Bhagyam field is located in the prolific Northern Barmer Basin in Rajasthan, India. It has nearly 110 producers and some of these wells have limited pressure support and are geologically distinct from the rest of the field. These wells are flowed intermittently according to a pre-defined cycle based on flowing bottom-hole pressures to optimise their production. Various stimulations have been attempted to increase near wellbore productivity. However, these have largely been unsuccessful. A further restriction is posed by the completion of these wells on Progressive Cavity Pumps (PCPs) as the artificial lift method which inhibits the use of acids and aromatic compounds.
This paper illustrates the successful trial of surfactant stimulation in increasing the productivity of these wells. Surfactants were considered as an alternative technique for stimulation as they pose no harm to the PCP elastomers. In addition to this, they help alter the wettability in the mixed wet to oil wet reservoir of Bhagyam field. The stimulations were designed to get the maximum penetration and were bull-headed from surface. This paper also discusses the unsuccessful stimulations carried out prior to field trial of surfactant stimulations and the studies done in the field to understand the damage mechanism behind low productivity/productivity decline. More than 10 wells (both low PI wells and intermittently flowing wells) have been successfully stimulated with surfactants till date in the field and have helped substantially in sustaining the overall field production.