Experimental assessment of brine and/or CO2 leakage through well cements at reservoir conditions

Bachu, Stefan; Bennion, D.B.

doi:10.1016/j.ijggc.2008.11.002

Cited by 221 publications

(131 citation statements)

References 15 publications

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“…For example, recently concerns regarding old wells were a show stopper for a GCS project in the depleted De Lier gas field in The Netherlands (Hofstee et al 2008). Figure 7 shows the possible leakage paths in an abandoned well, which include preferential flow pathways along rock-cement and casing-cement interfaces, as well as through degraded materials or materials improperly formed during the plugging processes (Gasda et al 2004;Bachu and Bennion 2009).…”

Section: Wellbore Integritymentioning

confidence: 99%

“…Radial deformation of the cement sheath is commonly caused by shrinkage during cement hydration, which might result in cracking of the cement sheath or debonding at the rock/cement or cement/casing interface, allowing for radial and vertical migration of fluids (Orlic 2009). During CO 2 injection, changes in reservoir stress and deformations acting on the well assembly will impact the hydraulic aperture of rock-cement and casingcement interfaces, the most likely pathways for potential CO 2 leakage around abandoned wells (Bachu and Bennion 2009;Tau et al 2011). Fractures, if formed in the concrete, will have a rock-fracture-like stress-dependent aperture that could be significantly impacted by coupled chemical degradation once exposed to CO 2 (Huerta et al 2009;Wigand et al 2009).…”

Section: Wellbore Integritymentioning

confidence: 99%

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The Geomechanics of CO2 Storage in Deep Sedimentary Formations

2012

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This paper provides a review of the geomechanics and modeling of geomechanics associated with geologic carbon storage (GCS), focusing on storage in deep sedimentary formations, in particular saline aquifers. The paper first introduces the concept of storage in deep sedimentary formations, the geomechanical processes and issues related with such an operation, and the relevant geomechanical modeling tools. This is followed by a more detailed review of geomechanical aspects, including reservoir stressstrain and microseismicity, well integrity, caprock sealing performance, and the potential for fault reactivation and notable (felt) seismic events. Geomechanical observations at current GCS field deploy-

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Section: Wellbore Integritymentioning

confidence: 99%

Section: Wellbore Integritymentioning

confidence: 99%

The Geomechanics of CO2 Storage in Deep Sedimentary Formations

2012

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“…For assessment of the risk of CO 2 leakage from storage sites, wellbore integrity and quality of the casing annulus were recently investigated by experimental (field and lab scale) studies [Bachu and Bennion, 2009;Celia et al, 2009;Crow et al, 2010;Liteanu and Spiers, 2010] and using theoretical analyses [Checkai, 2012;Tao and Bryant, 2014]. Bachu and Bennion [2009] conducted a series of laboratory experiments on cement samples representing the annular space between the casing and the formation.…”

Section: 1002/2014wr016146mentioning

confidence: 99%

“…Bachu and Bennion [2009] conducted a series of laboratory experiments on cement samples representing the annular space between the casing and the formation. They emplaced a Portland class ''G'' cement (a commonly used cement for oil & gas wells) in an annular space with inside and outside diameters of about 40 and 70 mm, respectively, and a length of about 100 mm.…”

Section: 1002/2014wr016146mentioning

confidence: 99%

Numerical investigation of methane and formation fluid leakage along the casing of a decommissioned shale gas well

Nowamooz

Lemieux

Molson

et al. 2015

Water Resources Research

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Methane and brine leakage rates and associated time scales along the cemented casing of a hypothetical decommissioned shale gas well have been assessed with a multiphase flow and multicomponent numerical model. The conceptual model used for the simulations assumes that the target shale formation is 200 m thick, overlain by a 750 m thick caprock, which is in turn overlain by a 50 m thick surficial sand aquifer, the 1000 m geological sequence being intersected by a fully penetrating borehole. This succession of geological units is representative of the region targeted for shale gas exploration in the St. Lawrence Lowlands (Qu ebec, Canada). The simulations aimed at assessing the impact of well casing cementation quality on methane and brine leakage at the base of a surficial aquifer. The leakage of fluids can subsequently lead to the contamination of groundwater resources and/or, in the case of methane migration to ground surface, to an increase in greenhouse gas emissions. The minimum reported surface casing vent flow (measured at ground level) for shale gas wells in Quebec (0.01 m 3 /d) is used as a reference to evaluate the impact of well casing cementation quality on methane and brine migration. The simulations suggest that an adequately cemented borehole (with a casing annulus permeability k c 1 mD) can prevent methane and brine leakage over a time scale of up to 100 years. However, a poorly cemented borehole (k c ! 10 mD) could yield methane leakage rates at the base of an aquifer ranging from 0.04 m 3 /d to more than 100 m 3 /d, depending on the permeability of the target shale gas formation after abandonment and on the quantity of mobile gas in the formation. These values are compatible with surface casing vent flows reported for shale gas wells in the St. Lawrence Lowlands (Quebec, Canada). The simulated travel time of methane from the target shale formation to the surficial aquifer is between a few months and 30 years, depending on cementation quality and hydrodynamic properties of the casing annulus. Simulated longterm brine leakage rates after 100 years for poorly cemented boreholes are on the order of 10 25 m 3 /d (10 mL/d) to 10 23 m 3 /d (1 L/d). Based on scoping calculations with a well-mixed aquifer model, these rates are unlikely to have a major impact on groundwater quality in a confined aquifer since they would only increase the chloride concentration in a pristine aquifer to 1 mg/L, which is significantly below the commonly recommended aesthetic objective of 250 mg/L for chloride.

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“…Bachu and Bennion (Bachu and Bennion, 2009) tested the permeability change of good-quality cement samples subjected to 90 days of flow with CO 2 saturated brine, at 15 MPa and 65 ℃. Cement permeability dropped rapidly and remained almost constant thereafter, most likely as a result of CO 2 exsolution due to the pressure drop along the flow path.…”

Section: Summary Of Reseach Work About Carbonation Of Cement Based Mamentioning

confidence: 99%

Reactive transport modeling of CO2 through cementitious materials under CO2 geological storage conditions

Shen

2013

International Journal of Greenhouse Gas Control

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RésuméUn modèle de transport réactif est proposé pour simuler la réactivité des matériaux à base de ciment en contact avec une saumure saturée en CO 2 et/ou le CO 2 supercritique (CO 2 sc) dans les conditions de stockage géologique du CO 2 . Un code a été développé pour résoudre simultanément le transport et la chimie par une approche globale couplée, compte tenu de l'effet de la température et de la pression.La variabilité des propriétés du CO 2 sc avec la pression et la température, telles que la solubilité dans l'eau, la densité et la viscosité sont pris en compte. On suppose que tous les processus chimiques sont en équilibre thermodynamique. Les réactions de dissolution et de précipitation de la portlandite (CH) et Ce modèle est en mesure de simuler les processus de carbonatation des matériaux à base de ciment, dans des conditions à la fois saturés et insaturés, dans une large plage de concentration de CO 2 , de température et de pression. Plusieurs expériences, rapportées dans la littérature, sont simulées en utilisant divers types de conditions aux limites: (i) solutions saturées ou non en CO 2 et carbonate de calcium, (ii) gas supercritique de CO 2 . Les prédictions sont comparées avec les observations expérimentales. Certains II phénomènes observés expérimentalement peuvent être également expliqués par le modèle. Mots-clés:Carbonatation, CO 2 supercritique, Transports, Ciment, C-S-H, Décalcification, Pression, Température, Stockage du CO 2 . AbstractA reactive transport model is proposed to simulate the reactivity of cement based material in contact with CO 2 -saturated brine and supercritical CO 2 (scCO 2 ) under CO 2 geological storage conditions. This code is developed to solve simultaneously transport and chemistry by a global coupled approach, considering the effect of temperature and pressure.The variability of scCO 2 properties with pressure and temperature, such as solubility in water, density and viscosity are taken into account. It is assumed that all chemical processes are in thermodynamical equilibrium. Dissolution and precipitation reactions for portlandite (CH) and calcite (CC) are described by mass action laws and threshold of ion activity products in order to account for complete dissolved minerals. A chemical kinetics for the dissolution and precipitation of CH and CC is introduced to facilitate numerical convergence. One properly chosen variable is able to capture the precipitation and dissolution of the relevant phase. A generalization of the mass action law is developed and applied to calcium silicate hydrates (C-S-H) to take into account the continuous variation (decrease) of the Ca/Si ratio during the dissolution reaction of C-S-H. The changes in porosity and microstructure induced by the precipitation and dissolution reactions are also taken into account.Couplings between transport equations and chemical reactions are treated thanks to five mass balance equations written for each atom (Ca, Si, C, K, Cl) as well as one equation for charge balance and one for the total mass. Ion tran...

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Experimental assessment of brine and/or CO2 leakage through well cements at reservoir conditions

Cited by 221 publications

References 15 publications

The Geomechanics of CO2 Storage in Deep Sedimentary Formations

The Geomechanics of CO2 Storage in Deep Sedimentary Formations

Numerical investigation of methane and formation fluid leakage along the casing of a decommissioned shale gas well

Reactive transport modeling of CO2 through cementitious materials under CO2 geological storage conditions

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