Dynamic control balances the flow
LUKOIL-Nizhnevolzhskneft and Schlumberger devised a multidisciplinary
approach to improve recovery in the field. Two new wells and two sidetracks
were designed with intelligent multizone completion technology, including
pressure and temperature gauges for each zone. The sensor data eliminate the
need for production logging and extended surface well testing of individual
zones, and the related time and risk associated with those functions. Each of
the zones in the new completions also included TRFC-HD dual-line, multiposition
FCVs, which (unlike ICDs) can be remotely and rapidly adjusted to suit variable
and inconsistent downhole conditions.
To manage data and respond more rapidly to reservoir dynamics, the
operator chose the WellWatcher Advisor software, which combines the pressure
and temperature data from gauges with the flow-control valve position
information to assess flow contribution and productivity indices by lateral in
real time. This allows the operator to optimize the settings on the
flow-control valves for maximum production and reservoir sweep efficiency. The
software provides almost-real-time pressure transient or nodal analysis rather
than weeks of manual engineering time, enabling unprecedented awareness and
control of reservoir variations.
Intelligent wells lead field production
The first intelligent completion in the project became one of the best
producers in the Korchagin field.
Production in the first multilateral well, which consisted of the
motherbore and one side track connected by a junction, was achieved with much
lower drawdowns than for a single-lateral well. GOR and water cut improved when
compared to offset wells where gas and water breakthrough had been observed. In
the second multilateral well, also a motherbore with one side track connected
by a junction, the intelligent completion redistributed the drawdown between
and along the laterals. This resulted in a 75% reduction in GOR while the oil
production rate more than tripled compared with previous wells without side
tracks.
The fourth intelligent completion was installed in one of the oldest
wells in the Korchagin field. A new horizontal wellbore was drilled as a side
track and split into three intervals isolated by packers after the motherbore
was abandoned. FCVs and pressure and temperature gauges were installed in each
zone to control inflow. The first zone intersected a fracture so GOR and water
cut were high— but completely controlled by the FCV. In the second
interval, a highly productive oil zone, overall production was good. The
operator determined that without the use of the intelligent completion
strategy, the well would have been choked back at surface because of
uncontrolled gas breakthrough from the fracture resulting in a reduction in
well productivity.
Overall, in 2 years the intelligent completions boosted recovery for the
Tithonian reservoir by 41% and increased oil production by 3.5 MMbbl [0.56
MMm3]. Of the 23 ERD wells in the Korchagin field, the four
intelligent wells account for 30% of the total produced oil. Expanding on the
success of these initial intelligent multilateral completions,
LUKOIL-Nizhnevolzhskneft has adopted the approach for development of new
Caspian fields.
