Case study of geosteering a horizontal well in western Nigeria

This paper reviews the process and results of geosteering a horizontal well in Nigeria—specifically well FY-133, one of a series of wells planned for Forcardos Yokri Field which straddles the mouth of a river in coastal waters. To date, about 150 wells have been drilled in the field. Eight have been abandoned for reasons of safety or because of the absence of hydrocarbons. FY-133 was planned as a horizontal well that was to be drilled from the southeast toward the northwest. The target reservoir, the D-5.0 sand, is the largest in the field with approximately 50% of the field stock tank of oil initially in place (STOIIP). StrataSteer was utilized to position the well to maximize recovery. The software operates with Sperry-Sun downhole tools and the INSITE information system. A data link in INSITE provides real-time data.