Using Screen Models to Evaluate the Injection Characteristics of Particle Gels for Water Control

摘要

A trend in oilfield water management is to use preformed particle gel (PPG), a kind of superabsorbent polymer, to control water production and enhance oil recovery for mature oilfields. Therefore, it is of major importance to examine PPG injection characteristics and thus provide a practical guide to screen and determine the best PPG for a specific reservoir. In this study, a series of experiments were performed using screen models to study the effect of the particle gel swelling ratio (depending on brine concentration), injection rate, and the open hole size of the screen on the gel injection pressure and injectivity. Experimental results illustrate that the PPGs prepared in high concentration brine present higher gel strength than those prepared in low concentration brine. The gel strength is a more controlling factor than the particle size of the swollen PPG for the particle injectivity. At higher injection rates, the injection pressure does not increase significantly with injection rates, which is very consistent with the real-time injection pressure and injection rate change observed during practical gel treatments in oilfields. These gel particle injection behaviors are completely different from the behavior of conventional hard particles in that they are elastic and deformable during extrusion.