PORE NETWORK MODELLING OF FORMATION DAMAGE DUE TO SUSPENDED PARTICLES

Abstract

Formation damage caused by suspended particles takes place in various stages of drilling and production operations. The particles in drilling fluid, completion fluid, workover fluid, or injected water can clog the formation and cause severe reductions in productivity or injectivity. Related research has been conducted for years and the most widely used models are empirical, based on specific core flooding data. These models are easy to use; however, when they are applied to formations with different characteristics, the predictions are often rather poor.

This work investigates a promising way to model formation damage at the pore level. Even though reservoir rocks have very different characteristics, they are all combinations of pore necks and pore bodies. In the proposed model, pore necks are represented by tubes and pore bodies are represented by globes to form a 2D network where particle deposition takes place. The pore size distribution is measured by porosimetry and assigned to the network. By adjusting the parameters of the pore necks and pore bodies, this pore network model can represent real porous media quite well. Surface deposition was considered to be the main mechanism of formation damage for small particles. The model was validated with lab test data and reasonable results were obtained. Compared with the empirical model, the pore network model could be applied to a much wider range of reservoirs.