Low Injection Squeeze to Reduce Gas Oil Ratio Gain Significant Crude Production using Epoxy Resin Technology

摘要

NI-5 is a first-stage development well in the NI field, Rajasthan. After bringing it on production, a high gas/oil ratio (GOR) of approximately 2,500 scf/STB was observed. In comparison, offset wells in the same field commonly had GORs of 250 to 300 scf/STB. The well was taken off production and shut-in as a result. This paper presents a remedial cementing operation including the development of a synthetic resin-based sealant to bring this well back onto production. Identification of the ideal treatment zone used open hole logging techniques combined with a cement bond log (CBL) to locate the gas/oil contact (GOC) and determine the condition of the cement sheath. These results indicated only minimal injection would be achievable, and to seal the suspected leak, a material would need to be placed to establish isolation between the GOC and the producing perforation. The chances of success with a conventional cementing solution were low. In addition, potential contamination could compromise strength development. An epoxy resin system was selected for this gas shutoff treatment because of its high-penetration ability, strength once set, and ability to resist contamination. Strategic placement of a low-volume sealant focused on accessing the zone of interest through perforation, cleanout, zone preparation to receive the treatment, multistage squeeze techniques, and treatment removal from the casing by drilling. Conventional cement testing equipment was used to customize the resin formulation to the downhole conditions. After placement and solidification of the resin, a reliable barrier was formed, and the resin remaining in the casing was able to be successfully drilled. The well was brought back online and is currently producing approximately 1,000 BOPD with GOR on par with other wells in the same field. The epoxy resin technology has unique properties, which makes it best suited for gas shutoff especially in tight geometries such as in this case of micro-annulus channel in cement sheath. The resin system is solids-free (Newtonian fluid in a liquid state) and can provide a high-pressure seal. The system also withstands contamination (overcomes inefficient mud displacement). In addition, this drillable system develops compressive strength ranging from 5,000 to 15,000 psi.