A multilateral (MLT) well with an advanced intelligent completion string was recently completed in the Middle East. The well was designed as a "stacked?? dual producer in the upper and lower reservoir, and was drilled using the latest geo-steering techniques to accurately place the wellbore in a highly faulted and geologically complex structure. Rotary-steerable drilling systems (RSS) were used in several of the hole sections, along with advanced logging-while-drilling (LWD) tools including multi-pole acoustic, azimuthal deep resistivity, and resistivity at bit. Encounters with unstable shale and faults made the drilling difficult, but the decisions made in real-time to navigate the well resulted in a very high percentage of net pay in both laterals.
This well combined TAML Level 4 multilateral (MLT) technology with passive inflow control devices in the laterals and an advanced intelligent completion system in the mainbore. The TAML Level 4 multilateral junction was cemented to isolate unstable shale above the reservoir and to provide zonal isolation from the lateral completions, which were compartmentalized into stages with proprietary swellable packers and inflow control devices (ICDs). The intelligent completion was run in the mainbore with two interval control valves (ICVs) and isolation ball valve (LV ICV) to manage the production from each of the two laterals independently. The ICVs and LV ICV are controlled hydraulically through four control lines to surface, which were run in a flat-pack with one electric line to control a downhole gauge package for each lateral. Finally, the well was configured to allow the installation of a large electric submersible pump (ESP) to be run inside the upper 9-5/8-in. production tubing.
This project required intensive planning and coordination for more than a year in advance, which made the project successful despite the difficult drilling conditions and resulted in very little NPT for wellbore construction operations. This paper will focus on the planning, execution and lessons learned from the project.
In the existing horizontal wells in the target sand reservoir of the target field, premature water breakthrough caused the water cut trend to increase within months of production. . This occurred because the reservoir has a very high permeability sands along with active faults containing high viscous reservoir fluids.
New technologies were required to overcome the issue, maximize reservoir contact and enhance a more uniform oil production from a single location. Introducing the smart TAML Level-4 MLT well design to this reservoir along with inflow control device (ICD), inflow control valve (ICV), isolation ball valve (LV ICV) and other downhole gauges proved to be the optimum solution. It also aided in managing the production and the reservoir proactively to achieve maximum oil recovery. Moreover, drilling several laterals from a single wellbore with the ability to control production from both laterals had a great economic advantage because of the optimized cost effective field management.