Abstract Fluid losses during overbalanced well interventions particularly in depleted and under-pressured formations can become excessive in the presence of naturally occurring fractures, vugs, and caverns. Such features in combination with hydraulically induced fractures pose a set of issues that contribute heavily to the amount of fluid being lost into the formation. In this type of scenario it is not uncommon for the rate of fluid loss to exceed available pumping capabilities. This paper highlights the successful design and implementation of a robust pill to control excessive completion fluid losses, minimize formation damage in dual-porosity reservoirs with hydraulically induced fractures, while contributing to improve injection profile. This treatment contains a low-viscosity, solids-free, relative permeability modifier system coupled with biodegradable natural cellulose fibers for lost circulation control during workover and drilling operations. This system was applied to a cased-hole oil producer completed in the presence of natural and induced fractures (4500 psi, 15,500-ft TVD, and 270°F) in the Mirador, Barco, and Guadalupe formations in Colombia. This well was intended to be converted from a high-water cut producer into a gas injector to support field revitalization. Also, better access to the Barco and Guadalupe formations was desired to increase the injection profile. Excessive fluid losses during the workover made it impossible to carry out operations as planned. Ten pills of different conventional lost circulation materials (LCM) were implemented with no success. There was still a need to reduce losses below 10 bbl/hr to continue. Two 50-bbl pills of the proposed treatment were spotted to the target zone. Losses were immediately decreased to 9.1 bbl/hr on the first attempt, enabling continuation of the interventions with no further non-productive time (NPT). After completion, the well was successfully cleaned-out with nitrogen through coiled tubing (CT), and after two months, efficient gas injection was started as planned with the desired injection profile and no signs of further damage.