Water Shutoff Research Articles

Application of Renewable Natural Materials for Gas and Water Shutoff Processes in Oil Wells

We propose a complex sealing compound for increasing the efficiency of shutoff operations based on natural materials processing for materials such as sand, peat, rice, and husks. We studied the influence of mechanical activation processes on the mechanical and rheological properties of the developed sealants. Through mechanochemical activation, sand dissolution in a low-concentrated alkali solution was possible, and gelling the resulting sodium silicate while reinforcing it with undissolved sand particles to obtain a sealant composition. We used this approach to produce a hybrid sealing compound based on activated rice husks with up to 20% biogenic silicon dioxide combined with mechanically activated peat: the maximum shear strain of the hybrid sealant was 27.7 ± 1.7 Pa. We produced hydrogels based on sodium silicate, polyacrylamide, and chromium acetate, reinforced with mechanically activated rice husks. We studied the sealants’ rheological and filtration properties and observed the respective viscoplastic and viscoelastic properties. An increase in the dispersion concentration from 0 to 0.5% increased the maximum strain value of undestroyed hydrogel’s structure in the range 50–91 Pa and the maximum shear strain from 104 to 128 Pa. The high residual resistance factor values of the ideal fracture model make the natural and plant-renewable raw materials very promising for repair and sealing work.

Technology Focus: Water Management (December 2022)

2022 has presented many challenges—not just inflation. Lowering water levels at Lake Mead and Lake Powell resulted in water crises in many states. Globally, many rivers dried, and that brought to surface over-5,000-year-old archeological artifacts that had been buried. An United Nations report says that nearly 4 billion people (approximately 60% of the world population) face water crises at least for a month every year. Despite all these admonishments, water—an essential raw material in industrial sector and a vital resource for human living—could be handled with more value and respect. The dollar value of water usage is much lower in the US compared with other regions, where it is more than twice its purchased value. The last 30 years or so have seen scientists and environmentalists apply conscientious use of technologies that focused on making water resources sustainable—chemistries that help us treat water, and intuitive and intelligent technologies that minimize need and maximize its purpose and benefit, remove contaminants, and ready it for repurposing. We can agree that awareness is universal, but when it comes to enforcing the actions needed to protect the resource as sustainable, questions about scalability and economic feasibility of many of the novel technologies arise. The three papers chosen for publication share different approaches to chemically managing high-salinity produced water through commercially viable approaches. The identification of processes to treat high salinity levels and the approaches to alter and control the process make the papers not only good for discussion but also practical for all players, big and small. The introduction of chemistries that are tagged and measurable positively influence discharge restrictions in different regions and could be exploited to stretch water reuse and the dollar value of water. The advent of smart sensors, probes, handhelds such as portable X-ray fluorescence and X-ray diffraction sensors, and machine learning make the treatment and reuse of high-saline water feasible to alleviate the water crisis. Technologies have advanced to lower the energy consumption and usage cost of membrane separation most commonly used in the water-reuse sector. The use of fresh water by the industry could be reduced significantly with the adaptation of some or all the smart technologies available today. The industry and the public are at a crossroads today, fighting for the right to use water. Governments are struggling to keep the balance and make the scarcest resource available to both sides. Let there not be another Akkadian empire that becomes extinct because of water. Recommended additional reading at OnePetro: www.onepetro.org. SPE 200171 Optimizing Waterflood Performance in Mature Fields Using Autonomous Inflow Control Valve Technology by Sufyan Shihab, Petroleum Development Oman, et al. SPE 209256 Improved Reverse-Osmosis Membranes for Treating Produced Water by Rich Franks, Nitto-Hydranautics, et al. SPE 204840 A Nano Method for a Big Challenge: Nanosilica-Based Sealing System for Water Shutoff by Ayman Almohsin, Saudi Aramco, et al.

Chemically crosslinked polyvinyl alcohol for water shut‐off and conformance control treatments during oil production: The effect of silica nanoparticles

AbstractPolyvinyl alcohol (PVA) is a synthetic commercial polymer with the inherent hydrophilicity, thermal and chemical resistance, ecofriendly, and a high anti‐fouling potential making it an attractive choice for water treatment applications, but has been less studied for oil and gas industry applications. On the other hands, nowadays nanotechnology has gained an important space within most core areas in upstream oil and gas operations. The present work, first PVA at various concentrations, was added to 5 wt% NaCl solution and then, crosslinked by formaldehyde 37% at two different concentration ratios. To compare, a nanocomposite hydrogel was fabricated in the same way with 1 wt% silica nanoparticles (NPs). Contact angle and filtration test were performed to confirm the ability of PVA hydrogel and nanocomposite hydrogel for oil and water adsorption. Following this, a rheology measurement was made to realize the gelation time of samples and their performance for water shutoff applications. Finally, an experimental flooding setup was designed to inject the fluids into carbonate plugs in order to estimate of oil and water effective permeability, and oil recovery factor (RF) before and after the PVA hydrogel and nanocomposite hydrogel injection. Both samples wettability tests showed a super‐hydrophilic state for brine droplets and neutral state for synthetic oil droplets by using nanocomposite hydrogel. The flooding tests revealed that the PVA hydrogel was clogged the plug with blocking efficiency of 32.83% for water effective permeability and 14.60% for oil effective permeability. This value was calculated to be 50.37% for water effective permeability and 31.36% for oil effective permeability in the case of nanocomposite hydrogel injection. Oil RF was also reported to be 64.58% after injecting PVA hydrogel which was higher than nanocomposite hydrogel injection with RF of 52.08%.

Unlocking the potentials of gel conformance for water shutoff in fractured reservoirs: Favorable attributes of the double network gel for enhancing oil recovery

The double-network prepared with an in-situ monomer gel and a fast-crosslinked Cr(III) gel is introduced to develop a thixotropic and high-strength gel (THSG), which is found to have many advantages over the traditional gels. The THSG gel demonstrates remarkable thermal stability, and no syneresis is observed after 12 months with high salinity brine (95,500 mg/L). Moreover, the SEM and XRD results indicate that the gel is intercalated into the lamellar structures of Na-MMT, where the gel can form a uniform and compact structure. In addition, the THSG gel has an excellent swelling behavior, even in the high salinity brine. In the slim tube experiments, the THSG gel exhibits high rupture pressure and improves blocking capacity after being ruptured. The core flooding results show that a layer of gel filter cake is formed on the face of the fracture, which may be promoted by a high matrix permeability, a small aperture fracture, and a high injection rate. After the gel treatment, the fracture can be completely blocked by the THSG gel. It is found that a high incremental oil recovery (65.3%) can be achieved when the fracture was completely blocked, compared to 40.2% if the gel is ruptured. Although the swelling of ruptured gel can improve oil recovery, part of the injected brine may be channeled through the gel-filled fractures, resulting in a decrease in the sweep efficiency. Therefore, the improved blocking ability by gel swelling (e.g., in fresh water) may be less efficient to contribute to an enhancement of oil recovery. It is also found that the pressure gradient and residual resistance factor to water (Frrw) are higher if the matrix is less permeable, indicating that the fractured reservoir with lower matrix permeability may require a higher gel strength for treatment. The findings of this study may provide novel insights on designing robust double network gels for water shutoff in fractured reservoirs.

Optimization of Hydrolyzed Polyacrylamide/Chromium (III)-Acetate Gel-Plugging Process after Preflush Crosslinker in Fractured Extralow Permeability Reservoir at Moderate Temperature

SummaryHydrolyzed polyacrylamide/chromium III [HPAM/Cr (III)]-acetate gel treatment is an effective way for conformance control and water shutoff in various mature reservoirs around the world. However, it encounters severe challenges in the fractured extralow permeability reservoirs with the performance varying between success and failure when channeling caused by through-type fracture exists. The through-type fracture channel that connected injection to production is formed by the connection of hydraulic and natural fractures. This research takes the extralow permeability reservoir in the Ordos Basin as the background, and under the characterization of HPAM/Cr (III)-acetate gel, the effect of a preflush crosslinker on improving gel-plugging performance was studied via experiment, and the corresponding gel-plugging process was optimized. Experimental results showed that the preflush crosslinker could effectively improve the blocking strength and stability of HPAM/Cr (III)-acetate gel for through-type, large-opening fractures. Moreover, a high-quality “gel wall” was formed based on the preflush crosslinker; it worked as a barrier within the fracture and was the key to successfully blocking the millimeter-opening fracture. Under the experimental conditions, the optimized plugging process was as follows: The crosslinker was preflushed 24 hours in advance, and the gelant was injected in three slugs, with the volume of the first slug being 0.5 pore volume (PV). A field trial conducted in Ansai Oil Field demonstrated the potential of HPAM/Cr (III)-acetate gel and its plugging capability of optimized plugging method based on the preflush crosslinker to block through-type water channeling. This research provides valuable experimental data and theoretical guidance for conformance control and water shutoff of HPAM/Cr (III)-acetate gel treatment in fractured extralow permeability reservoirs.

Thermo-/pH-Dual-Sensitive PEG/PAMAM Nanogel: Reaction Dynamics and Plugging Application of CO2 Channeling.

Smart hydrogels, owing to their exceptional viscoelastic and deformable capacity in response to environmental stimulation involving temperature and pH, have been successfully applied in oilfields for purposes such as water and/or gas shutoff treatments. However, the CO2 breakthrough problem in low permeability reservoirs has not been well solved. In this work, a rheological method-based Avrami dynamics model and Dickinson dynamics model were employed to investigate the dynamic gelation process of thermo-/pH-dual-sensitive PEG/PAMAM nanogels to further our understanding of the microstructure of their gelation and pertinence plugging application. Plugging experiments were performed by alternating injections of CO2 and hydrogel solution in a slug type on three fractured low permeability cores with a backpressure of 13 MPa. The nanogels presented a secondary growth pattern from three to one dimension from micrometer to nanometer size with a morphological transformation from a sphere to an irregular ellipsoid or disk shape. The phase transition temperature was 50 °C, and the phase transition pH was 10. If both or either were below these values, the hydrogel swelled; otherwise, it shrank. Plugging results show that the plugging efficiency was higher than 99%. The maximum breakthrough pressure was 19.93 MPa, and the corresponding residual pressure remained 17.64 MPa for a 10 mD core, exhibiting great plugging performance and high residual resistance after being broken through by CO2.

Polymer Gels Used in Oil-Gas Drilling and Production Engineering.

Polymer gels are widely used in oil–gas drilling and production engineering for the purposes of conformance control, water shutoff, fracturing, lost circulation control, etc. Here, the progress in research on three kinds of polymer gels, including the in situ crosslinked polymer gel, the pre-crosslinked polymer gel and the physically crosslinked polymer gel, are systematically reviewed in terms of the gel compositions, crosslinking principles and properties. Moreover, the advantages and disadvantages of the three kinds of polymer gels are also comparatively discussed. The types, characteristics and action mechanisms of the polymer gels used in oil-gas drilling and production engineering are systematically analyzed. Depending on the crosslinking mechanism, in situ crosslinked polymer gels can be divided into free-radical-based monomer crosslinked gels, ionic-bond-based metal cross-linked gels and covalent-bond-based organic crosslinked gels. Surface crosslinked polymer gels are divided into two types based on their size and gel particle preparation method, including pre-crosslinked gel particles and polymer gel microspheres. Physically crosslinked polymer gels are mainly divided into hydrogen-bonded gels, hydrophobic association gels and electrostatic interaction gels depending on the application conditions of the oil–gas drilling and production engineering processes. In the field of oil–gas drilling engineering, the polymer gels are mainly used as drilling fluids, plugging agents and lost circulation materials, and polymer gels are an important material that are utilized for profile control, water shutoff, chemical flooding and fracturing. Finally, the research potential of polymer gels in oil–gas drilling and production engineering is proposed. The temperature resistance, salinity resistance, gelation strength and environmental friendliness of polymer gels should be further improved in order to meet the future technical requirements of oil–gas drilling and production.

A selective water control and gas augmentation method based on APR gel

Water production will seriously affect the economics of gas well in the development of oil field. However, the conventional water shutoff agent is easy to block the gas flow channel at the same time of plugging the water. In this paper, a temperature and salt resistant polymer gel system composed of acrylamide/acryloyl morpholine/vinylpyrrolidone terpolymer (APR) and polyethyleneimine/modified alumina nanoparticle cross-linker was developed. At the same time, a selective water control and gas augmentation method based on APR gel was established. The effect of gel composition on its performance was mainly studied, and the water & gas shutoff performance in harsh environment was also researched by sandpack flow experiment. The gelation time could be controlled within 2–14 h by adjusting the concentration of the polymer, cross-linker, and deoxidant. In addition, the dehydration rate of the gel was only 2.6% after 180 days heat aging at 107 °C and 230,000 mg/L mineralization. The scanning electron microscope (SEM) showed that the uniform distribution of the network structure resulted in the gel with excellent stability in harsh environments. Sand filling experiments indicated that the plugging rate of gel for sand filling models with different permeability was all above 90% in harsh environment (107 ℃, 230000 mg/L salinity). Besides, laboratory experiments have illustrated that the injection pattern of the gel has a significant influence on its water & gas shutoff performance. Injecting 0.5PV gel solution first, then injecting 6PV N2, the shutoff performance of gel for water was nine times as good as that of gas. The research provides technical guidance for the water shutoff of high-temperature and high-salt gas reservoirs.

Synthesis of a low viscosity amphoteric polyacrylamide and its application in oilfield profile control

AbstractA low viscosity amphoteric polyacrylamide (LHPAM) was synthesized with Acrylamide and a Cationic etherifying agent. FTIR, SEM, and EDS all suggest that it successfully synthesized a new material. It can be demonstrated from TG and DSC that the temperature resistance of LHPAM is higher than that of partially hydrolyzed polyacrylamide (HPAM) and it can be found from ultraviolet–visible spectrophotometer that the flocculability of LHPAM is stronger than that of HPAM. The viscosity testing shows that the viscosity of LHPAM is greater than that of HPAM at the beginning, but the viscosity of LHPAM has been ultimately lower than that of HPAM after 1d. In addition, LHPAM reacts with Cr3+ to form a gel with an interpenetrating network structure, while HPAM is a gel with a comb‐shaped system, and the gelation time of LHPAM is longer than that of HPAM. However, the final gelation strength is the same. The final flow experiment shows that the plugging rates of LHPAM and HPAM are greater than 95%, but the resistance coefficient of LHPAM is smaller than that of HPAM. This study expands the application of HPAM in profile control and water shutoff, which is of great significance for enhanced oil recovery.

New insights into the DPR mechanism of elastic energy released by polymer gel for enhanced oil recovery

Polymer gel was widely used as water shutoff agent in mature oil fields. And the results of single-phase plugging experiments show that the plugging rate of the polymer gel to the oil phase is lower than that of the water phase. However, the disproportionate permeability reduction (DPR) mechanism of polymer gels still remains controversial. In this paper, we used four gel formulations including polyethyleneimine (PEI) and phenol-formaldehyde crosslinked gel with and without adding laponite to investigate the effect of gel elastic property on the water shutoff mechanism. The result of sand pack flooding experiments shown that the gel with higher elastic modulus has better effects on decreasing water cut and increasing oil recovery. After adding laponite, the elastic modulus of phenol-formaldehyde crosslinked gel increased from 64.2 Pa to 192 Pa, and the elastic modulus of PEI crosslinked gel increased from 27.4 Pa to 36.5 Pa. Compared to the phenol-formaldehyde-HAPM gel, the oil recovery of laponite-phenol-formaldehyde-HPAM gel increased by 5.2% and the maximum water cut decreased by 8.3%. Besides, comparing with PEI-HPAM gel, the oil recovery of laponite-PEI-HPAM gel increased by 2.7% and the water cut dropped by 27.8%. In the meanwhile, the laponite-phenol-formaldehyde-HPAM gel with higher elastic modulus obviously swells in the formation water but almost remains constant in oil at 105°C. The mass of gel soaked in the formation water increased from 42 g to 96 g and the gel volume increased by 300% within 48 hours. This study improves the understanding of the DPR mechanism of polymer gel for water shutoff.

Substantiation of In Situ Water Shut-Off Technology in Carbonate Oil Reservoirs

The efficient development of carbonate oil deposits with excessive fissuring is a current challenge. Uneven and rapid well stream watering is considered as one of the factors that make the process of the development of carbon deposits more complicated. The purpose of the research is to diagnose and evaluate the mechanisms of well stream watering for carbon deposits and find applicable technology to prevent it. An overview of in situ water shut-off technologies was carried out. A description of the main materials used for water shut-off is presented, and selective methods are studied in more detail. A carbonate basin of an oil field is selected as the object of investigation. The geological and physical characteristics of this deposit are given. Analysis of possible causes and sources of water cut of the fluid is made according to the technique of K.S. Chan, under which the main reason for the watering of the well production is the breakthrough of formation and injection water through a system of highly permeable natural fractures and channels. Matrixes of applicability of in situ water shut-off technologies and polymer compositions are made. The composition based on carboxymethyl cellulose for in situ water shut-off is selected for the chosen deposit.

Graded regulation technology for enhanced oil recovery and water shutoff in pore-cavity-fracture carbonate reservoirs

• Clarified the types of chemical agents for graded regulation of pore-vug-fracture carbonate reservoirs. • Plugging effect and oil–water selectivity of gel and nanospheres. • Wetting modifiers improve the efficiency of injection water to wash the oil are investigated. • Comprehensively discussed the synergistic mechanism of profile control and water shutoff and improving the efficiency of oil washing with injected water. Although a single type of chemical agent (eg, gels, microspheres, surfactants, etc.) has achieved some effects in enhanced oil recovery of carbonate reservoirs, for pore-cavity-fracture carbonate reservoirs, the use of a single type of chemical agent does not perform well. The main objective of this study is to study the effect of different types of chemical agents in enhanced oil recovery of complex carbonate reservoirs. In order to determine the screening principle of chemical agents, the types of water channeling in the North Troyes reservoir were analyzed. For complex fractures, step by step plugging, multi-agent and multi-slug comprehensive intervention is carried out to ensure the plugging of high-permeability channels and inhibit the seepage of large channels. It can plug channeling fracture channel, adjust secondary dominant channel and reduce matrix flow resistance, so as to expand macroscopic swept volume and improve microscopic water flooding efficiency. The results show that it is difficult to comprehensively control water channeling in pore-cave-fracture carbonate reservoir, and the reservoir heterogeneity in the test area can be improved by mixing different types of control and flooding agents and carrying out deep profile control. The plugging rate of gel is 97.18 %, and the oil–water selection ratio is 0.45 in fractured core; the expansion rate of nano - microspheres is more than 3 times; the wetting modifier can improve the imbibition oil displacement efficiency by 14.76%, and the test result shown that nano - microspheres and wetting modifier have good synergistic oil displacement effect. The field application result shown that daily oil production of oil well in the test area increased by 5.0 m 3 /d and the daily water rate decreased by 19.0% compared with that before the control flooding. The findings of this study can help for better understanding of enhanced oil recovery in pore-cave-fracture carbonate reservoir.

Types and Performances of Polymer Gels for Oil-Gas Drilling and Production: A Review.

Polymer gels with suitable viscoelasticity and deformability have been widely used for formation plugging and lost circulation control, profile control, and water shutoff. This article systematically reviews the research progress on the preparation principle, temperature resistance, salt resistance, and mechanical properties of the ground and in situ crosslinked polymer gels for oil-gas drilling and production engineering. Then, it comparatively analyzes the applicable conditions of the two types of polymer gel. To expand the application range of polymer gels in response to the harsh formation environments (e.g., high temperature and high salinity), we reviewed strategies for increasing the high temperature resistance, high salt resistance, and rheological/mechanical strengths of polymer gels. This article provides theoretical and technical references for developing and optimizing polymer gels suitable for oil-gas drilling and production.

Comprehensive Review of Polymer and Polymer Gel Treatments for Natural Gas-Related Conformance Control.

Conformance problems often exist in natural gas-related activities, resulting in excessive water production from natural gas production wells and/or excessive natural gas production from oil production wells. Several mechanical and chemical solutions were reported in the literature to mitigate the conformance problems. Among the chemical solutions, two classes of materials, namely polymer gels and water-soluble polymers, have been mostly reported. These systems have been mainly reviewed in several studies for their applications as water shutoff treatments for oil production wells. Natural gas production wells exhibit different characteristics and have different properties which could impact the performance of the chemical solutions. However, there has not been any work done on reviewing the applications of these systems for the challenging natural gas-related shutoff treatments. This study provides a comprehensive review of the laboratory evaluation and field applications of these systems used for water control in natural gas production wells and gas shutoff in oil production wells, respectively. The first part of the paper reviews the in-situ polymer gel systems, where both organically and inorganically crosslinked systems are discussed. The second part presents the water-soluble polymers with a focus on their disproportionate permeability reduction feature for controlling water in gas production wells. The review paper provides insights into the reservoir conditions, treatment design and intervention, and the success rate of the systems applied. Furthermore, the outcomes of the paper will provide knowledge regarding the limitations of the existing technologies, current challenges, and potential paths forwards.

The chemistry insight: epoxy sealant as an alternative remedial operation for well integrity

Abstract Epoxy resin is commonly used in the oil and gas industry due to its excellent toughness, low shrinkage, good adhesive strength, and relatively good thermal resistance. It is used for water shutoff, zonal isolation, cementing, enhanced oil recovery, and preventing leakage in wells. This paper reviews the chemistry aspect of using an epoxy resin system as a sealant to prevent well leakage and it offers insights into the chemistry of the epoxy resin system, as applied in previous studies. The paper also unveils the reasons for the application of this system from the chemistry perspective, allowing this aspect to be better understood. Success in the investigated cases depended on the formulation design. The epoxide and hydroxyl functional groups have been found to contribute substantially to the excellent performance of the sealant system. Furthermore, the amine curing agent triggers the abrupt reaction of the oxirane ring to stabilise when the cured sealant is perfectly applied. Based on the findings, it is suggested that other types of epoxies, namely epoxidised oils, require further study. Finally, in terms of safety and sustainable energy, it is suggested that more curing agent and diluent studies are undertaken.

Insight into the Synergic Effect of Partially Hydrolyzed Polyacrylamide and Nanosilica on Sodium Silicate Sealant Gel System for Water Shutoff Applications

Insight into the Synergic Effect of Partially Hydrolyzed Polyacrylamide and Nanosilica on Sodium Silicate Sealant Gel System for Water Shutoff Applications

Residual Oil Distribution Pattern in a Fault-Solution Carbonate Reservoir and Countermeasures to Improve Oil Development Effectiveness

Because of the strong random distribution of fractures and caves, fault-solution carbonate reservoirs exhibit significantly different flow mechanisms and development methods from conventional carbonate reservoirs. Natural elastic and edge-bottom water flooding are the main processes for developing fault-solution reservoirs. The rapid decline in production and the complex residual oil distribution are major challenges for oil production. This study is aimed at (1) assessing the residual oil migration law, (2) determining the residual oil distribution characteristics, and (3) identifying the main controlling factors using numerical simulation, to provide suggestions for enhancing oil recovery. The results showed that fractures are the main channel for oil flow and the main path of bottom water coning in the fault-solution reservoirs. The channeling of bottom water along high-angle fractures is the main reason for the decline in oil production. In addition, bottom water coning and gas/water injection are the key factors affecting the distribution of residual oil, while the irregular development of fractures and caves is the main factor causing diversified distribution patterns of the residual oil. The residual oil distribution patterns of fault-solution reservoirs include 4 types, namely, attic, bottom water rising and blocking, separated fracture-cavity, and pores near high-conductivity channel types. For tapping the potential of residual oil, several approaches can be used, namely, deploying new wells or using sidetracking of old wells in the loft and the separated fracture-cavity reservoirs. In addition, the attic residual oil type can also be developed using drainage oil recovery or gas injection for oil replacement. Liquid lift pump, water shutoff, and water cone restrain can also be used to tap residual oil from rising bottom water. Optimizing profile control and water shutoff measures and adjusting the injection and production relationship can be effective approaches for developing residual oil in the pores and cracks beside the high diversion channel.

Sensitivity analysis of parameters affecting nano-polymer solution for water shutoff in carbonate rocks

Excessive water production impacts the economics of petroleum reservoir and often leads to their premature shut-in. Production of high saline water represents a major corrosion for casing, tubing, flow lines, and production facilities. Polymer solution has been used to control water production and to plug in high-temperature reservoirs. Most of these polymer solutions consist of polyacrylamide-based polymer and an organic or inorganic cross linker. Polyethylene mine has been used as an organic cross-linked for polyacrylamide. Literature reported that polyethylene mine can also form ringing gels with polyacrylamide copolymers in addition to polyacrylamide concentration. In this study, nano-chemical solutions has been prepared and studied in detail for their efficacy at reservoir condition. The compositions of the nano-chemicals mainly consisted of polyacrylamide mixed with nano particles, cement, coated-clay and polyethylene mine as cross-linker. The aim of using nano particles and coated-clay was to control gel performance and strength under the reservoir condition. Moreover, the effect of nano-chemical composition at higher temperature have been studied extensively on the gelation properties, elastic modulus, viscosity, and swelling ratio. Results showed that the elastic modulus and viscosity improve significantly with the increasing nano particle concentration. Coated-clay can control the gelation time as clay swallows and absorbs more formation water in the target zone, when its thin coated film breaks down, lesser water production can be predicted. Cited as: Soka, S., Sidiq, H. Sensitivity analysis of parameters affecting nano-polymer solution for water shutoff in carbonate rocks. Advances in Geo-Energy Research, 2022, 6(3): 230-240. https://doi.org/10.46690/ager.2022.03.06

Synthesis and optimization of bentonite enforced poly (acrylamide/co- sodium dodecylbenzensulfonate) preformed particle gels for conformance control in high salinity reservoirs

Water production in the matured oil reservoir is a big concern to the petroleum industry because of increased oil production costs and water discharge problems. In the present study, Poly (Acrylamide/Co- Sodium dodecylbenzene sulfonate (SDBS)) preformed particle gels (PPG) was synthesized, characterized, and evaluated as a conformance control agent for the high-temperature and high-salinity conditions. The rheological properties, along with the chemical and thermal stability of the synthesized PPGs were enhanced through optimization by integrating new functional groups (SDBS) into their structure to resist as high as 10% salinity and 100 °C. A succession of 16 experiments with varying amounts of acrylamide, SDBS and bentonite concentrations were conducted to obtain the optimum composition to yield the best PPG. The results showed improved swelling ratio, gel strength, rheological properties and thermal stability of the PPGs synthesized. A Delay in degradation of bentonite impregnated PPGs was observed from 37 days to 120 days @100 °C, whereas the increase in water residual resistance factor was 184.6%. The use of low-cost bentonite clay as a new material, in place of costly nanoparticles in nano-PPG, would like to reduce to cost of effective water shutoff to reduce water production.

Analysis of the efficiency of water shutoff technology in production wells

Analysis of the efficiency of water shutoff technology in production wells