Drilling system and method

Method for operating a well that is being drilled from a surface with a drill string to provide a wellbore having a drilling fluid circulated therethrough via inlet and outlet streams wherein the well is kept closed at all times, wherein the method comprises the use of a system comprising:

• a) a pressure containment device to the wellbore;
• b) means for measuring at least one of volumetric flow, mass flow, volumetric flow rate and mass flow rate on the inlet and outlet streams and obtaining flow or flow rate signals;
• c) at least one pressure sensor to obtain pressure signals;
• d) a central data acquisition and control system provided with software for predicting a real time signal;
• said method comprising the steps of
• a′) injecting drilling fluid through an injection line through which said fluid is made to contact at least one of said flow and flow rate means, and said pressure sensor, and recovering drilling fluid through a return line;
• b′) collecting drill cuttings at the surface;
• c′) measuring at least one of the volumetric flow and mass flow in and out of the well and collecting flow signals;
• d′) measuring pressure of fluid and collecting pressure signals;
• e′) directing all the collected signals to the said central data acquisition and control system;
• f′) the software of the central data acquisition and control system considering, at each time, a predicted signal;
• the system further comprising
• f) a pressure or flow control device on the outlet stream to control the flow out of the well and to keep a back pressure on the well;
• and wherein the central data acquisition and control unit is programmed to compare a real time predicted signal to the corresponding actual signal;
• the method further comprising
• having the actual and predicted signals compared and checked for any discrepancy;
• wherein the method and system act on the principle of volume or mass conservation, to determine the difference in volume or mass being injected and returned from the well;
• said determining compensates for factors including increase in hole volume, additional mass of rock returning as an indication of the nature of the fluid event occurring downhole;
• said comparison yielding any said discrepancy, said software also receiving as input any early detection parameters, wherein the input triggers a chain of investigation of probable scenarios, to ascertain that an influx or loss event has occurred;
• and converting said discrepancy to a value for adjusting the pressure or flow control device and restoring the predicted signal value, and
• in case of a discrepancy, having a signal sent by the central data acquisition and control system to adjust the pressure or flow control device and restore the predicted signal without interruption of the drilling operation, thereby preemptively adjusting backpressure to control the event.

Central data acquisition and control system for use in a system for operating a well while being drilled with a drill string to provide a wellbore having a drilling fluid circulated therethrough via inlet and outlet streams, wherein the well is kept closed at all times comprising:

• a) a pressure containment device which keeps the wellbore closed at all times while it is being drilled;
• b) means for measuring and monitoring at least one of volumetric flow, mass flow, volumetric flow rate and mass flow rate on the inlet and outlet streams to obtain flow signals, wherein monitoring means are located on lines in and out and are operated continuously throughout a given operation;
• c) at least one pressure sensor to obtain and monitor pressure signals, wherein a pressure monitoring sensor is located at the wellhead or at the bottomhole and is operated continuously throughout a given operation;
• d) a central data acquisition and control system;
• e) means for injecting the drilling fluid through an injection line through which said fluid is made to contact said volumetric or mass flow means, and said pressure sensor, and means for recovering drilling fluid through a return line;
• f) means for directing all the signals to the said central data acquisition and control system;
• the central data acquisition and control system provided with software for considering, at each time, a predicted signal;
• the system further comprising
• g) a pressure or flow control device on the outlet stream to control the flow out of the well and to keep a back pressure on the well;
• and the central data acquisition and control system being programmed to compare a real time predicted signal to the corresponding actual signal and check for any discrepancy;
• wherein the system acts on the principle of mass or volume conservation to determine the difference in mass or volume being injected and returned from the well;
• said determining compensates for factors including increase in hole volume, additional mass of rock returning as an indication of the nature of the fluid event occurring downhole,
• and to detect any discrepancy, and to receive as input any early detection parameters, wherein the input triggers a chain of investigation of probable scenarios, to ascertain that an influx or loss event has occurred,
• and convert said discrepancy to a value for adjusting the pressure or flow control device and restore the predicted signal value,
• and wherein the central data acquisition and control system comprises
• h) means, in case of a discrepancy, to send a signal to adjust the pressure or flow control device and restore the predicted signal value thereby preemptively adjusting backpressure at the surface to control the event without interruption of the drilling operation
• and wherein the system is a closed loop system, whereby monitoring means continuously provide data to the central data acquisition and control system whereby a predicted signal is continuously revised in response to any adjustment of actual signal value, adjusting ECD.

Method for operating a central data acquisition and control unit for use with a system for operating a well that is being drilled with a drill string to provide a wellbore having a drilling fluid circulate therethrough via inlet and outlet streams, wherein the well is kept closed at all times, wherein the system comprises:

• a) a pressure containment device which keeps the wellbore closed at all times while it is being drilled;
• b) means for measuring and monitoring at least one of mass flow, volumetric flow, mass flow rate and volumetric flow or rate on the inlet and outlet streams and obtaining flow signals, wherein monitoring means are located on lines in and out and are operated continuously throughout a given operation;
• c) at least one pressure sensor to obtain and monitor pressure signals, wherein the at least one pressure monitoring sensor is located at the wellhead or at the bottomhole and is operated continuously throughout a given operation;
• d) a central data acquisition and control system provided with software for predicting a real time signal;
• wherein the drilling of the well comprises the steps of
• injecting drilling fluid through an injection line through which said fluid is made to contact said mass or volumetric flow means, and said pressure sensor, and recovering the drilling fluid through a return line;
• collecting drill cuttings at the surface;
• measuring at least one of the mass flow, volumetric flow, mass flow rate and volumetric flow rate in and out of the well and collecting flow signals;
• measuring pressure of fluid and collecting pressure signals;
• directing all the signals to the said central data acquisition and control system;
• the software of the central data acquisition and control system considering, at each time, a predicted real time signal;
• the system further comprising
• e) a pressure or flow control device on the outlet stream to control the flow out of the well and to keep a back pressure on the well;
• and the central data acquisition and control unit being programmed to compare said real time predicted signal to the corresponding actual signal and check for any discrepancy;
• wherein the system acts on the principle of mass or volume conservation to determine the difference in mass or volume being injected and returned from the well;
• said determining compensates for factors including increase in hole volume, additional mass of rock returning as an indication of the nature of the fluid event occurring downhole;
• said comparison yielding any said discrepancy, said software also receiving as input any early detection parameters, wherein the input triggers a chain of investigation of probable scenarios, to ascertain that an influx or loss event has occurred;
• and converting said discrepancy to a value for adjusting the pressure or flow control device and restoring the predicted signal, and
• p) in case of a discrepancy, having a signal sent by the central data acquisition and control system to adjust the pressure or flow control device and restore the predicted signal thereby preemptively adjusting backpressure at the surface to control the event without interruption of the drilling operation
• and wherein the system is a closed loop system, whereby monitoring means continuously provide data to the central data acquisition and control system whereby a predicted signal is continuously revised in response to any adjustment of actual signal value, adjusting ECD.