Blow-Out Contingency Plan for a Deep Offshore Exploration Well

Planning a relief well in a new complex drilling environment is critical and require having all contingent solutions in place to limit HSE consequences of a potential dramatic drilling event. Typically, this would include:

• Specify the intercept well surface locations
• Plan for both intercept points (shallow & deep intercept).
• Detail the ranging and intercept strategies for both intercept points.
• Propose optimal survey program for the exploration well and for the probable intercept well level of uncertainty considering the possible ranging strategy and need for wellbore position accuracy.

Preliminary discussions with the operator and the institutions bring the understanding of the drilling environment and operational context. Then, this allows:

• Agreeing on the worst-case scenario that should be anticipated
• Defining all positional and directional constraints in term of DLS, wellbore architecture in accordance with operator.
• Planning optimized relief well trajectories in line with all defined directional constraints.
• Ensuring optimal alignment at interception point.
• Validating what capping equipment can be mobilized.
• Providing a realistic operational timeline.
• Proposition of an optimal survey program and ranging strategy for the exploration well.

Combined analyses regarding relief well drilling (with collision avoidance including survey program, ranging strategy...) and surface capping operations provide a complete understanding of the possible coactivity.

Surface positions were optimized in accordance and after various discussions with operator regarding the surface constraints.
The ranging strategy assumes that both active and passive magnetic ranging techniques are available to optimize drilling time to intercept.
PathControl allowed to assess the feasibility of the interception of the exploration well in case of uncontrolled blow-out thanks to its advanced knowledge of real relief well situations.