Understanding pressure and pressure relationships is the key to safe well control. Yet, to date, the primary focus of well control has centred on recovery rather than prevention. Incidents related to loss of well control largely occur when the primary barrier, hydrostatic pressure from the drilling fluid, fails to prevent an influx; thus requiring the secondary barrier, closing of the BOPs, to engage in order stop the breach from becoming a full-blown, well control incident.
Influxes occur, most often, during the tripping operation where the swab effect lowers the bottomhole pressure below the formation’s pressure and can be commonly misidentified when “wellbore breathing,” nuisances gases, or cement setting are involved. Influxes can also occur when drilling into unexpected, higher-pressure zones. The unholy trinity of unknown pore pressure, unknown barrier conditions, and failure to diagnose an influx can converge into a significant cost impact at any time during the life cycle of the well and, in a worst-case scenario, culminate in tragic consequences.
The challenge for the future is that we should be able to go on to any operational rig and have the confidence to expect everyone involved in the operation to identify what minimum two barriers are in place at that time and what verification they have. This should be the expected norm with the demand for drilling in increasingly sensitive locations with higher-risk wells (HP/HT and deepwater).
This forum will address these issues and the current deficiencies in defining and maintaining wellbore barriers during the entire life cycle of the well—from spud to abandonment—and will discuss the gaps in the technical, human, process, and technology aspects of ensuring that wells are drilled to the highest and most consistent standards of safety. The forum will look at the full well life cycle of barriers in different drilling environments (Onshore/Offshore) under different scenarios such as: