Water Shutoff at Ultralow Temperatures Using Organically Crosslinked Polymer Gels

Reddy, B.R.; Crespo, Freddy; Eoff, Larry

doi:10.2118/153155-ms

Cited by 21 publications

(20 citation statements)

References 13 publications

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“…The gelation time is a function of salinity, polymer and cross-linker concentrations and temperature (Marfo et al 2015). (Reddy et al 2012) developed correlations for gelation time as a function of salinity for polyacrylamide polymer and polyamide crosslinker showing a linear relationship. The gelation time increases with an increase in salinity because the common ions decrease the nucleophilic capacity (Salehi et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Gelation behavior as a function of concentration of sodium thiosulfate for PAM gels cross-linked with chromium

Al‐Hajri

Mahmood

Akbari

et al. 2018

J Petrol Explor Prod Technol

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Existing reducing agents for cross-linking polymers are expensive and toxic and mostly limited for water shut off applications. A gelation study was performed on a safer, cheaper, more soluble, and short-lived gel by cross-linking polyacrylamide and chromium as a cross-linking agent using a rheometer and bead-pack porous media. The effect of concentration of sodium thiosulfate as the reducing agent was investigated to determine conditions for optimum yield strength and the gelation time and behavior which has never been published before. For a fixed minimum concentration (for the gel to form) of polyacrylamide and sodium dichromate, the gel yield strength vs. sodium thiosulfate concentration showed a somewhat bell-shaped curve initially increasing, reaching a peak at 2000 ppm, and then starting to decrease. The gelation formed by sodium thiosulfate was comparatively weak and short lived as compared to the ones formed by other reducing agents. Gel started to form instantaneously, reached a peak in 2 h, began to decrease, and then stabilized at 40 cp. The mobility reduction trends were similar to the yield strength curve. The short-lived gel could be useful to improve the waterflood mobility ratio far away from the wellbore without compromising on ease of injectivity.

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Section: Introductionmentioning

confidence: 99%

Gelation behavior as a function of concentration of sodium thiosulfate for PAM gels cross-linked with chromium

Al‐Hajri

Mahmood

Akbari

et al. 2018

J Petrol Explor Prod Technol

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“…Produced water cost the petroleum industry about $45 billion in 2002 [5,6], and this could be on the increase with development of additional wells. High water cut comes with its associated problems such as corrosion, sand production, scale formation and loss of productivity [1,[7][8][9]. This occurrence is common with mature fields [10].…”

Section: Introductionmentioning

confidence: 99%

“…These equations showed that increasing the temperature shortened the gelation time of organically crosslinked gels. Reddy [9] developed correlations for gelation time as a function of degree of salinity of mixing fluid for KCl and NaCl. Their findings indicated a linear relation between gelation time and the salt concentration.…”

Section: Introductionmentioning

confidence: 99%

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

Sa¹,

Appah²,

Joel³

et al. 2016

J Pet Environ Biotechnol

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Water production is one of the major challenges in the petroleum industry, especially brown fields and water drive reservoirs. Water production can weaken the cementation of sand grains, thereby rendering formations partially or completely unconsolidated. This in turn initiates fines migration and aggravates safety concerns. The gelation time is an important characteristic of water-shutoff systems and it is influenced by different parameters. The gelation time gives an indication of the time required for a gel to transit from free flowing fluid to solid or semi-solid gel making it difficult to pump. Organically cross-linked gels have numerous applications in the industry such as shutoff systems. They are used to control water and gas production in oil wells. The effect of cross-linker concentration, temperature and brine concentration on the gelation time of an organically crosslinked system was studied. Based on the experimental results a mathematical model was developed for predicting the gelation time of the water-shutoff system. The results showed that temperature had the highest impact on the gelation time of the water-shutoff system with an effect estimate of (-2.292). The brine concentration of the mix water recorded the lowest impact with an effect estimate of 0.2083 and the interaction between cross-linker concentration and brine concentration of mix water had neutral impact. A predictable and effective water-shutoff system has been developed with an excellent initial viscosity which can easily be pumped and applied to solve water production and its associated problems. The gelation time of organically crosslinked water-shutoff system can be optimised in water control operations using this model and the effect estimates of these parameters.

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“…In these low temperature applications, gelant reaction and gelstrength-development rates are significantly lower compared to traditional encountered reservoir temperatures; this may yield long gelation times and weaker formed gels. Reddy et al (2012) discussed an HPAM/polyamine-crosslinker (organically crosslinked polymer-based) water shutoff gelant that may provide sufficient gelation times at temperatures lower than 80°F. Such gelants could be optimized with regards to gelation times development of rigid gels using activator chemicals and retarders as well as polymer/crosslinker ratios for the specific filed applications.…”

Section: Introductionmentioning

confidence: 99%

Polymers and Polymer-Based Gelants for Improved Oil Recovery and Water Control Applications in Naturally Fractured Chalk Formations

Hatzignatiou

Giske

Stavland

2016

Day 1 Wed, April 20, 2016

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Water flooding of naturally fractured carbonate (NFC) formations always poses several challenges related to formation sweep, oil recovery efficiency and rate of extraction from matrix blocks, and water management. The presence of natural fractures decreases formation sweep, delays oil recovery rates, and often yields high injector/producer conductive paths which increase produced water cuts with undesirable impacts on fluids production from technical point of view (ranging from lifting difficulties to well stop flowing) as well as economic one (produced water separation, cleaning, and re-injection).Downhole and deep-reservoir fluids management becomes important to addressing or reducing negative oil production effects in NFC formations. Injected fluid diversion away from well-established high-conductivity flow paths will be extremely beneficial to (a) sweep previously unswept formation regions, (b) reduce circulation of injected water, and (c) improve the oil recovery rate and ultimate recovery factors. Injected fluid diversion gels, used in such applications, are normally based on a polymer/crosslinker mixture designed to gel at a given distance /location away from a treated well. However, HSE regulations and/or surface facilities requirements may not permit in certain occasions the use of such chemical systems that have been tested and successfully field-applied previously.In this work, existing commercial polymer and polymer-based chemicals that could be used for water management is NFC reservoirs are screened and evaluated in the laboratory. Several testing bulk-and core-based techniques have been used to achieve this goal with the selected chemicals undergone thorough investigation of their filterability, injectivity, gelation time, gel strength, gel shrinkage, and impact on oil production.Injection of high and low molecular weight HPAM polymers into fractured cores does not hinder the oil production mechanism in chalk formations yielding a lower oil recovery rate but comparable ultimate recoveries with water injection. The environmental friendly polymer (Polymer B) gelant is ЉinconsistentЉ related to the formation of gel; when it gels, the quality of the formed gel is poor and provide no resistance to a post-treatment water injection. The non-environmentally friendly polymer (Polymer A) gelant worked consistently concerning gelation and yielded good quality, strong gels that can withstand post-treatment applied pressures during water injection.

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Water Shutoff at Ultralow Temperatures Using Organically Crosslinked Polymer Gels

Cited by 21 publications

References 13 publications

Gelation behavior as a function of concentration of sodium thiosulfate for PAM gels cross-linked with chromium

Gelation behavior as a function of concentration of sodium thiosulfate for PAM gels cross-linked with chromium

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

Polymers and Polymer-Based Gelants for Improved Oil Recovery and Water Control Applications in Naturally Fractured Chalk Formations

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