Relative Permeability Modifier Research Articles

A new insight on relative permeability modifier as conformance control in carbonate reservoir

The primary issue of high-water cuts in exploiting carbonate fields poses significant challenges and requires an immediate solution. The approach to tackle the root cause of this problem is reservoir conformance control. Conventional conformance control treatments, such as polymer-based materials, are ineffective and incompatible with the unique properties of carbonate reservoirs. Textural heterogeneity in carbonate leads to heterogeneity in the distribution of storage and flow properties that may govern changes in saturation patterns. The percolation of gas-water flow in carbonate highly depends on the pore structure. Conformance control refers to managing fluid movement within a reservoir to optimize production and reduce unwanted fluid production. The major challenge of water conformance control for carbonates using chemical treatment is the compatibility of the polymer system with the rock and fluid settings. This paper reviews current research on conformance control methods, including chemical and mechanical techniques. The effectiveness of various conformance control methods was evaluated based on their ability to improve sweep efficiency, reduce water production, and increase hydrocarbon recovery in different reservoir types. The review also discusses the challenges of implementing conformance control techniques, such as formation damage and fluid mobility issues. Overall, the paper concludes that successful implementation of conformance control strategies requires a thorough understanding of reservoir characteristics and planning to ensure optimal results. The findings of this study provide valuable insights into developing effective conformance control techniques that can improve hydrocarbon recovery and optimize reservoir performance. The results of this study provide critical insight into using efficient and operationally low-risk materials to reduce water cuts in the strong water drive carbonate reservoir.

Evaluation of the polymer hydrogels as a potential relative permeability modifier

AbstractExcessive water production poses a significant challenge in the oil industry, especially in Pre‐salt carbonate reservoirs, leading to reduced oil recovery, corrosion, and well abandonment. We explore the potential of polymeric preformed particle gels (PPGs) as innovative relative permeability modifiers (RPMs) for carbonate reservoirs. RPMs involve applying polymeric hydrogels to alter reservoir wettability, reducing water flow while enhancing oil productivity. PPGs offer a promising surface‐based production alternative with improved control and minimized formation damage compared to traditional in‐situ gels. We conducted crosslinking experiments using poly(acrylamide‐acrylic acid‐2‐methyl propane sulfonate) terpolymer (AM‐AA‐AMPS) and aluminum (III) ions, assessing their impact on hydrogel properties. We also investigated the swelling behavior of these hydrogels and their interactions with rock samples. Results showed that crosslinking significantly affects PPG viscoelastic properties and swelling behavior. Adsorption tests revealed the formation of a polymeric film on rock surfaces, potentially altering wettability. Contact angle measurements demonstrated PPGs' ability to shift rock wettability, particularly in carbonate samples, from strongly oil‐wet to water‐wet conditions. This study underscores PPGs' potential as RPMs, offering valuable insights into improving oil extraction efficiency and addressing water production challenges in the industry.

Experimental investigation and numerical simulation of relative permeability modifiers during water shut-off

Relative permeability modifier (RPMs) is a water-shutoff technique that is implemented mostly in high water-producing wells when conventional mechanical isolation methods are not suitable. To optimize RPM injection treatment, numerical simulation is the most effective tool. In this study, laboratory experiments were conducted to investigate the rheology and characteristics properties of newly formulated polymer grafted bentonite (GB). Baseline GB dispersion rheological model was developed using the concept of the effective volume fraction of particles, which depends on hydrodynamic forces. The model considers the effects of the three most significant factors, namely concentration, shear rate, and temperature. GB was then tested in a coreflood to ensure effectiveness and applicability in real reservoir conditions. Coreflood results were matched using a numerical simulator and the rheology model was incorporated to reduce uncertainty and determine critical GB-related simulation parameters. Subsequently, a pilot-scale simulation, which uses the history-matched coreflood parameters, was built to predict and optimize 5-spot pattern performance. A sensitivity analysis was performed for the effect of GB volume injected, layer thickness, and permeability contrast. The results show that the viscosity equation resulting from the modeling allows appropriate correlation of the experimental data of shear stress versus shear rate with change in concentration and temperature. The simulation results reveal that the injection of GB has improved pilot-scale performance in both water-cut reduction and oil recovery. Sensitivity results indicate that the effective period of GB treatment is longer when treated in low water cut than in high water cut. However, more GB injection results in better water control.

Economic Evaluation Of Water Production Management With Rpm (Relative Permability Modifier) Treatment Based On Gross Split Contract In “Re” Well In “Dn" Field

The "RE" well in the "DN" field is an oil well produced in June 2004 with an initial water cut value of 15% as time went on there was a fairly high increase in the water cut value reaching 97% which means that it caused increased water production. and oil production decreased from 387 BOPD to 11 BOPD.
 Appropriate handling in overcoming excessive water production, one of which is by using a method that can selectively restrain water production without restraining hydrocarbon production with RPM (Relative Permeability Modifier) ​​Treatment. RPM (Relative Permeability Modifier) ​​is a type of polymer with a high molecular weight as the main molecule of RPM. RPM can be done without isolating the layer zone so that it can be injected bullhead into all layer zones to reduce water permeability.
 This final project research has been seen from increasing the rate of oil production and decreasing the water cut. The selected well is the "RE" well in the "DN" field which has an increasing water cut value and decreased oil production. Then calculate the economy using the gross split method to calculate the feasibility level of the RPM (Relative Permeability Modifier) ​​Treatment project.

Experimental Investigation and Numerical Simulation of Relative Permeability Modifiers During Water Shut-Off

Experimental Investigation and Numerical Simulation of Relative Permeability Modifiers During Water Shut-Off

Impact of prolonged water‐gas flow on the performance of polyacrylamide

AbstractExcessive water production from natural reservoirs is a major challenge in oil and gas industry. Relative permeability modifiers (RPM) are used to selectively reduce water production with minimum effect on the hydrocarbon production. This work examined the performance of polyacrylamide in terms of its water control efficiency at prolonged water‐gas flowing cycles. During each cycle, as the volume of injected water increased, the RPM demonstrated stronger performance in terms of reducing water permeability. This is attributed to the swelling of polymer layer adsorbed to the pore surfaces. Conversely, during each cycle, higher volume of gas injection led to less reduction in the gas effective permeability (PRg) which is due to polymer shrinkage. The reduction in water absolute permeability (PRw) of the treated micromodel in each injection cycle was significantly greater than the reduction in gas permeability. Interestingly, as water‐gas cycles progressed, a significant increase in water permeability reduction was observed. It is also found that polymer expansion and shrinkage are reversible. As such, the RPM performance depends on the injected fluid, injected fluid volumes and water‐gas injecting cycling. We thus conclude that that polymer swelling, and shrinkage and polymer‐gas interaction play a vital role in RPM performance.

Application of a Pickering Emulsified Polymeric Gel System as a Water Blocking Agent.

The conventional methods for controlling excess water production in oil/gas wells can be classified on the basis of the mechanism (pore-blocking mechanism and relative permeability modification) used. Gel systems developed on the basis of a pore-blocking mechanism completely block the pores and stop the flow of both oil and water, whereas a relative permeability modifier (RPM) only restricts the flow of a single phase of the fluid. The gel working on the basis of the pore-blocking mechanism is known as a total blocking gel. An invert emulsified (PAM–PEI) polymer gel is a relative permeability modifier system. The same invert emulsion system is tested as a total blocking gel system in this research work. The dual-injection technique (1st injection and 2nd injection) was used for this purpose. In this research work, the emulsion system was tested at a temperature of 105 °C. The core sections with drilled holes and fractures were used for the core flooding experiments, representing a highly fractured reservoir. The developed emulsified gel system was characterized using a dilution test, an inverted bottle test, microscopic images, and FTIR images. The emulsified polymer gel was tested using a core flooding experiment. After the 2nd injection, the postflood medical CT and micro-CT images of the core sections clearly showed the presence of two different phases in the core section, i.e., the oil phase and the gel phase. The core flooding experiment result indicates that the gel formed after the 2nd injection of the emulsion system can withstand a very high differential pressure, i.e., above 2000 psi. The gel did not allow any oil or water to be produced. Hence, the developed emulsified polymer gel system with the help of a dual-injection technique can be efficiently used as a total blocking gel for high-temperature reservoirs.

Rock/Fluid/Polymer Interaction Mechanisms: Implications for Water Shut-off Treatment

Several disproportionate permeability reduction (DPR) mechanisms have been proposed in the literature for water shutoff treatment using polymer relative permeability modifiers (RPM). However, none appear to be universally accepted. The lack of agreement may be because no single factor determines the success of DPR treatment. Moreover, there is still a lack of understanding of DPR mechanisms and the order of how these mechanisms work together. This paper provides a comprehensive review of the mechanisms behind the RPMs. We identify that sufficient polymer adsorption onto the rock surface is a primary condition for water shutoff treatment, while rock surface initial wettability and fluid–polymer–rock interaction/attraction plays a significant role in polymer adsorption. Furthermore, polymer concentration, polymer molecular weight, aging time, polymer injection volume, polymer injection rate, and reservoir temperature are also vital for polymer adsorption. After polymer adsorption, the mechanisms such as fluid segregation and wall effect help accomplish the required DPR. We also find that there is a more consistent agreement among the published studies on the order of DPR mechanisms e.g. initial rock wettability effect comes first, followed by initial segregation, adsorption wall effect (i.e., steric, lubrication, wettability alteration, and swelling/shrinkage), and then the final segregation. Depending on the RPM implementation, which depends on pore size, the polymer layer thickness can be adjusted after the placement permanently or temporarily by controlling swelling/shrinkage. The subject matter investigated in this review helps us understand the factors responsible for optimal performance of polymer solutions in controlling excess water production from hydrocarbon reservoirs—thus assisting in more efficient oil/gas production.

Further Insights into the Performance of Silylated Polyacrylamide-Based Relative Permeability Modifiers in Carbonate Reservoirs and Influencing Factors.

We have previously used surface chemistry analysis techniques to optimize the functionalization of carbonate rocks with a silylated polyacrylamide-based relative permeability modifier (RPM). The RPM is expected to selectively reduce the permeability to water in a hydrocarbon reservoir setting, resulting in a reduction in the amount of produced water while maintaining the production of oil/gas. This study will focus on using core flooding techniques with brine/crude oil under reservoir conditions (i.e., 1500 psi pore pressure and 60 °C temperature) to understand the impact of a silylated polyacrylamide-based RPM on the fluid transport properties in carbonate rocks. The effects of RPM concentration, brine salinity, rock permeability, and pore structure on permeability characteristics were studied. Scanning electron microscopy (SEM) combined with energy dispersive spectroscopy (EDX) provided visual images of the polymer adsorbed onto the rock surfaces and confirmed the attachment of the polymer on the surface of the rock pore space after treatment. The relative percentage of Si increased from 1.65 to 13.55%, and the relative percentage of N increased to 4.54%. Core flooding showed that increasing the PAM-co-AA (poly acrylamide-co-acrylic acid partial sodium salt) concentration resulted in residual resistance factors for oil (RRFoil) and brine (RRFbrine) that were greater than 1. However, there was a modest decrease in the disproportionate permeability reduction (DRP) ratio (RRFbrine/RRFoil) from 1.75 to 1.60 when the polymer concentration was increased from 0.05 to 0.1 wt %. Furthermore, the RRFbrine values decreased slightly from 120 to 62 with increasing salinity (i.e., 1–10% NaCl) because of electrostatic shielding caused by charged ions in brine and the RPM. The cross-over points of relative permeability in these four samples shifted to the right because of the larger decrease in relative water permeability compared with relative oil permeability. End-point relative permeability to water in sample C-5 decreased by 80%, showing a reduction greater than that in the sample C-2 (i.e., 74%). Kr curves indicated a stronger formation damage in sample C-1, C-2, and C-4 than in sample C-5. Rock samples with a higher initial permeability exhibited a higher RRFbrine to RRFoil ratio (i.e., 3.05) under similar test conditions. This can be attributed to a larger pore radius, which was verified by nuclear magnetic resonance (NMR) measurements. Furthermore, a detailed mechanism has been proposed to understand the effects of the RPM on fluid transport in porous carbonate cores. In this study, SEM–EDX and NMR measurements combined with core flooding tests provide insights into the performance of silylated polyacrylamide-based RPMs and benefit its future implementation in carbonate reservoirs.

Mechanistic Aspects of Polymeric Relative Permeability Modifier Adsorption onto Carbonate Rocks

Relative permeability modifiers (RPMs) are chemicals that can be injected into a reservoir to change its fluid/gas transport characteristics. For example, RPMs can reduce the relative permeability ...

Low-Salinity-Assisted Cationic Polyacrylamide Water Shutoff in Low-Permeability Sandstone Gas Reservoirs

The application of polymer-based relative permeability modifiers (RPM) in low-permeability sandstone reservoirs has long intrigued production engineers. We hypothesize that lowering salinity may ex...

Novel Relative Permeability Modifier using Polymer Grafted Nanoclay

One of the major challenges in the upstream oil and gas industry is to control and reduce high water production from a large number of oil wells. A relative permeability modifier (RPM) has been pro...

Effective Mechanisms to Relate Initial Rock Permeability to Outcome of Relative Permeability Modification

Excessive water production is becoming common in many gas reservoirs. Polymers have been used as relative permeability modifiers (RPM) to selectively reduce water production with minimum effect on the hydrocarbon phase. This manuscript reports the results of an experimental study where we examined the effect of initial rock permeability on the outcome of an RPM treatment for a gas/water system. The results show that in high-permeability rocks, the treatment may have no significant effect on either the water and gas relative permeabilities. In a moderate-permeability case, the treatment was found to reduce water relative permeability significantly but improve gas relative permeability, while in low-permeability rocks, it resulted in greater reduction in gas relative permeability than that of water. This research reveals that, in an RPM treatment, more important than thickness of the adsorbed polymer layer ( e ) is the ratio of this thickness on rock pore radius ( e r ).

Evaluation of Barium Sulfate Scale Inhibition Using Relative Permeability Modifier Polymers as Adsorption Enhancer for Mature Offshore Well Treatments in Campos Basin, Brazil

In many mature offshore fields, high water cuts and potential scale deposition are some of the toughest challenges operators need to face. Two common practices used to deal with these challenges are relative permeability modifiers (RPM) polymer injection and scale inhibitor squeeze treatments. Even though many fields face these two challenges simultaneously, little is known about concomitant application of these treatments. In this paper, the effect of applying RPM polymers prior to inhibitor squeeze in the effectiveness of the last treatment is evaluated for sandstone rocks of Campos Basin, Brazil. Sequential laboratory injections in Campos Basin rocks of commercial cationic and anionic polyacrylamide and polyaluminum chloride (PAC) as cross-linking agent were employed prior to the injection of a commercial organophosphonic acid type inhibitor for barium sulfate scale. It was found that the polymers employed are capable of reducing the permeability of porous media to water and increasing the retention time of the scale inhibitor simultaneously. The tests also indicated that the inhibitor’s longer retention time is associated with the interaction with an outer cationic layer of the cross-linking agent. The adsorption isotherms were calculated and compared with Langmuir, Freundlich, Sips, and Toth models, the last two being the most accurate in representing the adsorption system for these tests.

Numerical simulation study of factors affecting relative permeability modification for water-shutoff treatments

Polymer solutions and gels are frequently used to control excessive water production in oil and gas wells by reducing the permeability to water flow to a greater extent than to oil or gas flow (Relative Permeability Modifiers, RPM, or disproportionate permeability reduction, DPR). RPM and DPR can be used as synonymous in this study; however, specialists use RPM term for the cases in which permeability reduction is less compare to DPR. The significance of RPM agents, chemicals using in water-shutoff treatments, is that their placement does not require mechanical isolation. However, the performance of RPM treatment is still poor in field applications. This study applied numerical simulation methods to investigate the factors impacting RPM treatments on reservoir (Macroscopic) level. Furthermore, Design of Experiments (DOE) was used to rank these factors based on their influence on RPM performance (water cut reduction and oil recovery improvement).The results indicated that there are nine parameters which can enhance or downgrade the success of DPR treatments, treatments at oil/gas wells when use of DPR polymer or gel results in Disproportionate Permeability Reduction of treated formation. The performance of DPR treatment was more pronounced at low oil density, low oil viscosity, high gel penetration depth, and at high permeability heterogeneity among layers (linear flow is more dominated). However, the performance of DPR treatments was downgraded if the treatments were applied at high production flowrate, low ratio of residual resistance factor for water (Frrw) to residual resistance factor for oil (Frro), and high G-shape (crossflow indicator) values. Moreover, when the capillary forces dominate the flow (capillary-viscous number>10), RPM results were not largely encouraging due to water blocking effect. On the other side, in the viscous dominated flow, RPM performance was more pronounced. These factors which were studied in this work can promote a short-term successful remedy, a long-term successful treatment, or even a failed treatment. Some of these factors can be controlled; the operator can choose the optimum level of the parameter, like production flowrate. However, other factors cannot be controlled, but the value of this study is still increase probability of success the treatment prior to field application.

Effect of nanoparticle inclusion in fracturing fluids applied to tight gas-condensate reservoirs: Reduction of Methanol loading and the associated formation damage

Hydraulic fracturing is one of the most common stimulation operations for increasing the productivity of a well. The fracturing fluid is one of the key factors in the operation and must accomplish some special requirements and behavior. The fluid that remains inside the fracture and the reservoir after the fracturing operation is finished, causes severe damage to the proppant pack and the formation, leading to a lower efficiency of the stimulation. This study presents experimental research on adding nanoparticles to a commercial fracturing fluid commonly used for tight gas-condensate reservoirs, aiming to enhance its performance in rheological behavior and its capacity to reduce the formation damage associated with the use of fracturing fluids. Nanoparticles with mean particle sizes of 8 and 19 nm with basic and acidic surface modifications were employed for modifying a commercial fracturing fluid. Rheology tests were performed at pressure and temperature conditions of 1.38 MPa and 104 °C, respectively, for the different nanoparticles at dosages of 100 and 200 mg/L. The improvement of those properties enabled the modification of the original formulation of the fluid, reducing the amount of methanol, one of most expensive and hazardous additives, by up to 33%, and reducing the formation damage by approximately 71%. Furthermore, this modified fluid was evaluated in terms of its impact in the wettability of the rock and its relative permeability to water and oil through static (contact angle measurements) and dynamic tests (relative permeability curves). The modified fracturing fluid showed an excellent capability to improve the water-wettability of the rock and also decreased the relative water permeability by 83%. This work demonstrates the suitability of adding nanoparticles to fracturing fluid for stimulations where it is necessary to reduce the relative permeability of water, acting as a Relative Permeability Modifier (RPM) in a conformance for a fracturing operation.

Improved Oil Recovery Through Development of Gum-based Relative Permeability Modifier

Improved Oil Recovery Through Development of Gum-based Relative Permeability Modifier

A Laboratory Evaluation of a Relative Permeability Modifier for Water Production Control

Relative permeability modifier (RPM) is proven to be effective to control water production. In this study, the static adsorption and disproportionate permeability reduction of RPM were investigated. Experimental results indicate that the static adsorption of RPM on quartz sands and reservoir sands, which is in line with Langmuir adsorption isotherm, is affected by electrostatic interactions and wettability of solid surface. Adsorption on reservoir sands is far less than that on quartz sands and RPM can render the oil-wet quartz plate to be weakly water-wet plate. Physical simulation results show that RPM has good disproportionate permeability reduction effect to control water production.

Streamlines simulation of barrier fracture as a novel water shutoff technique

Excessive water production has been a problem in the oil industry for many years. To handle this problem, many research projects have focused on developing conformance control systems. Conformance fracturing, a combination of hydraulic fracturing and water control, has proven to be an effective conformance control technique. Hydraulic fracturing is now the technology of choice for increasing well productivity. The chemistry of relative permeability modifiers has also undergone extensive change; the most notable result of which has been to prolong the life of water control treatments using relative permeability modifier (RPM) polymers. The purpose of this study was to investigate the application of barrier-fracturing using streamline simulation. Barrier-fracturing is a novel idea that involves modifying the flow profile and diverting the displacing fluid by placing a fracture with essentially zero permeability deep into the reservoir. There are many ways to create a zero permeability fracture, examples of which include injection of cement or a conformance fluid into the fracture. In our study, we created several streamline simulation models to show the fidelity and validity of this innovative idea. The streamline simulation models that are presented in this paper range from a simple homogeneous reservoir to a very heterogeneous reservoir. The effect of different barrier-fracture lengths on the reservoir performance was analyzed. We also built streamline models for conventional mechanical and chemical water shutoff techniques (e.g. re-completion and RPM) to compare them with the novel barrier-fracture water shutoff technique. The resulting saturation distribution maps from the longer barrier-fracture clearly show the power of a barrier-fracture to modify flow profile and divert the displacing fluid in comparison to conventional water shutoff techniques. Barrier-fractures helped improve oil recovery by delaying water-breakthrough and eventually improving the volumetric sweep efficiency.

Synthesis and Characterization of a Novel Hydrophobically Associating Relative Permeability Modifier

A novel hydrophobically associating copolymer P (MPEGA-DMAEMA) has been synthesized by inverse emulsion polymerization, using N,N-dimethylaminoethyl methacrylate (DMAEMA) and methoxy polyethylene glycol acrylate (MPEGA) as comonomers. The synthesized copolymer has been characterized by FT-IR spectroscopy, 1H-NMR spectroscopy, scanning electron microscopy (SEM), thermal analysis (TA) and intrinsic viscosity measurement. The results reveal that P (MPEGA-DMAEMA) copolymer has been synthesized successfully. The copolymer has a smooth surface with many irregular caves, and has thermal stability above 170°C in an atmosphere of air. Reactivity ratios of DMAEMA and MPEGA are determined by Fineman-Ross method and are shown to be equal to r(DMAEMA) = 0.29 and r(MPEGA) = 2.66. Intrinsic viscosity of the hydrophobically associating copolymer reaches 282.84mL/g at 30°C. In temperature, salt and shear resistant experiments, the copolymer aqueous solution exhibits efficient anti-heat and salt resistance characteristics, and has unique rheological behavior. Coreflood experiment results show that the copolymer reduces permeability to water above 90%, while to oil under 40%, which indicates that the copolymer has obvious selectivity to water and oil.