Results And Current Activity Of The Cost Well Program, Atlantic Outer Continental Shelf

Abstract

Abstract The Continental Offshore Stratigraphic Test (COST) program was begun as an expense-sharing method of drilling test wells to obtain scientific data on the rock strata beneath the frontier offshore areas of the United States. Four such wells have been drilled off the Atlantic coast in the last two years; these wells have been designated the COST B-2, drilled in the Baltimore Canyon area off New Jersey to 4,893 meters (16,043 feet), the COST G-1, drilled to 4,902 meters (16,071 feet) in the Georges Bank area, and the COST GE-1 which was drilled to 4,043 meters (13,254 feet) in the South Atlantic off Jacksonville, Florida. Data and analytical results of the COST B-2 were released in November, 1976, 60 days after the first Atlantic Outer Continental Shelf (OCS) lease sale. These data indicate that the Baltimore Canyon Trough area (Mid-Atlantic OCS) has the potential for oil and gas accumulation. The well penetrated about 1,403 meters (4,600 feet) of marine sandstone, shale, limestone of Tertiary age, about 946 meters (3,100 feet) of predominantly marine Upper Cretaceous sand stone and shale, and about 2,410 meters (7,900 feet) of nonmarine Lower Cretaceous sandstone, shale, and coal, Abundant potential reservoir rocks were encountered, along with adequate sealing beds and organic-rich potential source rocks. Results of the other COST wells will be released if and when future lease sales are held or five years after completion of the well. The drilling of the Atlantic COST wells have provided valuable geological and engineering provided valuable geological and engineering experience for future drilling on the Atlantic OCS. To date, there have been no indications of serious problems for deep drilling and no unexpected hazards. problems for deep drilling and no unexpected hazards. Weather and oceanographic data indicate that normal winter conditions will not cause lengthly drilling delays. Introduction The U.S. Atlantic Outer Continental Shelf (OCS) is slowly but surely moving from a completely unknown geological province to one in which at least regional dimensions and relationships are becoming known. Prior to 1976, the only subsurface data for this Prior to 1976, the only subsurface data for this nearly 518,000 square kilometer (200,000 square mile) offshore area consisted of regional geophysical surveys and extrapolated information from scattered coastal plain and Canadian OCS wells. However, since 1976, plain and Canadian OCS wells. However, since 1976, several deep stratigraphic wells have been drilled by the Continental offshore Stratigraphic Test (COST) Group and information is now available from the first of these test wells. The COST program was begun in 1974 as an expense sharing method of drilling test wells to obtain scientific data about the subsurface geology and potential resources of frontier offshore areas of the United States. Like other COST wells which have been drilled in the Gulf of Mexico, Southern California, and Alaskan OCS areas, the Atlantic wells were drilled "off structure" -i.e. away from any potential petroleum-bearing feature so that there would be a minimal petroleum-bearing feature so that there would be a minimal chance of encountering oil and gas while obtaining information on the regional stratigraphy, reservoir beds, and hydrocarbon potential. Four such wells have been completed to date off the Atlantic coast. These have been designated the COST B-2, drilled in the Baltimore Canyon area off New Jersey, The COST G-1 and COST G-2, both drilled in the Georges Bank area off Massachusetts, and the COST GE-1, located in the Southeast Georgia Embayment area off Jacksonville, Florida. Figure 1 shows the approximate locations of the Atlantic COST wells. All well depths are measured from the rig's kelly bushing. The COST B-2 Well was drilled to 4,893 meters (16,043 feet) using Southeastern Drilling Company's semi-submersible rig SEDCO J in 91 meters (298 feet) of water at a total cost of $8.4 million. The well is located at lat 39 deg. 22' 31.9" N. and long. 72 deg. 49' 03.8" W., approximately 147 kilometers (91 miles) east of Atlantic City, New Jersey.