Horizontal wells have dominated conventional wells because of their increased production rates, improved recovery efficiency, increased reservoir drainage area, and delayed gas and water coning. However, nonuniform-flow profiles can result in premature water/ gas production, loss of production and reserves, and a decrease in profitability, which will shorten the life, and defeat the purpose, of a horizontal well.This paper describes a new production-technology system that will optimize production, delay water/gas coning, eliminate/ minimize annular flow, and ensure uniform inflow along the lateral at the cost of a minute pressure drop in long, high-rate horizontal wells. A case history is presented in which this production technology, combined with sand-control technology, has resulted in significant savings for the operator and improved production in offshore horizontal oil wells.

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This paper describes the unique development plan of the M field, a giant offshore field with an areal extent of more than 800 square kilometers (km 2 ), laying under shallow waters northeast of Saudi Arabia. Due to the large number of wells to be drilled, conventional offshore development methods required over 30 offshore platforms to meet the production target efficiently. However, a novel drilling island concept in the form of a causeway was adopted, since the shallow water areas do not allow ocean vessels to set up the jackets and platforms. Utilization of a causeway, combined with the implementation of ultra extended reach drilling (ERD), reduced offshore operations to 11 platforms resulting in enormous savings to the operator.The backbone of the upstream infrastructure is the 20 kilometers (km) long, 11 meter (m) wide main causeway, and 25 drilling islands linked to it through 21 km of lateral causeways. The task of constructing these structures involves movement of more than 40 million cubic meters of sand and rock. The main causeway includes a 2,400 m bridge, in addition to five 150 m and eight 50 m bridges for minimal environmental impact on marine life.Being one of the largest drilling projects to be undertaken, with various reservoir, ERD, and logistical challenges were encountered during the planning and initial execution phases of the project. Meeting the expected production rate, at the lowest development and operating costs, in the safest and most environmental-friendly manner were the main drivers for the current plan. Reservoir heterogeneity, torque and drag, hydraulics, rigs specifications, well intervention, waste management and other specific challenges were overcome successfully using different techniques that are discussed in depth in the paper. OTC 20112Causeway and Offshore. This option involved constructing 27 man-made islands with 40% onshore development. The islands were to be connected with a causeway to allow easier future accessibility.Onshore, Causeway and Offshore. The final option was to maximize the use of the coast line by introducing ultra extended reach wells. This scenario would result in over 70% being onshore development.Evaluation. The whole life cycle costs were evaluated for the three options and assessed program estimates and construction risks in reaching its conclusion.The causeway had the lowest capital expenses, in addition to considerable reduction in operational expenses (40% of the project would be onshore operations). This option also allowed for a large number of drilling slots for future wells to maintain potential. Finally, applying extended reach drilling added significant additional savings.The conventional offshore operations requires normal high safety measures, however, causeway utilization is a unique operation in many aspects. Consequently, a Risk Assessment (RA) study was conducted by a third party consultant for drilling at onshore sites and causeway islands to identify hazards and minimize risks to by implementing safe guards. The major challenge was...