Sand deposition inside a horizontal well - A simulation approach

Horizontal wells have been shown to be successful in improving oil recovery for marginal heavy oil reservoirs in Saskatchewan and Alberta. One commonl y encountered problem in recovery operations for these poorly consolidated reservoirs is the production of sand and fines into the horizontal wellbore , where they settle and accumulate. This paper reports the numerical modell ing of gravitational deposition of sand in a horizontal well in such heavy oil reservoirs. The numerical model described in this work examines the transport process m echanistically, based on the conservation equations for the fluid phase (he avy oil) and the solid phase (sand particles). The interaction between thes e phases is described by empirical correlations. The equations are solved n umerically to determine the concentration of sand particles and oil, and th eir respective pressure and velocity distributions inside the horizontal we ll. According to the simulation results, oil viscosity and particle size play i mportant roles in the transport process, including controlling the gravitat ional settling tendency of solid particles inside the horizontal wellbore. The results provide insight into the roles different mechanisms affect the transport of sand particles; as such, they provide guidelines for productio n operations involving horizontal wells in poorly consolidated and unconsol idated reservoirs.