Analysis of the Mechanical Stability of Boreholes Drilled in Sedimentary Rocks

Garrouch, Ali A.; Ebrahim, Abdullah S.

doi:10.1081/lft-200027840

Cited by 4 publications

(4 citation statements)

References 14 publications

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“…Overburden and lateral confining pressures generate vertical and horizontal stresses, respectively, while existing reservoir fluids contribute towards pore pressures. Drilling and excavation relieve the surrounding pressure causing stress concentrations at regions close to the wellbore face, which are initially linearly elastic [5,23]. These stress concentrations may engender shear (collapse) failure at the near-wellbore region.…”

Section: Stress Analysismentioning

confidence: 99%

“…If the density and pressure of the drilling fluid are excessive, there is a tendency for loss of circulation at the near-wellbore region producing pressures that may exceed the sum of the minimum in situ compressive stress and the tensile strength of the formation rock, thereby triggering tensile failure. Tensile failure may also be instigated if the minimum effective stress becomes tensile and greater than the tensile strength of the formation rock [5,23].…”

Section: Stress Analysismentioning

confidence: 99%

“…To determine the magnitude of these stresses it is imperative to define the boundary between the elastic and plastic regions. In general, tensile failure is instigated when the effective minimum tensile stress is equal or greater than the tensile strength of the rock [23].…”

Section: Tensile Failurementioning

confidence: 99%

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Investigating Sand Production Phenomena: An Appraisal of Past and Emerging Laboratory Experiments and Analytical Models

Eshiet

Sheng

2021

Geotechnics

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This paper provides an in-depth review of research developments on a common phenomenon in oil and gas exploration: sand production. Due to its significant impact to reservoir productivity and production efficiency, sand production has been widely researched in recent years. This paper focused on the review of historical progress in experimental and analytical studies which helped to understand the nature of the sanding mechanism and identify conditions that favour the process. Collation of the experimental data and analytical solutions and formulations enabled the authors to comment on effectiveness and also limitations of the existing experimental protocols and analytical models. Sand production models were then grouped into categories based on initiation of sanding, rate and amount of sanding as well as the failure criterion incorporated in their formulation so that it will be more convenient for future researchers to identify and adopt an appropriate model for their own research. The review also confirms that there are still some aspects of sand production requiring further investigation, and maybe a hybrid approach combining experimental, analytical and numerical methods could be the best solution for future explorations.

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Section: Stress Analysismentioning

confidence: 99%

Section: Stress Analysismentioning

confidence: 99%

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Investigating Sand Production Phenomena: An Appraisal of Past and Emerging Laboratory Experiments and Analytical Models

Eshiet

Sheng

2021

Geotechnics

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“…The results indicated that with an increase in cementing strength, efforts should be made to reduce injection speed and increase injection temperature to decrease the sand production rate as much as possible. In 2004, Garrouch et al 29 proposed that excessive density or pressure of drilling fluid could lead to tensile failure and subsequently sand production. In addition to tensile and compressive failures, researchers like Nouri et al and Eshiet et al 30,31 recognized the role of shear stress failure in sand production.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on critical sand production pressure gradient at different production stages of high temperature and high pressure tight sandstone gas reservoir

Li,

Tuo

et al. 2024

Energy Storage

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Sand production is a common issue in sandstone gas reservoir development, severely impacting the productivity of sandstone gas wells. In order to thoroughly investigate the sand production characteristics of high‐temperature and high‐pressure tight sandstone gas reservoirs, this study focuses on six core samples from tight sandstone gas reservoirs(three samples with fractures), under reservoir conditions (185 MPa, 160°C), sand production experiments were conducted to thoroughly investigate the sand production patterns in sandstone reservoirs under the combined influence of different effective stresses and production pressure differentials. The results indicate: (1) under the simultaneous increase of effective pressure and production pressure differential, sand production near the wellbore (r = 0.1 m) becomes more likely in the reservoir; (2) in actual reservoirs without fractures near the wellbore (r = 0.1 m), sand production phenomena do not occur; (3) reservoirs with fractures near the wellbore (r = 0.1 m) are more prone to sand production, under an effective stress of 90 MPa, with specimens containing fractures exhibiting a 76.48% lower critical sand production pressure gradient compared to those without fractures; (4) when the pore fluid pressure is 95 MPa, the maximum gas production rate for Well X without sand production is 12.4 × 104 m3/d. The experimental results have guiding significance for the rational production of gas wells in this type of reservoir.

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