Genesis Project: Development Well Planning

Abstract

Abstract This paper discusses the development well planning for the Genesis Project which is a deepwater development project using a floating spar for simultaneous drilling and production operations. Included are geological and reservoir overviews, major equipment systems overviews, and well planning considerations for drilling and completion operations. Others involved in development well planning for deepwater developments can use the results of this work, and in particular, those developments considering utilization of a floating spar. Introduction The Genesis Project is the first deepwater development project in the world to use a floating spar with simultaneous drilling and production capabilities. The field is located in Green Canyon Blocks 160, 161, and 205 in the Gulf of Mexico. The development wells will be drilled and completed from the spar located in Green Canyon Block 205 in 2590 feet of water. The discovery well was drilled in 1988 and several delineation wells followed in the early 1990's. Development funding was approved in early 1996. A semi-submersible rig was used to batch set 36, 26, and 20 inch casing strings on 19 wells. The seafloor well pattern included locations for 20 wells and two export riser bases. One of the well locations in the pattern is actually one of the early delineation wells and was not included in the batch set program. Spacing between locations is 20 feet in a 140-foot diameter circle. A shallow water flow zone was successfully isolated on all batch set wells. The 26-inch casing was set just above the shallow water flow zone. Deepwater foam cementing was used to cement the 20-inch casing, set below the shallow water flow zone. A wellhead isolation system was also used to shut off the shallow water flow zone. In addition to the batch setting operations, the semisubmersible rig was used to drill the first two development wells with 9-5/8 inch production casing set at total depth. The batch setting and drilling of these first two wells was completed in the summer of 1997. The spar was installed in early summer of 1998 followed by topsides and rig installation. Hook up work commenced and the first rig operations, running the export risers, began in November, 1998. Geological Overview The Genesis Field is a major Plio-Pleistocene oil accumulation with five major sands (N1, N2, N3, 14,200', and 14,800') targeted for primary development. These sands were deposited as turbidites in bathyal water depths on the middle to lower continental slope. An eastward dipping series of combined structural and stratigraphic traps hold oil in columns up to 1400 feet in height. Small faults and stratigraphic barriers near or below the limit of seismic resolution may be an indication of significant reservoir compartmentalization.