The assurance of well integrity in the oil and gas fields has become a paramount responsibility during the field life cycle. Today this task represent a major challenge in the oil industry taking in consideration the rising of number of wells with extreme conditions with HPHT reservoirs, high fracture pressures, highly sour environments and subsea wells in ultra deep waters. After the catastrophic incident of Macondo in 2010, Process Safety (PS) and Well Integrity (WI), are the two major priorities of all Oil & Gas Companies, due to the potentially high financial and environmental impacts, in case a well barrier failure occur.

The management of the wells barrier represents one of the main targets inside the oil industry, in order to guarantee the integrity on the oil and gas wells. New standards highlight the requirement of to guarantee two barriers all the time in order to avoid any undesirable leakage of well fluids. The policy of ensuring two barriers is mandatory, and the aim is to have available a secondary barrier in case the primary barrier fail. However, immediately after any failure in the primary barrier, is also mandatory start up an emergency plan in order to recovery the primary barrier or suspend the Well properly with two temporary barriers. The emergency plan to re-establish two well barriers normally requires some special resources and an extensive risk assessment. The first challenge after the emergency plan has been activated is how to define an adequate and safer setup for the well intervention, in order to guarantee personnel safety and the integrity of the assets.

This technical paper propose a new approach for the Hydraulic Workover interventions and a workflow to enhance the Hydraulic Workover Units (HWOU) in order to make those operations safer, reliable and suitable to attend challenging interventions to restore wells with integrity issues and flexible enough and cost effective to attend conventional workovers. The idea is to develop an enhanced HWOU to compete with Rig, Hoist and CTU in different intervention scenarios. It’s presented an outline of the improvements, job analyis and the risk assessment required to define an adequate well control envelop in order to cover all the changes in the well barriers, the changes on well conditions and the expected challenges along the intervention. At the end we present the recipe to conduct the evaluation of every intervention and the tailored improvements to the intervention challenges.

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