Mudline Managed Pressure Drilling and Enhanced Influx Detection

A method of manufacturing an offshore drilling installation configured to regulate a return mud flow close to the seabed, the method comprising:

• placing a sensor inside an annular space through which a return mud flow passes, close to the seabed, the sensor being configured to acquire values of at least one parameter related to the return mud flow;
• placing a valve near the sensor, the valve being configured to regulate the return mud flow;
• and
• connecting a controller to the valve and the sensor, the controller being configured to automatically control the valve to regulate the return mud flow towards achieving a value of a control parameter close to a predetermined value, based on the values received from the sensor.

A method of retrofitting an offshore drilling installation having a mud loop into a well and a plurality of blowout preventers (BOPs) located close to a seabed, the method comprising:

• placing a sensor below the BOPs, the sensor being configured to acquire values of at least one parameter related to a return mud flow;
• retrofitting one of the BOPs to operate as a valve configured to regulate the return mud flow;
• and
• connecting a controller located near the BOPs to the retrofitted BOP and the sensor, the controller being configured to automatically control the retrofitted BOP based on the values received from the sensor, to regulate the mud flow towards achieving a value of a control parameter close to a predetermined value.