Holistic Approach to Tackle Proppant Flowback & Coal Fines Challenges through In-House Engineered Chemical Formulation

ABSTRACT This paper addresses the challenges associated with coal bed methane (CBM) well dewatering, particularly the issue of proppant flowback and production of coal fines. The primary objective is to mitigate the impairment in fracture permeability caused by fines migration and assess the suitability of a developed Proppant and Fines Agglomerating Formulation (PFAF). The devised PFAF system coats proppant surfaces thus enhancing agglomeration & preventing flowback. It was synthesized after extensive evaluation of various chemicals. Agglomeration Tests, Microscopic imaging and SEM imaging was conducted to select the best performing PFAF formulation. Optimal concentration was determined through measuring maximum proppant free production rate from proppant pack. Effect of PFAF on permeability was evaluated on fracture conductivity setup. A visualization assembly was fabricated to visualize the migration of fines in proppant pack before and after treatment with PFAF. Compatibility of PFAF with conventional fracturing fluid was evaluated through rheological tests to employ PFAF during Fracturing. Extensive laboratory studies indicate that the developed PFAF, a reaction product of an amine and ester exhibits promising results thereby reducing clean-up time and cost. The proppant treated with PFAF agglomerated and descended slowly as one piece of consolidated mass indicating reduced proppant flowback, as compared to untreated proppant which fell as individual sand grains. Microscopic study shows uniform adsorption and SEM imaging indicates non-glue like behaviour with developed formulation. The Maximum Proppant Free Production rate significantly increased post-treatment, from 350 cc/min to 900 cc/min, indicating proppant consolidation. No significant change was observed in the permeability of the treated proppant pack. Fines Migration visualization shows the retention of coal fines in the treated pack, affirming the efficacy of PFAF in mitigating coal fines. No adverse behavior was observed in compatibility study of PFAF with conventional guar based fracturing fluid. Near Zero magnitude zeta potential values were obtained with PFAF which corroborated with other test results. This paper introduces a novel Proppant and Fines Agglomerating Formulation (PFAF) to address fines-related challenges in CBM wells. PFAF demonstrates unique consolidation properties without compromising the fracture conductivity, as demonstrated by laboratory studies. The paper contributes additive information to the existing literature by presenting a practical solution for mitigating fines migration and proppant flowback in CBM wells.