Hoover-Diana is a deepwater Gulf of Mexico oil and gas development. The reservoir development plan is a hybrid drilling and completion program encompassing remote subsea wells (Diana) connected by flowlines to a host DDCV (deep draft caisson vessel) and platform-type wells (Hoover) on the DDCV with surface trees connected to the seafloor by production risers.The Diana subsea wells were batch drilled with a dynamically-positioned drillship and then completed with a new-build, moored semisubmersible. These subsea wells were designed as horizontal open-hole gravel packs to deplete a relatively thin oil rim that lies between an aquifer and a large gas cap. The horizontal sections of each well were drilled and completed with the subsea tree in place, and all wells were flowed back to the drilling rig for clean-up and hydrate prevention prior to installation of the DDCV and flowlines. At the time, these were the deepest water-depth horizontal wells in the world. Numerous challenges were encountered in the design and construction of these wells, including the scheduling aspects associated with the two deepwater drilling rigs and pipeline installation vessels.The Hoover drilling program required significant upgrades of an existing API-type platform rig combined with unique modifications to accommodate DDCV motions and riser systems. The Hoover drilling and completion program is a mixture of cased-hole frac pack wells and open-hole, horizontal gravel pack wells. Furthermore, it marks the first time a drilling rig would set subsea wellheads from a caisson vessel and perform all of the drilling and completion operations including the riserless operations.

Openhole gravel pack (OHGP) completions are often selected as the preferred completion technique to provide long life, high capacity, low skin completions. One drawback to OHGPs, however, is the inability to isolate undesirable water or gas within the completion interval whether it is identified during the initial completion or during any point in the production lifecycle of the well. With the recent introduction of a broad suite of Alternate Path ® Technology (APT) tools, the added functionality of true openhole zonal isolation can now be combined with the reliability of gravel packing to deliver unparalleled, long-term completion capabilities.With the advancement of the new openhole shunt packer with APT, wells have been successfully completed to provide capability for future isolation depending on production results of the well. The shunt packer can be run through 9 5 ⁄8-in casing, set before gravel packing begins, and form a seal against the borehole to provide annular isolation in either round or oval hole sizes up to 10¾-in. These openhole packers have been recently combined with shunted blank joints to provide upfront isolation of unwanted water or gas found while drilling the completion interval to increase well production rate and/or estimated ultimate recovery (EUR). This paper will describe the first installations of the equipment which combined internally shunted sand screens, openhole shunt packers, and shunted blank pipe to fully isolate water and gas sands within a completion interval while enabling a full gravel pack across the remaining completion.