of a Green and Sustainable Nanofluid Based on Carbon Dots with Sensing Capability for Enhanced Oil Recovery

“…Reduction in the interfacial tension (IFT) to form the emulsion layer in the brine/crude oil interface; wettability alteration to change the reservoir rock character from oil-wet to water-wet; disjoining pressure to spread the nanofluid onto the rock surface; and log jamming to temporarily clog small porous throats by aggregation of nanoparticles are listed as the more discussed mechanisms proposed with the nanofluid to enhance oil recovery. 25,32 High-potential but limited studies of CD applications in EOR motivated us to develop CDs with dual functions: as an equipment-free sensing agent to monitor the water flow path in oil reservoirs and a flooding agent to improve oil sweep efficiency and displacement. Herein, a microwave method using urea and citric acid as a nontoxic and low-cost precursor is employed to synthesize blue-emissive CDs (b-CDs) with high quantum yield in 5 min.…”

“…Beneficial nanometer size, less than 10 nm, accelerates the CD flow in the tiny pores without clogging or destructive interactions with rocks to sweep oil from inaccessible sites or heterogeneous reservoirs. − With regard to that, the applications of nanofluids involving CDs in unconventional reservoirs with nano/mesopores seem to be the most important. − Such a quantum size with a high surface area enables significant oil recovery by manipulating and engineering oil–rock–water ternary systems with different mechanisms. Reduction in the interfacial tension (IFT) to form the emulsion layer in the brine/crude oil interface; wettability alteration to change the reservoir rock character from oil-wet to water-wet; disjoining pressure to spread the nanofluid onto the rock surface; and log jamming to temporarily clog small porous throats by aggregation of nanoparticles are listed as the more discussed mechanisms proposed with the nanofluid to enhance oil recovery. , …”