TO ENSURE maximum future hydrocarbon recovery from its fields, Saudi Aramco is increasing the number of laterals per well and equipping them with smart completions in their next-generation extreme reservoir contact (ERC) wells.
These extended reach wells, which can span for kilometres, decrease water production and improve sweep efficiency.
However, the challenge remains to obtain the required understanding of the laterals, as no technology exists to allow the multilateral well to be re-entered once the initial drillstring is removed. Operators have basically been locked out of their multilaterals.
To develop a targeted solution for this technical need, the Expec Advanced Research Centre (Expec Arc) Production Technology Team (PTT) and Welltec began in 2008 to identify the challenges associated with re-accessing the lateral sections so measurements may be taken.
“We designed a concept for a tool that could accurately locate and image the window in the casing, determine its orientation and steer the downhole tool string into the lateral monitored from the surface in real-time to gather the much needed data on the production process in real time,” says Mohamed Noui-Mehidi, PTT petroleum engineering specialist.
The joint project underwent rigorous design and testing challenges as it progressed through a series of milestones.
In December 2011, the first field test took place with the steerable access sub successfully imaging lateral windows and steering the tool string into two separate laterals. This is the first electro-mechanical system in the industry to allow on-demand access to and detection of the wellbore laterals, says Nabil AlHabib, PTT chief technologist.
The Saudi Arabian well test was accomplished with coiled tubing that powered the steerable access sub (SAS) assembly and pushed the system through various parts of the well and successfully accessed lateral holes.
Much of Aramco’s research at Expec Arc is long term and overcomes increasingly complex technical field challenges, says Samer AlAshgar, manager of Expec Arc.
“Milestones such as this steerable access sub are especially exciting and encourage our researchers to persevere in bringing our technology visions to reality and implementation in our fields,” he says.