Experimental approach for assessing filter-cake removability derived from reservoir drill-in fluids

Abstract

AbstractPredicting formation damage in cased-hole and open-hole completion wells is of high importance. This is especially relevant when the damage is caused by reservoir drill-in fluids hence being well-bore induced. Cake filter removal has proven to be a good approach to estimate induced damage and to evaluate drill-in fluids’ performance. We present an experimental methodology to evaluate filter cake removal, which could be achieved during the well's initial production. An improved experimental setup, to the ones presented in literature, has been developed to enhance data quality. A twofold approach was used for setup design, and first, it can be integrated with devices used to evaluate the static/dynamic filter-cake. Second, it can be used to simulate more realistic cases (field related) by adjusting the experiment parameters. Hence, to replicate the expected drawdown pressure as well as the corresponding flow rate of the studied reservoir. Three key indicators directly related to filter-cake removal were used as evaluators in this work. Lift-off pressure, internal and external filter cakes removal efficiency. Three reservoir fluid systems were studied, two polymer-based and one potassium carbonate. Results show that pressure required to initiate the collapsing process of the filter cake is not significant. Polymer-based drilling fluids showed better performance in terms of external and internal filter cake cleaning efficiency comparing to potassium carbonate. Moreover, we observed that filtrate volume has no clear relation with the degree of residual damage.