Loss of Control Associated with Setting Surface Casing

Since 1995, incidents during or after cementing surface casing have continued to be one of the major causes of loss of control during drilling operations in the Gulf of Mexico. Of approximately 46 loss-of-well-control events since 1995, thirteen have been associated with surface casing cementing, with the most extreme consequences being broaching, surface boil, cratering, and fire, leading to major damage of a rig and adjacent platform. The MMS recently released Safety Alert No. 216 after another surface casing incident. The MMS reiterates those recommendations here.

1. For each well, the operators and contractors should conduct a review of the contingency procedures to be followed in the event of annular flow after cementing. Before using the diverter to hold back pressure after cementing, detailed planning is recommended, including identification of maximum pressure to be held, method of monitoring and measuring pressure, and how that pressure will be relieved or diverted if necessary.
    

2. The operators and contractors should ensure the contingency procedures are clearly disseminated to all rig supervisors and any personnel who could be involved in emergency decisions.
    

3. The operators and drilling contractors should ensure all supervisory personnel are fully trained in diverter operations specific to each rig, including pressure limits and control mechanisms, under all circumstances.
    

4. The operators should review cementing practices and procedures for shallow casing strings and adopt best cementing practices that provide the most protection from annular flow after cementing.