KL Field is located at Offshore North West Java (ONWJ) and has been producing since 1986. The field consists of several reservoir zones which had been produced in commingle scheme. While considered to be more economical in current reservoir condition, commingle production scheme is not without any drawback. The most common challenge of commingle production is allocating production for each zone and locating the remaining oil reserves throughout the field. This scheme may also leave some bypassed zones, such as low resistivity reservoirs.
The study uses KL-56 shaly sand reservoir case in which several wells are produced with commingle production scheme. In the past, only one out of four exploratory wells in KL-56 reservoir was able to flow during Drill Stem Test (DST) with very low tubing pressure. The other three wells were unable to flow even though nitrogen kick off and matrix acid stimulation have been performed. Further analysis also indicates that KL-56 reservoir has low resistivity and low permeability value. The integration of available test data and analysis above confirms the KL-56 reservoir has not been produced optimally. Infill wells were then generated to recover KL-56 reserve only. Hydraulic fracturing was selected to enhance KL-56 productivity.
In 2012, three development wells were drilled and produced at 2100 BOPD with 0% water cut. The drilling result also confirms that no reservoir pressure depletion occurred. It is also suggested that KL-56 reservoir has not contribute yet to overall production. As a bypassed zone, KL-56 leaves significant hydrocarbon reserves. For future strategy, new development wells are planned to be completed as horizontal wells with multistage fracturing to increase the productivity.
The success of KL-56 re-development leads to a new approach in low resistivity reservoir management at ONWJ: re-evaluation of bypassed zones.
