Triaxial Creep Tests in Salt Applied in Drilling Through Thick Salt Layers in Campos Basin-Brazil

Falcao, Jose Luiz; Coelho, L.F.M.

doi:10.2118/92629-ms

Cited by 9 publications

(7 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…1 in this analysis, salt creep parameters are required as inputs. Maia et al (2005) and Poiate et al (2006) performed triaxial creep tests on halite, carnallite, and tachyhydrite specimens cored from actual formations. The samples used were 176 mm long and 88 mm in diameter.…”

Section: Physics Of Salt Creep and Model Validationmentioning

confidence: 99%

Cement Sheath Integrity in Fast Creeping Salts: Effect of Well Operations

et al. 2013

View full text Add to dashboard Cite

A number of reservoirs around the globe are in deep environments, and often it is necessary to drill and cement through salt sections to reach them, such as in offshore Brazil. These reservoirs are mainly in deep water and are commonly referred to as pre-salt zones. It can be very challenging to drill and cement the salt section. The salt zones could be a few hundred meters thick, creep at high rates, and when in contact with drilling fluid and cement slurry, their chemical properties can change. The effect of salt movement or creep is addressed in this work.Salt formations pose a unique challenge to the structural integrity of the wellbore by applying a time varying load on the cement sheath and casing. This load is caused by the existence of deviatoric stress and temperature variations. Deviatoric stress is the difference between formation in-situ stress and the wellbore fluid's hydrostatic stress. When a salt formation creeps during a well operation, it does so to achieve a hydrostatic state such that the deviatoric stress is zero.The present work is a study of cement sheath integrity under downhole thermo-mechanical loading conditions using finite element analysis (FEA). The effect of salt creep on the stresses experienced by the cement sheath at various stages in the life of the well, including drilling, cementing, shut-in, completion, and production, are simulated. A material model for salt creep is validated against experimental data reported in the literature. Multiple cement systems are compared for their effectiveness in providing zonal isolation for the life of the well. The effect of structural and thermal loads due to salt creep on cement are quantified through stresses in cement.The method discussed in this paper should help the industry select cement formulations that can withstand stresses caused by salt movement during the life of the well. Method and case studies pertaining to offshore Brazil are presented and discussed in this paper.

show abstract

Section: Physics Of Salt Creep and Model Validationmentioning

confidence: 99%

Cement Sheath Integrity in Fast Creeping Salts: Effect of Well Operations

et al. 2013

View full text Add to dashboard Cite

show abstract

“…The relationships also capture the effect of temperature and deviatoric stress on creep rate. It is possible to determine the material constants along with their temperature and deviatoric stress dependence by performing downhole creep rate measurements using calipers (Dusseault et al 2004) or by performing triaxial creep tests on extracted salt cores (Maia et al 2005).…”

Section: Introductionmentioning

confidence: 99%

Design Procedure for Cementing Intercalated Salt Zones

Jandhyala

Ravi

Anjos

2015

Day 1 Tue, October 27, 2015

View full text Add to dashboard Cite

Wells often require being drilled through and cemented across salt formations. In many parts of the world, salt sections consist of multiple salt types. These include Halite, Carnallite and Tachyhydrite. The last two salt types could move one hundred times faster than Halite and are chemically reactive. Typically, Carnallite and Tachyhydrite occur as streaks inserted between Halite. In these cases, cement sheath should withstand salt creep loading. Creep load is primarily compressive in cases of single salt types. For intercalated salts, varying creep rates can result in tensile loads, particularly at salt-salt junctions. Presalt exploration in offshore Brazil is an apt example displaying this behavior. In such a scenario, the cement sheath along a longitudinal well section should be analyzed for both tensile and compressive responses. It is well known that tensile strength of conventional cement systems is low, hence there is the need for detailed analysis and action to prevent damage to cement sheath.This work demonstrates cement design procedures by evaluating cement sheath mechanical integrity in intercalated salts. A typical presalt Brazilian well with different lengths of Tachyhydrite, Halite, and Anhydrite sections is used as an example in this work. A creep model for these salts is validated with data from triaxial creep testing. Responses of two cement systems, which are cured and tested, are compared. The analysis accounts for classical well loads during drilling and production etc., along with salt creep loading.This analysis shows that intercalated salts subject cement sheath to a series of tensile and compressive loads whose magnitude depends on the size and relative position of different salts. The salt-salt interface effects dominated the general tenet of increasing creep rate with increasing depth.This kind of detailed design procedure representing intercalated salt zones is the first of its kind known to the authors. Results from this analysis help fortify the importance of considering salt layering patterns during cement design for long term mechanical integrity. The design procedure discussed and presented in this study should help the industry design cement systems to withstand loads across single and intercalated salt zones and maintain well integrity.

show abstract

“…No caso dos evaporitos, a deformação pode ainda apresentar dependência com a espessura da camada de sal, composição mineralógica, teor de água e presença de impurezas. (33,34).…”

Section: Fluência De Evaporitosunclassified

“…Este ponto é representando pela interseção das duas retas ajustadas ao gráfico em escala logarítmica, para os pares log( ) × log(σ ef ). O gráfico da figura 2.16 apresenta os resultados obtidos em um ensaio de laboratório para a determinação dos parâmetros utilizados no modelo de duplo mecanismo (33). software comercial ABAQUS (40).…”

Section: Modelo Constitutivounclassified

See 1 more Smart Citation

Modelagem Termo-Mecânica Do Crescimento De Pressão Em Anulares Confinados, Frente a Formações Salinas

ALMEIDA¹

View full text Add to dashboard Cite

Almeida, Luiz Felippe Medeiros de; Castro, Jaime Tupiassú Pinho de (Advisor); Júnior, Eurípedes do Amaral Vargas (Co-Advisor). Thermomechanical modeling of annular pressure build up in salt formations. Rio de Janeiro, 2016. 90p. MSc. Dissertation -Departamento de Engenharia Mecânica, Pontifícia Universidade Católica do Rio de Janeiro.This dissertation presents a thermo-mechanical numerical modeling to investigate the influence of the presence of salt rock on annular pressure build-up (APB). The APB phenomenon is a result of thermal expansion of confined drilling fluid in the well annulus, induced by heat generated by the production of hydrocarbons at temperatures above the remainder of the well. The evaporite formations have a viscoelastic mechanical behavior, with continuous deformation at constant stress, known as creep. This salt behavior is not currently considered by simulators used by the oil industry for the design of wells, with respect to this pressure load from APB. The objective is achieved by developing a methodology for calculating the APB effect for wells with saline formations, using a numerical model built in ABAQUS software, using the finite element method. Several simulations were performed with different configurations of lithology, temperature and drilling fluids, to analyze the influence of the viscoelastic behavior of the salt rock on pressure growth in confined annuli. After analyzing the results, it was concluded that the rock salt may act as a relief for the pressure generated by thermal expansion of the confined drilling fluid in the well annulus. The stresses generated by the APB lead to creep strains that increase the well diameter and consequently the annular volume, accommodating part of the generated pressure increase.

show abstract

Triaxial Creep Tests in Salt Applied in Drilling Through Thick Salt Layers in Campos Basin-Brazil

Cited by 9 publications

References 1 publication

Cement Sheath Integrity in Fast Creeping Salts: Effect of Well Operations

Cement Sheath Integrity in Fast Creeping Salts: Effect of Well Operations

Design Procedure for Cementing Intercalated Salt Zones

Modelagem Termo-Mecânica Do Crescimento De Pressão Em Anulares Confinados, Frente a Formações Salinas

Contact Info

Product

Resources

About