Testing Advanced Sealants to Address Wellbore Seepage of Co2 Behind Casing at the Mont Terri Underground Research Laboratory

Goodman, Harvey; Espie, Tony; Minnig, Christian; Rösli, Ursula; Gisiger, Jocelyn; Roback, Robert

doi:10.2139/ssrn.3365937

Cited by 3 publications

(2 citation statements)

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“…This system swells in acidic conditions, bolstering its sealing efficacy . Recent research highlights the capability of polyacrylamide gels to obstruct large pores, diminish porous media permeability, and thereby mitigate CO 2 leakage. − Moreover, Goodman et al have demonstrated that a methyl methacrylate polymer sealing system displays impressive sealing prowess, enduring pressure gradients and expanding significantly at low pH levels. − In comparison to single-ion polymers, composite gels exhibit exceptional compounded properties. A gel system combining polyacrylamide, urotropine, and resorcinol has been proposed by Li et al, where control over the gelation time and temperature is possible.…”

Section: Introductionmentioning

confidence: 99%

“… 11 − 13 Moreover, Goodman et al have demonstrated that a methyl methacrylate polymer sealing system displays impressive sealing prowess, enduring pressure gradients and expanding significantly at low pH levels. 14 − 15 16 In comparison to single-ion polymers, composite gels exhibit exceptional compounded properties. A gel system combining polyacrylamide, urotropine, and resorcinol has been proposed by Li et al, where control over the gelation time and temperature is possible.…”

Section: Introductionmentioning

confidence: 99%

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Development and Characterization of CO₂–Responsive Intelligent Polymer Sealant

Wu,

Lou,

Zhai

et al. 2023

ACS Omega

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In this study, we present an innovative intelligent polymer sealant designed to mitigate CO 2 leakage during underground geological storage (CCUS). This sealant is formulated by cross-linking CO 2 -responsive polymers, specifically acrylamide (AM) and N-[3-(dimethylamino) propyl] methacrylamide (DMAPMA), with polyethylenimine (PEI) serving as the cross-linking agent. The polymer sealant’s characteristics were systematically investigated, varying the CO 2 -responsive polymer content (1.5 wt %) and PEI content (0.1–0.6 wt %). A comprehensive analysis encompassing the rheological properties, thermal behavior, conductivity, and microstructures was conducted. Experimental results indicate that the polymer sealant exhibits excellent injectability, rapid response kinetics, thermal stability, and robust mechanical strength. Upon encountering CO 2 , the polymer system undergoes a transition from sol to gel state, forming a surface-smooth, uniformly porous three-dimensional (3D) network skeleton structure. Remarkably, the gel’s modulus remains relatively unaffected by the shear frequency. Core fluid displacement experiments demonstrated a substantial sealing efficiency of 73.6% for CO 2 and an impressive subsequent injection water sealing rate of 96.2%, underscoring its superior sealing and migration performance. In conclusion, the proposed CO 2 -responsive gel sealant exhibits an exceptional potential for successful utilization in CCUS operations. This advancement introduces a novel avenue to enhance the effectiveness of CO 2 -responsive gel sealants, thereby contributing to the advancement of CO 2 leakage mitigation strategies in geological storage scenarios.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Development and Characterization of CO₂–Responsive Intelligent Polymer Sealant

Wu,

Lou,

Zhai

et al. 2023

ACS Omega

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Pilot Case Study of Wellbore Leakage Mitigation using pH-Triggered Polymer Gelant

Tavassoli

Shafiei

Minnig³

et al. 2019

Day 2 Wed, March 27, 2019

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Wellbore integrity is a critical subject in oil and gas production, and CO2 storage. Successful subsurface deposition of various fluids, such as CO2, depends on the integrity of the storage site. In a storage site, injection wells and pre-existing wells might leak due to over-pressurization, mechanical/chemical degradation, and/or a poor cement job, thus reducing the sealing capacity of the site. Wells that leak due to microannuli or cement fractures on the order of microns are difficult to seal with typical workover techniques. We tested a novel polymer gelant, originally developed for near borehole isolation, in a pilot experiment at Mont Terri, Switzerland to evaluate its performance in the aforementioned scenario. The polymer gel sealant was injected to seal a leaky wellbore drilled in the Opalinus Clay as a pilot test. The success of the pH-triggered polymer gel (sealant) in sealing cement fractures was previously demonstrated in laboratory coreflood experiments (Ho et al. 2016, Tavassoli et al. 2018). pH-sensitive microgels viscosify upon neutralization in contact with alkaline cement to become highly swollen gels with substantial yield stress that can block fluid flow. The leaky wellbore setup was prepared by heating-cooling cycles to induce leakage pathways in the cased and cemented wellbore. The leakage pathways are a combination of fractures in the cement and microannuli at the cement-formation interface. The exact nature of these leakage pathways can be determined by over-coring at the end of the experiment life. We used polyacrylic acid polymer (sealant) to seal these intervals. The process comprises of three stages: (1) injection of a chelating agent as the preflush to ensure a favorable environment for the polymer gel, (2) injection of polymer solution, and (3) shut-in for the polymer gelation. Then, we evaluated the short-/long-term performance of the sealant in withholding the injected fluids (formation brine and CO2 gas). The novel sealant was successfully deployed to seal the small aperture pathways of the borehole at the pilot test. We conducted performance tests using formation brine and CO2 gas to put differential pressure on the polymer gel seal. Pressure and flow rate at the specific interval were monitored during and after injection of brine and CO2. Results of performance tests after polymer injection were compared against those in the absence of the sealant. Several short-term (4 min) constant-pressure tests at different pressure levels were performed using formation brine, and no significant injection flow rate (rates were below 0.3 ml/min) was observed. The result shows more than a ten-fold drop in the injection rate compared to the case without the sealant. The polymer gel showed compressible behavior at the beginning of the short-term performance tests. Our long-term (1-week) test shows even less injectivity (~0.15 ml/min) after polymer gelation. The CO2 performance test shows only 3 bar pressure dissipation overnight after injection compared to abrupt loss of CO2 pressure in the absence of polymer gel. Sealant shows good performance even in the presence of CO2 gas with high diffusivity and acidity. Pilot test of our novel sealant proves its competency to mitigate wellbore leakage through fractured cement or debonded microannuli, where other remedy techniques are seldom effective. The effectiveness of the sealing process was successfully tested in the high-alkaline wellbore environment of formation brine in contact with cement. The results to date are encouraging and will be further analyzed once over-coring of the wellbore containing the cemented annulus occurs. The results are useful to understand the complexities of cement/wellbore interface and adjust the sealant/process to sustain the dynamic geochemical environment of the wellbore.

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Effectiveness of a Smart Hydrogel in Well Leakage Remediation

Welch

Gilbertson

Boukhalfa

et al. 2020

Day 3 Wed, October 28, 2020

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Leakage in carbon storage and hydrocarbon wells continues to be an area of concern in the development and abandonment of reservoirs. Industry need for a leakage remediation sealant that can perform in systems beyond the capability of cement squeezes has driven the development of a CO2/pH activated "smart" gel. Exploratory laboratory tests and a mock field scale well test were performed to determine the effectiveness of the smart gel. Control of the smart gel particle size distribution was demonstrated through batch synthesis experiments. Microfluidic experiments show some of the mechanisms leading to the successful sealing of an engineered fracture system. Initial and subsequent testing of the deployed smart gel in a leaky mock well completion proves the effective scale up of the smart gel sealing capability and can further drive wider adoption of this unique technology.

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Testing Advanced Sealants to Address Wellbore Seepage of Co2 Behind Casing at the Mont Terri Underground Research Laboratory

Cited by 3 publications

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Development and Characterization of CO₂–Responsive Intelligent Polymer Sealant

Development and Characterization of CO₂–Responsive Intelligent Polymer Sealant

Pilot Case Study of Wellbore Leakage Mitigation using pH-Triggered Polymer Gelant

Effectiveness of a Smart Hydrogel in Well Leakage Remediation

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Testing Advanced Sealants to Address Wellbore Seepage of Co2 Behind Casing at the Mont Terri Underground Research Laboratory

Cited by 3 publications

References 0 publications

Development and Characterization of CO2–Responsive Intelligent Polymer Sealant

Development and Characterization of CO2–Responsive Intelligent Polymer Sealant

Pilot Case Study of Wellbore Leakage Mitigation using pH-Triggered Polymer Gelant

Effectiveness of a Smart Hydrogel in Well Leakage Remediation

Contact Info

Product

Resources

About

Development and Characterization of CO₂–Responsive Intelligent Polymer Sealant

Development and Characterization of CO₂–Responsive Intelligent Polymer Sealant