The Ratawi reservoir in the Wafra field is a Lower Cretaceous oolitic limestone located in the Partitioned Neutral Zone between Kuwait and Saudi Arabia. The development of the field started with 95 vertical wells, which were drilled between 1956 and 1999. The strong water drive resulted in severe coning in the vertical wells in 1999, a very successful campaign of horizontal drilling commenced (new drilling and horizontal sidetracks). As a result, Ratawi production increased 50% in a 2-year period. The horizontal development plan can be divided into three phases: (1) 1999–2002: 53 horizontal wells were drilled geometrically, using only MWD/gammaray measurements; (2) 2003–2004: 41 wells were drilled using geostopping strategy based on resistivity; and (3) 2005 to present: 26 wells were drilled by geosteering, well placement, using the geological and log-while-drilling resistivity forward model. In this phase geosteering was crucial to remain in a very narrow target of ± 5 feet from the top of the pay zone and away from water coning, water breakthrough and the current oil water contact. Due to the successful implementation of the well placement services, all 20 planned horizontal sidetracks wells for 2007 will be drilled using this method. This case study highlights the benefits of steering in field development in terms of efficiency improvements in geological analysis. It also shows how well-steering decision-making maximized oil production through optimum well placement.


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