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Prediction of Sand Production in Extraction Wells Using Numerical Simulation Based on Finite Element Method

Fetrati, Majid | 2018

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 51171 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Pak, Ali
  7. Abstract:
  8. Sand production is a phenomenon of producing solid particles together with the reservoir fluid. Material degradation is a key process leading to sanding. Drilling operation, cyclic effects of shut-in and start-up, operational conditions and reservoir pressure depletion may gradually lead to sandstone degradation around perforations and boreholes. Sand production is a major issue and has an adverse impact on production cost that gas and petroleum industry have faced for decades. Corrosion of the pipelines and surface facilities, sand-oil separation cost, repeated shut-in and clean-up of the wellbore are some of the examples. On the other hand, a controlled sanding could be beneficial in increasing the production rate.It is estimated that 70 percent of the total world’s oil and gas reserves are found in poorly consolidated reservoirs. Weakly consolidated sandstone reservoirs are prone to solid production with fluid flow. Hence, the study of the material degradation and fluid drag force are essential. This thesis is about studying the sanding problem using numerical modelling with finite element method. For this purpose, Abaqus software is used for numerical modelling, and the porous medium is considered a two-phase fully saturated medium (solid and fluid). The problem modelled in 2D and 3D (axisymmetrical). Sanding model that used in this study predicts the onset of sanding and volumetric production of sand with coupling between mechanical failure and erosion behaviour of the solid due to the fluid flow. Erosion takes place if the drag force exerted on the surface particles overcome the cohesion between surface particles, which results in the release and transport of sand particles by the fluid. For simulating erosion, the sand erosion criterion proposed by various researchers implemented into the finite element code. Erosion equations are defined using specific subroutine written in Fortran and linked to Abaqus. Arbitrary Lagrangian-Eulerian (ALE) adaptive mesh technique is used in the domain near the wellbore in Abaqus. Also, the Map solution technique is used where required.The obtained results indicate the efficiency of the model used in the evaluation of sanding in sandstone reservoirs. Also, some of the principal parameters affecting sand production are studied. The effect of these parameters has well seen in numerical modelling. These parameters are permeability, in-situ stresses, reservoir rock mechanical properties, perforation orientation, and drawdown effect. Finally, the examination of different parameters affecting sand production culminated in that the criteria used in this study has the ability to simulate sanding process under different conditions. They can be used in designing sand control and management systems and determining the critical depth of sanding in oil wells
  9. Keywords:
  10. Numerical Modeling ; Finite Element Method ; Sanding Criteria ; Erosion Modeling ; Sand Production

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