Formation Damage vs. Solid Particles Deposition Profile During Laboratory-Simulated Produced-Water Reinjection

Abstract

Summary The importance of produced water reinjection (PWRI) is unquestionable. It is in many cases the cheapest and most environmentally friendly solution for wastewater disposal. It is also a feasible method for enhanced oil recovery (EOR) as a waterflooding mechanism. PWRI, however, suffers from a major limitation, which is the current inability in accurately predicting the lifespan and performance of its injection wells. This is because of the multitude of parameters that affect it. Current models1,2 that incorporate the thermal effects3 of PWRI leading to fracture growth exist. However, the leakoff pattern of this injection differs from that of clean water (seawater) injection because of the damage caused by the produced water to the formation, especially to the fracture faces. Thus, static filtration experiments with refined post-mortem analysis have been conducted to obtain quantitative deposition profiles along the core. This allows for the testing and verification of existing models.4–8 The post-mortem analysis introduced in this paper will be used for future dynamic filtration experiments as well as experiments specifically devised to simulate the fracture tip area. A unified model that will accurately reproduce the permeability decline and deposition profile for all three sets of experiments will follow, thus advancing the predictability of injectivity decline associated with PWRI. The purpose of this paper is to provide a detailed description of the post-mortem analysis, while rigorous testing of the existing heuristic models (for instance, Wennberg and Sharma6 and Bedrikovedski et al.7) will be published in the near future.9