Overcoming a Difficult Salt Drilling Environment in the Gulf of Mexico: A Case Study

Chatar, Crispin; Mohan, Sushil; Imler, Mark D.

doi:10.2118/128192-ms

Cited by 16 publications

(5 citation statements)

References 4 publications

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“…Even though numerous efforts have been made to investigate geomechanical properties of salt rock and the associated challenges on drilling and wellbore stability (Chatar and Imler, 2010;Hansen, 2011;Lao et al, 2012;Mathur et al, 2010;Mackay et al 2008), few literature is available to demonstrate a comprehensive model to predict the stress load on casing in salt formations under various conditions during the long-term production period in a rigorous way, by including the impact of temperature disturbance and considering salt formation, cement and wellbore casing as an integrated system. Khalaf and Cairo (1985) used a model derived from Lame's elastic solution for a thick cylinder loaded with uniform internal and external pressure to evaluate the strength of concentric casings packed with cement.…”

Section: Fig1mentioning

confidence: 99%

3D Geomechanical Modeling of Salt-Creep Behavior on Wellbore Casing for Presalt Reservoirs

Wang

Samuel

2016

SPE Drilling &Amp; Completion

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Exploration drilling is venturing out into deeper regions of water. While exploring these deeper water depths, large hydrocarbon deposits have been found below salt formations. These reservoirs are located in formations called "pre-salts," which are located below the salt formations. Pre-salt reservoirs have been found in offshore Brazil, the Gulf of Mexico, West Africa, and the North Sea. Completions in salt formations can be difficult owing to the creep behavior that the salt formations exhibit. Creep behavior results from the instability of the salt formation, which causes a slow flow and permanent deformations. Creep deformation occurs over time and is initiated once the salt formation has been penetrated. Completion of the wellbore does not stop formation creep. The constant creep of the salt formation causes excess stress on the wellbore casing, which may eventually cause the casing to collapse. In this study, a 3D geomechanical model is developed, using data such as wellbore pressure and temperature, formation stress and temperature, rock, cement, and casing properties, to predict the effects of salt creep behavior on stress loading in the wellbore casing, which helps to assess the life expectancy of wells in pre-salt reservoirs. The simulation results of this model can provide quantitative results of casing stress and deformation as a function of time under various temperature, in-situ stress and operation conditions, that can be used as useful information for subsequent wellbore casing design and wellbore integrity analysis. In addition, possible methods that can mitigate the severity of salt mobility and reduce the risks of casing collapse are discussed.

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Section: Fig1mentioning

confidence: 99%

3D Geomechanical Modeling of Salt-Creep Behavior on Wellbore Casing for Presalt Reservoirs

Wang

Samuel

2016

SPE Drilling &Amp; Completion

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“…This strategy can be assisted by cooling the wellbore fluid to retard creep, which is highly temperature dependent (Dusseault et al 2004). Alternatively, reaming, washing and jarring may be needed to keep the wellbore open (Chatar et al 2010). The drilling-fluid density chosen to counter wellbore closure is critically dependent on anticipated conditions in the salt body.…”

Section: W E L L B O R E S Ta B I L I T Y I N S a Lt F O R M At I O N Smentioning

confidence: 99%

Closure of open wellbores in creeping salt sheets

Weijermars

Jackson

Harmelen

2013

Geophysical Journal International

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Safe exploration and production of pre-salt (or subsalt) hydrocarbons require that drilling operations be optimized. We introduce analytical models of wellbore closure, accounting for variations in both the wellbore net pressure and far-field flow rate of an autochthonous or allochthonous salt sheet penetrated by the wellbore. We demonstrate how closure rates of such a wellbore evolve for increasingly stronger Rankine flow. For high viscosity salt (∼10 18 Pa s) the wellbore closes by a pure sink flow without any Rankine shift from its vertical trajectory path. For low viscosity salt (∼10 16 Pa s) Rankine flow dominates. Wellbore closure in salt sheets may vary within the same wellbore due to differential tectonic creep rates at different depths. Mitigation of wellbore closure by, for example, reaming, jarring, brine solution and thermal control, is most effective if spatial variation in closure rates is understood and quantified. Evaluation of wellbore closure rates due to salt creep should be customarily included in wellbore stability analyses before drilling and during well monitoring.

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“…Deep-water drilling risers will have a significant impact on drillstring vibration [1,2], which is a crucial factor affecting drilling efficiency. The high levels of shock and vibration experienced during deep water drilling in Brazil [3][4][5] and Mexico [6][7][8] have severely affected the rate of penetration (ROP). Moreover, the presence of complex-coupled vibrations such as stick-slip and whirling phenomena poses great challenges to deep water drilling operations.…”

Section: Introductionmentioning

confidence: 99%

Research on the Influence of Deep-Water Drilling Risers on Drillstring Motion Trajectory and Vibration Characteristics

Hai,

He,

Xue

2024

Machines

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The swing of the riser in deep-water drilling can significantly impact the drill string. In this study, we establish a riser model that considers the combined disturbance of periodic dynamic wind and wave loads. By coupling it with the drill string model, we develop a dynamic model for deep-water drilling systems. Through analyzing multiple sets of different drilling parameters, we examine displacements and impact forces at various positions along the drill string system. Specifically, our focus lies on velocity, acceleration, and rotational speed information of BHA. We investigate how WOB and rotational speed influence motion trajectory and vibration characteristics of the drill string within the dynamic model of deep-water drilling systems. Simulation results reveal slight differences in whirling trajectories between inside the riser and below mud line for the drill string. Rotational speed has a greater impact on the drill string compared to WOB; higher rotational speeds lead to increased collision forces between the drill string system and both riser and wellbore. Our findings identify specific combinations of WOB and rotational speed parameters that can stabilize drilling operations within dynamic models for deep-water drilling systems. These research results provide valuable insights for adjusting WOB and rotational speed parameters in deep-water drilling.

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Overcoming a Difficult Salt Drilling Environment in the Gulf of Mexico: A Case Study

Cited by 16 publications

References 4 publications

3D Geomechanical Modeling of Salt-Creep Behavior on Wellbore Casing for Presalt Reservoirs

3D Geomechanical Modeling of Salt-Creep Behavior on Wellbore Casing for Presalt Reservoirs

Closure of open wellbores in creeping salt sheets

Research on the Influence of Deep-Water Drilling Risers on Drillstring Motion Trajectory and Vibration Characteristics

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