Modelling Gelation Time of Organically Cross-linked Water-shutoff Systems for Oil Wells

Presenting a suitable hydrogel for water shutoff in Iranian oil field is based on gelation time and gel strength. Rheological behavior of gel was the main purpose of this research. To determine the gelation time, thermal stability and gel strength a plan of bottle tests were conducted by using the central composite design method with two factors. The hydrogels composed of AN125VLM and chromium triacetate as copolymer and crosslinker, respectively were recorded for 8 weeks. Furthermore, the consistency modulus of the gels was measured by amplitude sweep tests using the Paar-Physica universal spectrometer, model MCR501. A hydrogel with 26,339 ppm concentration of copolymer and 0.12 ratio of crosslinker/copolymer and also gelation time of 2 days was selected as the optimal one. Also, it showed the maximum value of consistency modulus of 31,900 Pa among the other samples, tremendously, which showed the highest resistance against external stress. To ensure the gel strength among different effective parameters on the gel in porous media, a plan of rheological experiments were carried out. A 12 Run Plackett-Burman design was used for screening the eight parameters of NaCl, CaCl2, KCl and MgCl2 concentrations, temperature, pH, sodium lactate and nanoclay while keeping the optimal hydrogel component constant. Finally, it was found that temperature was the most effective parameter to control gelation time and also pH had negligible effect on the gelation time of this optimal gel.

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Controlling Gelation Time and Microgel Size for Water Shutoff

Journal of Petroleum Technology ◽

10.2118/0301-0051-jpt ◽

2001 ◽

Vol 53 (03) ◽

pp. 51-52 ◽

Cited By ~ 1

Author(s):

Dennis Denney

Keyword(s):

Gelation Time ◽

Water Shutoff

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A Nano Method for a Big Challenge: Nanosilica-Based Sealing System for Water Shutoff

10.2118/204840-ms ◽

2021 ◽

Author(s):

Ayman Almohsin ◽

Jin Hung ◽

Mohammed Alabdrabalnabi ◽

Mohammed Sherief

Keyword(s):

Chemical Treatment ◽

Fractured Reservoirs ◽

Gelation Time ◽

Cost Effective ◽

Economic Life ◽

Narrow Particle Size Distribution ◽

Water Production ◽

Water Shutoff ◽

Sandstone Rock ◽

Wide Range

Abstract Minimizing unwanted water production from oil wells is highly required in the petroleum industry. This would lead to improved economic life of mature wells that involve new and innovative technologies. Nanosilica-based sealing fluid has been developed to address problems associated with unwanted water production. The objective of this work is to evaluate a newly developed novel water shutoff system based on nanosilica over a wide range of parameters. This modified nanosilica has a smooth, spherical shape, and are present in a narrow particle size distribution. Therefore, it can be used for water management in different water production mechanisms including high permeability streak, wormhole, and fractured reservoirs. A systematic evaluation of novel nanosilica/activator for water shutoff purposes requires the examination of the chemical properties before, during, and after gelation at given reservoir conditions. These properties are solution initial viscosity, gelation time, injectivity, and strength of the formed gel against applied external forces in different flooding systems. This paper details a promising method to control undesired water production using eco-friendly, cost-effective nanosilica. Experimental results revealed that nanosilica initially exhibited a low viscosity and hence providing a significant advantage in terms of mixing and pumping requirements. Nanosilica gelation time, which is a critical factor in placement of injected-chemical treatment, can be tailored by adjusting the activator concentration to match field requirements at the desired temperature. In addition, core flood tests were conducted in carbonate core plugs, Berea sandstone rock, and artificially fractured (metal tube) to investigate the performance of the chemical treatment. Flow tests clearly indicated that the water production significantly dropped in all tested types of rocks. The environmental scanning electron microscope (SEM) results showed the presence of SiO-rich compounds suggesting that the tested nanosilica product filled the porous media; therefore, it blocked the whole core plug. A novel cost-effective sealant that uses nanotechnology to block the near wellbore region has been developed. The performance and methods controlling its propagation rate into a porous medium will be presented. Based on the outcomes, it must be emphasized that these trivial particles have a promising application in the oil reservoir for water shutoff purposes.

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Polymer Systems for Water Shutoff and Profile Modification: A Review Over the Last Decade

SPE Journal ◽

10.2118/163100-pa ◽

2013 ◽

Vol 19 (01) ◽

pp. 135-149 ◽

Cited By ~ 93

Author(s):

Khalid Saad El-Karsani ◽

Ghaithan A. Al-Muntasheri ◽

Ibnelwaleed A. Hussein

Keyword(s):

Oil And Gas ◽

Water Injection ◽

Gelation Time ◽

Field Application ◽

Injection Wells ◽

Polyelectrolyte Complexes ◽

Polymer Systems ◽

Water Shutoff ◽

Wide Range ◽

Hydrolyzed Polyacrylamide

Summary Unwanted water production is a serious issue in oil- and gas-producing wells. It causes corrosion, scale, and loss of productivity. One method of treating this problem is to chemically reduce unwanted water. This paper discusses the use of polymer systems for this purpose and presents a thorough review of available literature over the last decade. In this paper, field-application data for various polymer systems are summarized over the range of 40 to 150°C (104 to 302°F). These applications cover a wide range of permeabilities from 20 to 2,720 md in sandstone and carbonate reservoirs around the globe. Moreover, the review revealed that the last decade of developments can be categorized into two major types. The first type is polymer gels for total water shutoff in the near-wellbore region, in which a polymer is crosslinked with either an organic or an inorganic crosslinker. The second type is concerned with deep treatment of water-injection wells diverting fluids away from high-permeability zones (thief zones). These thief zones take most of the injected water, which results in a large amount of unrecovered oil. For the total-blocking gels, various systems were identified, such as polyurethane resins, chromium (Cr3+) crosslinking terpolymers, Cr3+ crosslinking foamed partially hydrolyzed polyacrylamide (PHPA), and nanoparticle polyelectrolyte complexes (PECs) sequestering Cr3+ for elongation of its gelation time with PHPA. In addition, polyethylenimine (PEI) was identified to crosslink various polyacrylamide- (PAM-) based polymers. The Petróleos de Venezuela S.A. (PDVSA) Research and Development Center developed a PAM-based thermally stable polymer and an organic crosslinker. The system is applicable for a wide temperature range from 50 to 160°C (130 to 320°F). For the deep modification of water-injection profiles in water-injection wells, two systems were identified: microspheres prepared from PAM monomers crosslinked with N,N′-methylenebisacrylamide and microspheres produced by crosslinking 2-acrylamido-2-methylpropane sulfonic acid (AMPS) with diacrylamides and methacrylamides of diamines (thermally activated microparticles known as Bright Water). This paper highlights all major developments in these areas.

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Gelation Behavior of Polyacrylamide Reinforced with Nano-Silica for Water Shutoff Treatment in Oil Field

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.307.252 ◽

2020 ◽

Vol 307 ◽

pp. 252-257

Author(s):

Nurhazwane Abdul Fadil ◽

Sonny Irawan ◽

Nur Amelia Mohd Isa ◽

Siti Rohaida Shafian

Keyword(s):

Gelation Time ◽

Silica Content ◽

Oil Field ◽

Nano Silica ◽

Water Shutoff ◽

Silica Concentration ◽

Gelation Behavior ◽

Hydrolyzed Polyacrylamide ◽

Placement Depth ◽

Gel System

Polyacrylamide gel system is widely been used in oilfield for water shutoff treatment. Gelation behavior such as proper gelation time provides a basic guideline on gel placement depth in reservoir layers. In this study, the gelation behavior of partially hydrolyzed polyacrylamide crosslinked with chromium(III) acetate (PHPA/Cr3+) reinforced with nano-silica was studied in term of gelation time and gel stability. The gelation time of PHPA/Cr3+ gel could be controlled with the addition of nano-silica where the gel has shown a delay in gelation time at low concentration of nano-silica. At 0.3 wt.% of nano-silica concentration, the gelation time has shown two times delay compared to the original gel system. The gel at the formulations of 0.7 wt.% and 1.0 wt.% nano-silica content remained stable with H code after 24 hours observation.

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