To optimize production and ultimate recovery while controlling capital, drilling, and operating costs, Saudi Aramco uses extreme reservoir contact (ERC) wells with multiple laterals and producing zones in heterogeneous carbonate reservoirs, thereby limiting the number of wellheads and surface infrastructure.
Effective management of production from individual lateral compartments with different pressures, water cuts, and flow regimes was challenging because of the difficulty of placing control technology into laterals. If water or gas broke through in one of the laterals, a production logging intervention or complex surface well testing was required to identify which lateral was affected. In addition, drawdown from each zone in each lateral could not be actively monitored or controlled to optimize well cleanup for maximum productivity. Saudi Aramco wanted to address these challenges in an ERC well via downhole sandface monitoring and control within each of the three laterals.
The Manara system was developed by SLB in close collaboration with Saudi Aramco. It incorporates pressure, temperature, flow rate, and water cut sensors packaged in one compact station with an electric interval control valve (flow control valve). Use of AC power and field-proven, ESP-noise-immune bidirectional telemetry enables wireless transmission of power and data across junctions via inductive couplers. As a result, simultaneous monitoring and control of multiple zones across junctions is available.
A total of six stations were distributed across the trilateral well, two in each lateral branch, powered by four inductive couplers. The Manara system's measurement and control capabilities enabled production engineers to react to changing reservoir conditions, balance drawdown across the full 6 km of reservoir contact, and optimize well cleanup zone by zone.
During cleanup, high drawdown caused free gas to form, but it was quickly detected and adjustments made in real time to control the situation. As a result, the lateral was able to remain online and continue producing. A situation that would have taken weeks or months to diagnose with conventional methods was addressed in 12 hours at no additional cost—without interrupting cleanup. All brine volume was subsequently recovered before the well was placed on production.
After cleanup, the real-time acquisition and control (RTAC) system helped balance zonal contributions across all three laterals based on the observed flow performance in each of the six producing compartments. The productivity of each compartment was computed in real time and continuously monitored using production optimization digital workflows for intelligent completions. These early measurements combined with the enhanced control capability indicated the potential for significant improvement in production rate per unit length of reservoir contact.
