In April 1997, TOPCON, a joint venture of Texaco, Chevron and the Nigerian National Petroleum Corporation (NNPC), spudded the well Funiwa-43ML, offshore Nigeria. This multilateral well, with a level 5 junction, was drilled as a dual horizontal oil producer targeting an 11-foot thick oil column between gas and active water layers in an unconsolidated sandstone reservoir. The opposing laterals were 3052′ and 2242′ long horizontal sections respectively, within a ± 2-foot target window and were completed with 7″ slotted liner completions. Since the wellbore trajectories penetrated the reservoir's gas-cap prior to landing the well in the target oil column, the casing in the build sections was cemented to provide hydraulic isolation.

The junction in the main bore, from which the 2nd lateral was drilled, was created by milling a window in the casing with a drilling whipstock. This drilling whipstock was then replaced with a guidestock prior to running and cementing the 7″ liner in the 2nd lateral. The portion of the 7″ liner that extended back into the main bore was then washed over and retrieved along with the guidestock. This resulted in a full bore, full access junction providing mechanical support at the junction.

Completion equipment was then installed to hydraulically isolate the junction. This was achieved by running single string production packers below the junction in each lateral. Separate tubing strings were then tied-back, through the junction, to a dual string production packer above the junction. This resulted in the level 5 junction, ie.; a junction with mechanical and pressure integrity. The well was then completed as a dual string completion to surface.

This paper will describe the drilling and completion aspects of this project highlighting the construction of the junction thus allowing the well to be completed as a dual horizontal, dual completion multilateral well.

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