Prevention of Well Control Incidents and Well Life Extension in Mature Fields

Abstract

Well Integrity issues associated with barrier degradation due to corrosion could significantly impact on production results in mature fields. Sometimes those issues may lead to the severe well control incidents during production phase affecting on the performance of the facilities nearby. This paper describes the negative trend of well control incidents, which was changed, by using innovative approach of secondary barrier evaluation for wells with compromised primary barrier envelope. The objective is to share with the audience special practice of well integrity management using multiple barrier evaluation technology to prevent loss of pressure containment (LOPC) incidents. In addition, the method allows to extend the production life of wells with sustained annulus pressure (SAP) and continue operating those wells under specific conditions and periodic monitoring instead of immediate killing and securing. This "grace period" could be granted based on the known conditions of the secondary barrier envelope until the rig become available to fix the integrity issue and restore the well barriers. Company started drilling activity in 1960's and since that time more than 4,000 wells have been drilled. All wells have carbon steel casings which serves as secondary barrier envelope in case primary barrier fail. Carbon steel easily gets corroded with time in case of insufficient protection and isolation from corrosive environment. Failure of both well barrier envelopes results in well control incidents. Uncontrolled release of hydrocarbons and other reservoir media to surface or aquifers has a strong negative HSE impact: it could be a reason for human injuries and deaths due to pressure, fire and H2S release, environment pollution, deferred production. Additionally, it is associated with unplanned increase in CAPEX and OPEX, reduction of business targets and KPI's, may cause negative impact on Company image and reputation. Innovative proactive method of secondary well barrier evaluation, successfully used to prevent well control incidents, allows Operators to find the right balance between safety and operation, and extend the production life of the wells with integrity issues without jeopardizing safety and integrity conditions in the fields. Paper illustrates how 9 well control incidents have been prevented and 14 wells with compromised primary barrier envelope were allowed to operate for a limited period of time, until the integrity issues have been fixed.