It is usually an unnerving moment when a service tool is picked up, after a frac pack pumping operation with the goal to reach the "reverse position". The failure to establish this position could have significant undesirable consequences on the overall well objective, which could range from extensive fishing of the resulting stuck pipe to eventual loss of the well. It, therefore, becomes imperative for the completions planning team in collaboration with other relevant stakeholders to establish an "execution-friendly" reverse-out decision and communication protocol that will prevent a stuck situation. Agbami completions are mostly stacked frac pack with Intelligent Well Completion (IWC) capability to adequately control and monitor production. The first phase completion of the three-phased development was installed in 2007, while production commenced in 2008 [1]. A major consideration for the phased development campaign was to ensure lessons learned from one phase can be applied to the next. The 8-well Infill Drilling campaign was executed from 2017 to 2019 to capture un-swept oil and optimize production from the field. The Agbami frac service tools were successfully upgraded after the initial development phases and deployed on the infill campaign to mitigate the challenges encountered during the third phase frac pack installations. This upgrade, coupled with standardized processes, equipment, and procedures contributed to the improved frac pack installation performance recorded on the infill campaign. Despite the frac pack improvements, a near-miss on one of the completions could have resulted in a stuck service tool where an overpull of up to 160kips was required to move the service tool to reverse out excess proppant. It also took seven attempts and ∼105 kips overpull to move the shifter and close the FS2 fluid loss isolation valve. An investigation into this near-miss identified amongst other opportunities, a gap in the current communication protocol, and the need to improve the operations team's situational awareness of downhole conditions during pumping, at screen-out and at reverse-out. The team leveraged global initiatives on stuck service tool prevention and collaborated with service partners and the rig contractor to develop a fit-for-purpose reverse out and communication protocol. This protocol was successfully implemented in subsequent well completions. A "Frac Pack on Paper" meeting held with all relevant stakeholders: the rig crew; pumping and completion service companies; Chevron's Frac support group, and Chevron's completions and operations teams, to methodically go through the reverse-out and communication protocol which contributed immensely to the huge success achieved on the frac pack operations. The team's effective collaboration with service partners contributed to the ability to respond quickly to these challenges leading to continuous improvement in Agbami frac pack executions. This paper aims to discuss the Agbami stuck service tool challenges, causative factors, and mitigation steps successfully implemented.
Devotion of quality time, effort, and dedicated resources during the planning phase of frac or extension packed wells and establishing a clear communication path to a collaborative execution, will ensure the achievement of a successful stimulation with a reliable sand control. These diligent planning efforts become more crucial when faced with challenging thrust fault environments which can adversely affect the outcome of a frac or extension packs. Thrust faults traversing a target reservoir needs to be carefully evaluated for activation or uncontrollable fluid loss during the frac pack process to ensure adequate mitigation can be implemented for a successful job. This paper illustrates the systematic approach used to optimize sand control and productivity for a deepwater well including the following challenges that were encountered: TCP overbalance concerns, brine density, and the need to manage potential high fluid losses in a depleted zone (hydrostatic pressure less than 80 psi below estimated fracture pressure). Fracpack was designed without any frac length constraint. Gel concentration, pad volume and pump rate were maximized to manage low fluid efficiency. The job was pumped as per design with hard screenout at nominal rate, 70% of proppant placed behind casing and good annular pack. The well in question was an oil producer which was drilled with the wellbore crossing the main thrust fault at the reservoir level. It was drilled with no wellbore stability issues reported. The sand-face completion presented major challenges as summarized below. Lower Zone: short perforation interval that was 25 ft above the OWC and less than 80 ft away from the main thrust fault. Middle Zone: depleted sands with the main thrust fault crossing the wellbore few feet above the top perforation (top of the reservoir sand). Upper Zone: thrust fault was less than 90 ft away from the wellbore.
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