Stackable straddle systems are presented as an effective method of increasing oil production rates in a highly deviated extended reach borehole, by isolating or reducing gas production from high influx zones.
In the case study presented in this paper an openhole gravel pack (OHGP) production well was experiencing a high gas/oil ratio (GOR), with production from the upper gas zone limiting oil production from the lower zones. The borehole was highly deviated with a maximum inclination of 72° and an extended reach of 5800 meters. A gas shut off intervention solution was required.
Tractor conveyance and powered mechanical stroker systems were selected to deploy the stackable straddle system, because they were the most effective and precise method. Gas/oil production data and a distributed temperature sensing (DTS) system log were used as inputs for the optimal straddle length and position.
The stackable straddle system, with a total length of 70.2 meters and isolation length of 64.7 meters, was successfully deployed and sealed off against the OHGP completion in the required position to shut off unwanted gas production. The oil production rate increased by approximately 3,000 stb/D. The GOR decreased from approximately 5,200 to 4,100 scf/bbl.