Cement Plugs: Stability and Failure by Buoyancy-Driven Mechanism

Crawshaw, John; Frigaard, I.A.

doi:10.2118/56959-ms

Cited by 21 publications

(7 citation statements)

References 15 publications

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“…Most analyses have focused on the post-placement phase of plug cementing and on understanding the evolution of a slumping flow. That slow axial slumping flows do occur for realistic fluid physical properties can be seen in the experimental work of [5,8]. The slumping flow is approximately uni-directional, along the axis of the well, at least far from the advancing fronts.…”

Section: Introductionmentioning

confidence: 84%

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Upper bounds on the slump length in plug cementing of near-horizontal wells

Frigaard

Ngwa

2004

Journal of Non-Newtonian Fluid Mechanics

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Section: Introductionmentioning

confidence: 84%

“…[3][4][5][6][7][8], and also the fluid mechanics literature, [9][10][11][12][13]. Most analyses have focused on the post-placement phase of plug cementing and on understanding the evolution of a slumping flow.…”

Section: Introductionmentioning

confidence: 99%

Upper bounds on the slump length in plug cementing of near-horizontal wells

Frigaard

Ngwa

2004

Journal of Non-Newtonian Fluid Mechanics

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“…Calvert et al (1995) tried to define empirical relationships between hole angle, density differential between mud and slurry, and yield point of the pills, that would indicate a stability region for certain hole sizes. Crawshaw and Frigaard (1999) take a similar approach for post-placement interface stability developing a dimensionless function to better predict exchange flows. In both publications, the relationship takes a conservative approach and can be used to design pills to act as stable basements.…”

Section: Viscous Pill Designmentioning

confidence: 99%

Modified Approach Leads to Successful Off-Bottom Cementing Plugs in Highly Deviated Wells in the Caspian Sea

Isgenderov

Taoutaou

Kurawle

et al. 2015

SPE/IATMI Asia Pacific Oil &Amp; Gas Conference and Exhibition

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Certain abandonment operations require plugs to be set off-bottom in a well. The challenge in setting plugs in highly deviated wellbores lies in obtaining a competent hydraulic seal that can qualify as a barrier to any potential flow zones. Failure to achieve a good cement plug leads to increased nonproductive time (NPT) from cleanout, drillout, and setting additional plugs. Small slurry volumes, unstable fluid interfaces with respect to gravitational forces, and fluid contamination add to the complications. In the Caspian Sea abandonment operations, plug-placement simulation aided in designing cement plugs and setting procedures in inhibited seawater, water-base, or oil-base drilling fluid environments. The advanced cement plug placement simulator was used to design fluid properties and optimize volumes for plug-placement operations in highly deviated Caspian Sea wells.For successful placement, physical fluid properties and fluid mechanics were used in the advanced placement simulator; in addition to the fluid behavior, the simulation took into account well geometries, tubular dimensions, and mechanical separation devices. Various parameters affecting successful plug placement, including but not limited to, length of tailpipe, gel strengths, underdisplacement volumes, and placement procedures were input into the simulations. Balanced cement plug placement is widely practiced by many operators. In the literature, it has been shown that when smaller diameter tubing or tailpipe is run on the bottom of drillpipe, the assumption that all fluids both inside and outside the drillpipe will remain in hydrostatic equilibrium is wrong. In this study, advanced placement modeling illustrated that an initially balanced cement plug may become unbalanced while pulling a cement string with tailpipe out of the hole. Multiple abandonment operations performed in Caspian Sea wells provided key lessons for wellbore preparation, fluid design, and wellsite execution. Design decisions made from the simulation results and improvements made with implementation of industry best practices increased the ability to get plug placement right every time from the first attempt.

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“…Em seguida, foram investigadas as conseqüências da alteração da razão entre densidades no processo de tamponamento. Abaixo, iniciou-se essa análise 10 1,00…”

Section: Influência Da Razão Entre Densidadesunclassified

Numerical Study of Oil Well Plugging Process

Feital¹,

Naccache²

2015

23rd ABCM International Congress of Mechanical Engineering

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À minha orientadora Professora Mônica Feijó Naccache pelo incentivo e cooperação para a realização deste trabalho.Ao CNPq e à PUC-Rio, pelos auxílios concedidos, sem os quais este trabalho não poderia ter sido realizado.Aos meus pais, Ricardo José Feital e Myriam Cavalieri D'Oro Feital, pelo constante apoio, estímulo, educação, carinho e atenção.Aos meus amigos da PUC-Rio.Aos professores que fizeram parte da banca examinadora.A todos os professores do Departamento pelos ensinamentos e cooperação.A todos os familiares e amigos que me ajudaram e me incentivaram. AbstractFeital, Rafael José Cavalieri; Naccache, Mônica Feijó (Advisor). Numerical study of oil well plugging process. Rio de Janeiro, 2015. 109p. MSc.The plugging process of an oil well was analyzed numerically. In this process, the denser fluid is the cement plug, which was placed above the drilling fluid in a vertical well, resulting in an unstable situation. The cement plug was modeled as non-Newtonian and the drilling fluid was considered Newtonian in some cases and non-Newtonian in other cases. The flow solution is studied using the ANSYS Fluent program. The conservation equations were solved using the Finite Volume Method, and the multiphase flow was modeled with the Volume of Fluid method.The non-Newtonian viscoplastic behavior of the cement plug was modeled with the Generalized Newtonian Fluid constitutive equation, with the Herschel-Bulkley viscosity function. The success of the operation was determined by the combination of the governing rheological and geometric parameters. The effect of the governing parameters, such as the density ratio and the viscosity ratio, were investigated for a fixed geometry and a fixed ratio between the cement plug length and diameter. Furthermore, the influence of this ratio in the process was also analyzed while others governing parameters were fixed. It was shown that the flow is highly unstable, and that the governing parameters considerably affect the operation.

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Cement Plugs: Stability and Failure by Buoyancy-Driven Mechanism

Cited by 21 publications

References 15 publications

Upper bounds on the slump length in plug cementing of near-horizontal wells

Upper bounds on the slump length in plug cementing of near-horizontal wells

Modified Approach Leads to Successful Off-Bottom Cementing Plugs in Highly Deviated Wells in the Caspian Sea

Numerical Study of Oil Well Plugging Process

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