FloWatcher system reveals allocation from individual wells
Schlumberger recommended use of the FloWatcher monitoring system to
enable the wells to be monitored individually. The system consists of a venturi
nozzle and a gradiomanometer density measurement system, a retrievable venturi
gauge, and two high-precision quartz gauges that measure the temperature and
pressure drop across the venturi nozzle. The data enable early identification
of production and reservoir anomalies, such as water or gas breakthrough,
helping reduce the cost of remediation and optimize production planning and
recovery. Two-phase total flow rate and gas or water cut can also be
The FloWatcher system was installed in one of the wells, and total
production from all three wells was monitored at the gathering point. The
continuous pressure and temperature data and application of specific workflows
transformed the downhole data into fluid flow rates and allowed that well's
performance to be accurately evaluated.
Improved allocation tracking enhances recovery strategies
Results from the FloWatcher monitoring system—independently validated by multiphase flowmeter calculations—showed that one of the three subsea wells was producing at a much higher rate than initially allocated and that no water had been produced for the first 2.5 years. Because the wells were tied in together at the gathering point, the data automatically implied that the remaining two wells had produced less than initially thought.
Because the performance of the one well affected the performance of the
other wells, the operator was able to avoid the time, expense, and added risks
of testing the wells individually. The data allowed the operator and its
partner to improve their allocation workflows, better understand reservoir
performance, identify opportunities to improve the field development plan, and
manage all three wells' performance and the consequent field performance.
The success of this FloWatcher system application showed that
performance evaluations and reservoir management strategies of multiple wells
can be improved simultaneously in subsea environments, where risks are high and
expenditures are tight. Additional benefits that can be gained from using the
FloWatcher system include the reduction of capital expenditures through the
elimination of subsea test flow lines; detection of early water breakthrough;
pressure transient analysis capabilities; and real-time, simultaneous
production allocation for multiple wells.