Asphaltene Characterization and Mitigation in South Kuwait's Marrat Reservoir

Abstract

Summary This study addresses two aspects for mitigating production problems in south Kuwait's Marrat wells in the Magwa area of the Greater Burgan field. Characterizing single-phase oil samples collected from four wells. Finding a pragmatic and cost-effective solution to tubular-deposition problems. We took two approaches for laboratory investigation. In the first approach, a gravimetric technique was used to establish asphaltene onset pressures (pao) at various temperatures, leading to the generation of the asphaltene flocculation envelope (AFE). The second approach entailed the use of acoustic resonance technique (ART) for rapid determination of both pao and bubblepoint pressure (pb) in one experimental run en route to the development of a solvent— deasphalted oil. Fluid characterization also included thermodynamic modeling. Asphaltene is treated here as a solid phase in equilibrium with the reservoir fluid, which is modeled by an equation-of-state (EOS) model. We reproduced the observed features of various isotherms quite well, lending credence to the modeling approach. Following fluid characterization, we sought a cost-effective and environmentally friendly solvent. The search for a solvent led us to the development of deasphalted oil. We designed and conducted a series of experiments to deasphalt the Marrat oil and examine its potency as a solvent. Results showed that the use of 20% deasphalted oil with 1% dispersant, both by volume, can ensure solubility of asphaltenes in the entire flow string during production. EOS modeling on deasphalted oil was also done for computing onset pressures at various temperatures with good success. Field trial results are also included to show its partial success in well-bore remediation.