Predictive Model and Verification for Sand Particulates Migration in Gravel Packs

Abstract

A phenomenolo$jical model is presented to optimize the performance and to minimize the costs of gravel-packs, which are subjected to severe flow and pressure conditions. The theoretical basis for the development of the model equations is discussed and the equations are derived to represent the mechanisms involved in gravel-pack damage. This model is an averaged representation of the experimentally observed step-like motion of particulate, which is characteristic for particulate transport in gravelpack. An implicit finite difference solution of the gravelpack damage model is utilized.The identification of the model parameters is emphasized. The influence of error in the determination of parameters is estimated by performing a sensivity analysis. Of the three parameters, namely the amount of mobile particulate, the particle deposition rate constant, and particle mobilization rate constant, the last one is found to be less important because particle mobilization is sensitiva to reduced transport capacity of the clogged gravel-pack The model has been verified by data from a set of 35 experiments conducted via large scale non-Darcy flow tests with optically transparent filtration cell. The predictions of the model are found in reasonable agreement with the test results with respect to the particulate migration distance and the amount of mobile particulate. rI

A Study of Fluid-Flow Mechanism for Cold Production with Sand and Single-Well Fine Numerical Simulation in Heavy-Oil Reservoirs

“…The speeds of movable sands and oil phase are equal in the pore of reservoir [5] . Movable sands' effect on fluid flow is considered.…”

“…So, deposit velocity equation on the pore surfaces is given by [5] [8] When sand particulates are moved in the pore of formation, if single sand particulate whose radius is bigger than pore throat radius is captured by plugging at pore throats and several sand particulates whose radius is smaller than pore throat radius are captured by bridging at pore throats, the rate equation for the entrapment of external particles at pore throats in each fluid phase is then given by In the equation, p k is a rate constant for pore throat blocking, 1 m . But, if flow velocity of fluid phase exceeds threshold flow velocity sc V , parts of deposited sand particulates will be dragged by fluid.…”