The First Multi-Lateral / Dual Completion Well in Saudi Arabia

Abstract

Abstract Recently Saudi Aramco completed the first multi-lateral / dual completion well with permanent segregated access and segregated production in one of its offshore fields in the Arabian Gulf region. The well presents a technical milestone to the company in the development of multiple reservoir fields. Also it demonstrated how new technological tools could be deployed effectively in an ideal situation to meet both reservoir and production requirements in a very cost-effective manner. Several systems were considered for this particular application which were thoroughly evaluated based on company requirements, cost, and immediate availability. Other considerations such as service company experience, number of jobs performed by service company and technical support were also part of the screening criteria. This paper presents Saudi Aramco's first and successful experience in the deployment of new acquired technology for the multi-lateral / dual completion systems. The screening criteria for selecting the system as well as the benefits realized and lessons learned from this experience are also discussed. Background The Berri field is located both onshore and offshore along the western edge of the Arabian Gulf. It is a multi-reservoir field (Figure-1), which contains oil-bearing reservoirs as well as gas reservoirs. The Berri field was the testing ground for the first horizontal well drilled in Saudi Aramco, the first horizontal sidetrack and now the first multilateral producer. A team consisting of representatives from reservoir, drilling, and production engineering was formed to recommend and pilot a system which would optimize the development of this multi-reservoir field and at the same time minimize the capital investment in the offshore area. To serve this purpose the multilateral / dual completion system was selected for the following main reasons:Increase the production rate from each well.Target multiple reservoirs in the same well.Eliminate the requirement for an additional production platform. The team selected a candidate well to apply the multi lateral / dual completion system on a pilot basis. The reservoir objectives from this well were as follows:Develop the area ahead of the upper reservoir (Hadriya) Flood front.Evaluate horizontal well performance in the lower Reservoir (Fadhili).Develop techniques to improve economics for the recovery of reserves from marginal zones to maintain field potential. The Fadhili reservoir has not been fully exploited yet due to the fact that it is thinner and of lesser quality than the Hadriya reservoir. Recompletions and drillstem tests in the field did not provide acceptable production rates to economically justify the drilling of a Fadhili horizontal well on a separate slot. Since there has not been a horizontal well in this reservoir and both reservoir and production parameters are not fully established, then anything less than a fully serviceable completion would not meet the objective of the proposed multi-lateral / dual completion well. Full flow control and pressure segregation was also absolutely required for Fadhili reservoir completion. The Berri field faces one other very unique challenge; that is the competition for investment against some of the lower operating cost fields within Saudi Aramco. This puts an extreme focus on efficiency in a field like Berri. To fully exploit all of the reservoirs in the Berri field on the long term the following requirements must be met:Reduce the cost of reaching the less prolific (Fadhili) reservoir.Reach the maximum number of reservoirs with each drilling slot.