Saudi Aramco has employed horizontal sidetracking on existing dead vertical wells to enhance wells’ productivity and rejuvenate field's performance. Understanding flood front movement, inter-reservoir connectivity, and pressure propagation in a highly stratified clastic reservoir in mixed fluvial and aeolian depositional environments are the key parameters that led to successful deployment.

This paper will present a case example discussing development strategies to revive an idle vertical well that was shut-in due to high water cut and low oil productivity. Both dynamic and static data were integrated to describe fluid flow phenomenon in the area to provide better understanding of the geological model, sweep and oil recovery. The multidisciplinary study indicated lateral and vertical reservoir heterogeneity and multilayer reservoir compartmentalization that caused uneven flood front movement and inadequate pressure support.

The team has considered all the uncertainties involved and have formulated an optimum completion plan. The team recommended sidetracking the idle well about 1 km away to target a sweet spot through an aggressive step-out strategy. This long step-out strategy was the first to be implemented in this sandstone reservoir where risk of hole collapse or stuck pipe is extremely high. Prudent reservoir monitoring and applying safe drilling and mud management practices were the major elements to successfully achieve the objectives. The plan was carefully executed by deploying fit-for-purpose completion that consisted of premium sand screens and blank pipe with mechanical packers to isolate a wet zone. The well was then treated with a clean-up fluid to remove any mud filter-cake to enhance productivity. The current production performance exceeded expected rate by 100%. The success and the captured lessons-learned from this strategy will be capitalized on for implementation in future similar sidetrack opportunities.

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