Cements for Long Term Isolation - Design Optimization by Computer Modelling and Prediction

Lullo, Gino Di; Phil, Rae

doi:10.2523/62745-ms

Cited by 12 publications

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“…Over the past ten years, several papers were concerned with the long term mechanical durability of the cement sheath. However, until now there are no relevant physical and mechanical inputs that allow to evaluate the development of stress and strain states in the cement at very early age of hydration in oil or gas wells [1][2][3][4]. The monitoring of mechanical properties measurements of the cement paste at very early age under downhole conditions is not trivial due to the lack of instrumentation that can help curing and maintaining the cement paste under downhole conditions while testing for mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Evolution of the Elastic Properties of an Oilwell Cement Paste at Very Early Age under Downhole Conditions: Characterization and Modelling

Bourissai

Meftah

Brusselle-Dupend

et al. 2013

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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Re´sume´-É volution des proprie´te´s e´lastiques d'une paˆte de ciment pe´trolier au tre`s jeune aˆge dans des conditions HP/HT : caracte´risation expe´rimentale et mode´lisation -Une mode´lisation multie´chelle, couple´e avec un mode`le d'hydratation, est propose´e pour pre´dire l'e´volution des proprie´te´s e´lastiques d'une paˆte de ciment pe´trolier au tre`s jeune aˆge (jusqu'a`un jour). Des re´sultats expe´rimentaux montrent que la pression applique´e (1-200 bar) pendant la prise a peu d'effet sur la cine´tique d'hydratation contrairement a`la tempe´rature (20-60°C). Le mode`le d'hydratation retenu a e´te´valide´par des mesures calorime´triques. Les re´sultats de porosited e´duits de ce mode`le d'hydratation sont d'ailleurs cohe´rents avec des mesures de la porositeć onnecte´e effectue´es a`diffe´rents degre´s d'hydratation. La mode´lisation multi-e´chelle par homoge´ne´isation prend en compte l'e´volution des fractions volumiques des constituants de la paˆte de ciment au cours de l'hydratation. Le de´veloppement des proprie´te´s e´lastiques du ciment pe´trolier au tre`s jeune aˆge obtenues avec ce mode`le est en bon accord avec les mesures obtenues par la propagation d'ultrasons.Abstract -Evolution of the Elastic Properties of an Oilwell Cement Paste at Very Early Age under Downhole Conditions: Characterization and Modelling -A multi-scale homogenization approach coupled with a hydration model is adopted to predict the bulk and shear moduli evolution of an oilwell cement paste at a very early age (up to one day). Calorimetric experiments were performed to be compared with the results of the kinetics model and also to study the pressure and temperature effects on the hydration kinetics. The homogenization model results are in agreement with the elastic moduli measurements obtained from propagation of ultrasonic waves.

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Section: Introductionmentioning

confidence: 99%

Evolution of the Elastic Properties of an Oilwell Cement Paste at Very Early Age under Downhole Conditions: Characterization and Modelling

Bourissai

Meftah

Brusselle-Dupend

et al. 2013

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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Modeling the Failure of Cement Sheath in Anisotropic Stress Field

Bui

Tutuncu

2013

All Days

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The primary objective of a cementing job is to create a stable mechanical link between the casing and formation. This link provides a strong support for the casing and isolates different zones to prevent any contamination to aquifers during the lifecycle of the well. The damage of the cement sheath may result in contamination of drinking water resource and negative environmental impact. Hence, the loss isolation of the cement has received much attention from researchers and the public.The possibility of losing the isolation of the cement sheath during the lifecycle of the well is summarized and the potential risk in contaminating underground water formations is discussed in this paper. A mathematical model for predicting the failure of the cement sheath in an anisotropic stress field is presented. The model combines the effect of temperature, the variation of stress around the wellbore, internal pressure, and the integrity of the casing, cement, and rock formation. The objective of the model is to obtain the maximum internal pressure that we can apply on the casing without causing cement sheath failure. A numerical simulator was developed to calculate this maximum pressure for any inclination and azimuth angle. Computational results show that cement sheath failure depends strongly on the in-situ stress field of the surrounding formation. With stronger uniform formation support, the casing and cement can withstand larger internal stress. The failure of the cement sheath is more severe in a highly anisotropic stress field than in an isotropic field. Hence, the assumption of uniform formation stress around the wellbore may cause significant error in predicting failure of the cement sheath.The results of this study provide petroleum engineers a tool to determine the maximum internal pressure during drilling, production and stimulation to avoid losing cement isolation. It is recommended to use this model to check the integrity of the wellbore during any operations during the lifecycle of the well. IntroductionCurrently, there is a public concern regarding contamination of drinking water resources by the oil and gas operations. This contamination was originally claimed to be the result of well stimulation operations such as hydraulic fracturing. However, recent researches showed that the loss of the cement sheath isolation also is the main contributor to this contamination. Cement failure may destroy the integrity of the wellbore and create the channel for fluid mitigation between different formations. This can lead to lost production due to excessive water production, create the hazard to rig and production operations, and also contaminate shallow aquifers. The loss of isolation of surface aquifers is the result of many factors. In general, poor cementing job and the damaging effect of drilling, stimulation, and production activities are the main reasons for the failure of cement bond. With the increasing in number of wells in unconventional reservoirs, more stimulation operations are needed to successfully develop th...

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Engineered Fit-For-Purpose Cement System to Withstand Life-Of-The-Well Pressure and Temperature Cycling

Al-Yami

Wagle

Abdurrahman

et al. 2017

Day 3 Wed, November 15, 2017

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Due to pressure and temperature changes during the life of the well (from drilling to production); globally many Casing-Casing Annular (CCA) leaks are observed in the annuli between surface and intermediate casings. A new approach to well cementing had to be developed, and advanced cement technologies considered, taking into account both short and long term design parameters. To assess the effect of pressure and temperature cycling on the long-term well integrity, finite element modeling of sections of interest was performed to analyze the stresses applied on the cement sheath throughout the life of the well. Such modeling requires detailed knowledge of the pressure and temperature cycles, as well as the mechanical properties of the formations, casings and cement. The output is a failure analysis of the cement sheath in terms of compression, tension and micro annulus development. Once the failure mechanisms are well understood, further sensitivity analyses permit to select the most adequate cement system for the application, based on target windows of compressive and tensile strengths, Young's modulus, Poisson's Ratio, and expansion capacity. The paper will discuss a case study where a fit-for-purpose durable cement system was designed to meet the required mechanical properties as suggested by the stress modeling performed on a candidate well. It was placed as a Tail slurry on the 9 5/8" Tieback casing to provide 1000 ft. of long-term hydraulic isolation in the cased annulus should the liner top packer fail to seal the high-pressure water formation below. A post-job analysis using job data and cement evaluation logs showed that placement was executed as per design and that the durable cement system provided excellent bonding and annular coverage. The well was later drilled to total depth, completed, fractured and delivered to production without CCA pressure at the wellhead. The new approach consists of performing finite elements stress modeling during the well planning phase to custom design cement systems that will withstand the anticipated loads.

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Cements for Long Term Isolation - Design Optimization by Computer Modelling and Prediction

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Cited by 12 publications

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Evolution of the Elastic Properties of an Oilwell Cement Paste at Very Early Age under Downhole Conditions: Characterization and Modelling

Evolution of the Elastic Properties of an Oilwell Cement Paste at Very Early Age under Downhole Conditions: Characterization and Modelling

Modeling the Failure of Cement Sheath in Anisotropic Stress Field

Engineered Fit-For-Purpose Cement System to Withstand Life-Of-The-Well Pressure and Temperature Cycling

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