Method and System for Monitoring Influx and Loss Events in a Wellbore

A method as claimed in any preceding claim, wherein prior to the step of comparing the measurement with an expected value for the measurement to provide a deviated measurement value, the method comprises determining the expected value for the measurement, preferably utilising measured flow in rate data and/or bit depth data and/or historical measurement data;

• and/or wherein prior to the step of comparing the measured pump pressure value with an expected pump pressure value to provide a deviated pump pressure value;
• the method comprises determining the expected pump pressure value, preferably utilising measured flow in rate data and/or bit depth data and/or historical pump pressure data.

A method as claimed in any preceding claim, wherein if it is established that an influx event or a loss event may have occurred, the method further comprises:

• raising an alarm, preferably by a visual or aural indicator;
• and/or writing in a database that it is established that an influx event or a loss event may have occurred
• and/or, dependent on claim dependency as appropriate, writing in the database at least some of the measured and determined values, measurements, volumes, pump pressures and flow out rates.

A method of monitoring for influx and/or loss events in a wellbore, comprising:

• receiving at least three independent measurements relating to fluid entering or leaving the wellbore;
• comparing each of at least two of these measurements with an expected value for that respective measurement to provide at least two respective deviated measurement values;
• establishing whether an influx event and/or establishing whether a loss event may have occurred based on these at least two deviated measurement values.