Because intelligent wells include complex assemblies, engineers typically rely on computer programs to help them select, coordinate and manage them. These software programs allow designers to import wellbore and trajectory information into modeling programs that are used to create and analyze various casing and tubing designs. Available reservoir—data such as number and depths of zones, oil and gas gravities, hydrocarbon composition, initial and final reservoir pressures and productivity indexes—are used as input for production modeling.
Using production models, operators are able to calculate total flow rate and production contribution from each zone. They can then add restraints to the design, such as the number of control lines available or the number of zones to be produced, and choose the well design and production scenario that optimizes hydrocarbon recovery. By varying choke settings within the model, the operator can observe the impact on individual zonal contribution and overall production and customize flow control valve settings before the wells are completed.
To maximize the benefits of real-time downhole monitoring and control capabilities, operators must process and act on a significant volume of data throughout the life of the well. To accomplish this, downhole data are sent to operator offices through supervisory control and data acquisition (SCADA) systems, where they are analyzed using production optimization software. A steady-state, multiphase flow simulator uses modeling algorithms for nodal analysis to compare the data with those expected from optimal settings and take corrective actions such as changing choke settings and flow rates at one or more intervals.
In some advanced systems, the operator inputs a target production rate or other parameters such as water production levels, and the program adjusts the down-hole chokes to achieve the desired result. The target parameter may be set for a zone, well or entire field. Software programs designed for intelligent well control and monitoring may be expanded fieldwide to notify operators of equipment performance deviations or to capture production trends in the field over time.
Refining the System
As a consequence of the development of more precise remote monitoring, control capabilities and design and management software, operators now deploy ICs in a variety of well types, not only to minimize interventions but also to optimize operating efficiency and production. At the same time, the E&P industry is shifting from analog to digital data recording, providing operators with a tool for integrating and processing large amounts of data from many sources. The ability to treat these data from a fieldwide perspective has been critical in allowing operators to realize the full potential of ICs and, by extension, the reservoirs the completions are designed to access.
The latest iteration of IC systems includes in situ measurements of pressure, temperature, flow rate and water cut across the formation face in each zone of each lateral. All sensors are packaged in a single station together with an electric flow control valve that has infinitely variable settings controlled from the surface through a single electric control line. This ability to monitor and control large numbers of zones in a well has significantly increased operator production and reservoir management in heterogeneous or multilayered reservoirs and in extended-reach developments.
Oilfield Review 2016.
Copyright © 2016 Schlumberger.
For help in preparation of this article, thanks to Adrian Francis, Houston, Texas, USA.