Solid Expandable Tubular Systems Extend the Life of Mature Fields
Being able to capitalize on advantageous mechanical isolation technologies has been the catalyst for some operators to utilize existing wellbores to optimize field recoveries from different reservoirs. An innovative application that installed over 1,400 ft of solid expandable tubulars enabled Marathon Oil Gabon Limited (MOGL) to simultaneously isolate a sour zone produced through casing perforations and segregate a previously repaired multi-stage cementing collar in their Tchatamba South B2 sidetrack (TCTS B2st) well in Gabon. The solid expandable cased-hole liner allowed MOGL to develop a lower zone and continue producing from the existing well. This value-added approach was even more economically prudent because MOGL used a hydraulic workover unit (HWO) in this well intervention as an alternative to a conventional rig. The increasing cost and unavailability of drilling and workover rigs, mainly offshore, have become contributing obstacles for well intervention and well repairs in mature fields. In this case solid expandable tubulars mitigated production problems and extended the life of the well with lowered costs and increased reliability. This paper describes the safe and successful installation of a solid expandable tubular system that isolated six individual sets of perforations into four intervals. This system also reinforced the integrity of a previously repaired, multi-stage cementing collar, accomplishing both objectives with a minimum reduction to the existing inside diameter (ID) of the wellbore. The paper also details how this enabling technology allowed MOGL to perforate and produce a deeper zone thus optimizing reserve recovery in a mature field.