Successful Foam EOR Pilot in a Mature Volatile Oil Reservoir Under Miscible Gas Injection

Abstract

A successful field trial of foams as gas injection conformance enhancer has been deployed in the Cusiana field in Colombia, South America. This work describes the Front End Loading (FEL) process done to get to the field trial, the field operation itself, and the results obtained so far. The Foam treatment was deployed in the Mirador formation of the Cusiana field, a low porosity quartzarenite with a recovery factor over 50%.The reservoir fluid is a volatile oil developed under an extensive gas reinjection process. The foam treatment was engineered to improve both the gas injection conformance at the wellbore and also the gas sweep efficiency deep into the reservoir. An extensive FEL including chemical product screening, foam stability at reservoir conditions, coreflood experiments, reservoir modelling, and a careful selection of well candidates was executed for this pilot. The treatment was done in a gas injector well in the northern part of the field, where high RF has already been obtained with high levels of gas recycling. The operation was performed using the SAG method. The foaming surfactant was pumped selectively in front of the dominant injection layer and then the well was put back on injection. The results showed a clear and sustained change in GI conformance reducing the injectivity of the treated layer by 60%. Increase in oil rate along with decreases in GOR was also observed in the nearby oil producers two months after the treatment. Results herein presented confirm the viability of foams as an EOR method for the Cusiana field and at least two other fields located in the same basin and exploited under similar conditions. Introduction The Cusiana field currently operated by Equion Energía Ltd is located in the foothills of the Eastern Mountain chain in Colombia - South America, and started production in 1994. It comprises three stacked reservoirs (Mirador, Barco and Guadalupe) and two compositional fluid systems both being volatile oils with a rich gas cap near critical conditions with pressures and temperatures over 5000 Psia and 250 F respectively (Lee et al, 1996). Initial fluids in place added up to about 1.5 bn STB of oil and over 3 tcf of gas with Mirador formation bearing about 60% of total fluids. Development strategies have included natural depletion, gas recycling, water injection and gas injection redistribution. Gas recycling and re-distribution have provided the best recoveries so far.

Enhanced Oil Recovery Techniques for Indian Reservoirs

“…To overcome these problems, foam injection is introduced in 1980. This is a promising technique to increase the gas injection conformance at the well bore and to increase the sweep efficiency in miscible and immiscible gas EOR (Ocampo et al 2013). Foam has the ability to reduce the gas mobility to overcome the permeability variations (Ashoori and Rossen 2010).…”

Low Salinity Water and Foam Flooding in Sandstone Reservoirs Bearing Heavy Oil

“…Foam is usually used to improve the sweep efficiency and mobility control of the injected fluids especially gaseous (Mast, 1972;Guo et al, 2011;Denney et al, 2013;Ocampo et al, 2013;Dugstad et al, 2011).…”

“…Foams is also used in naturally fractured reservoirs (Chevallier et al, 2018) and in multi-layered systems (Lee and Kam, 2015). A field trial using foam as a gas injection conformance enhancer has been conducted by Ocampo et al (2013) resulting in a 50% incremental oil recovery with a noticeable decrease in the gas oil ratio (GOR). Another foam field project was implemented in the Snorre field (Svorstol et al, 1996;Skauge et al, 2002).…”

Investigation of the Effect of Nanoparticle-Stabilized Foam on EOR: Nitrogen Foam and Methane Foam

“…After solving production safety problems, natural gas foam flooding can be used. However, although there are many field applications of natural gas flooding, research on the natural gas foam and methane foam is still scarce. − …”