Numerical modeling of the effect of Anderson's stress regimes on the volume of sand production in oil wellbores

Abstract

Sand production is a complex mechanism that reduces oil and gas production and leads to wellbore instability, tubing erosion, and even erosion of surface installations. The hydrodynamic action of the flow on the surface leads to the breakup of solid particles from the surface. This is one of the main sources of sand production. The sand production may be affected by the combination of flow rate and the stress regime around the wellbore. In this paper, sand production in a vertical wellbore is numerically studied. A 3D finite element model in various stress regimes (i.e., normal, strike-slip, and reverse based on Anderson's classification) presenting various conditions of reservoirs was used. A typical drawdown pressure was chosen to simulate the production in the wellbore. The numerical model uses a sand production criterion based on the velocity of the fluid flow, the porosity of formation, transport concentration, and sand production coefficient to determine the initiation of sand production. The sand production volume was determined for a duration of a week in all cases. The most erosion of materials in all models occurred near the junction of the wellbore and perforation. This is an expected result since based on rock mechanics, the junction of the wellbore and perforation is also the location of the most stress concentration. It was concluded that the collaboration of high-stress concentration and high-pressure drawdown caused the excessive sanding problem. The results of the paper provide insight into the effect of stress regimes and orientation of perforation on the volume of sand production.

Keywords

• sand production
• material erosion
• 3d finite element model
• stress regimes
• drawdown pressure