Drilling system and method
First Claim
1. A system for drilling a well while injecting a drilling fluid through an injection line of said well and recovering through a return line of said well where the well being drilled is closed at all times comprises a pressure containment device and pressure/flow control device to a wellbore to establish/maintain a back pressure on the well, means to monitor the fluid flow in and out, means to monitor flow of any other material in and out, means to monitor parameters affecting the monitored flow value and means to predict a calculated value of flow out at any given time and to obtain real time information on discrepancy between predicted and monitored flow out and converting to a value for adjusting the pressure/flow control device and restoring the predicted flow value.
3 Assignments
0 Petitions
Accused Products
Abstract
A closed-loop drilling system and method of drilling oil, gas, or geothermal wells is described, whereby through the control of the flow rates in and out of the wellbore, and by adjusting the pressure inside the wellbore by a pressure/flow control device installed on the return line, surface pressure being increased or decreased as required, this in turn decreasing or increasing downhole pressure, occurrence of kicks and fluid losses may be greatly minimized and quickly controlled. Through the method of the invention the elimination of the kick tolerance and tripping margin on the design of the well is made possible, since the pore and fracture pressure will be determined in real-time while drilling the well, and, therefore, nearly no safety margin is necessary when designing the well, reducing significantly the number of casing strings necessary. The inventive method can be called intelligent safe drilling since the response to influx or fluid loss is nearly immediate and so smoothly done that the drilling can go on without any break in the normal course of action. The new method is applicable to the whole wellbore from the first casing string with a BOP connection, and it can be implemented and adopted to any rig or drilling installation that uses the conventional method with very few exceptions and limitations. The new method is applicable to all types of wells, onshore, offshore, deepwater and ultra-deepwater, with huge safety improvement in difficult drilling scenarios.
141 Citations
28 Claims
- 1. A system for drilling a well while injecting a drilling fluid through an injection line of said well and recovering through a return line of said well where the well being drilled is closed at all times comprises a pressure containment device and pressure/flow control device to a wellbore to establish/maintain a back pressure on the well, means to monitor the fluid flow in and out, means to monitor flow of any other material in and out, means to monitor parameters affecting the monitored flow value and means to predict a calculated value of flow out at any given time and to obtain real time information on discrepancy between predicted and monitored flow out and converting to a value for adjusting the pressure/flow control device and restoring the predicted flow value.
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2. A system of drilling a well while being drilled with a drill string having a drilling fluid circulated therethrough, while the well is kept closed at all times, wherein the system comprises:
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a) a pressure containment device;
b) a pressure/flow control device on the outlet stream;
c) means for measuring mass or volumetric flow and flow rate on the inlet and outlet streams to obtain real time mass or volumetric flow signals;
d) means for measuring mass or volumetric flow and flow rate of any other materials in and out;
e) means for directing all the flow, pressure and temperature signals so obtained to a central data acquisition and control system; and
f) a central data acquisition and control system programmed with a software that can determine a real time predicted out flow and compare it to the actual out flow estimated from the mass and volumetric flow rate values and other relevant parameters.
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3. A system of drilling a well while being drilled with a drill string having a drilling fluid circulated therethrough, while the well is kept closed at all times, wherein said system comprises:
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a) a pressure containment device;
b) a pressure/flow control device on the outlet stream;
c) means for measuring mass flow rate on the inlet and outlet streams;
d) means for measuring volumetric flow rate on the inlet and outlet streams;
e) at least one pressure sensor to obtain pressure data;
f) at least one temperature sensor to obtain temperature data;
g) a central data acquisition and control system that sets a value for an expected out flow and compares it to the actual out flow estimated from data gathered by the mass and volumetric flow rate meters as well as from pressure and temperature data, and in case of a discrepancy between the expected and actual flow values, adjusting the said pressure/flow control device to restore the outflow to the expected value. - View Dependent Claims (5, 6, 7)
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12. A method of drilling a well while being drilled with a drill string having a drilling fluid circulated therethrough, while the well is kept closed at all times, said method comprising the steps of:
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a) providing a pressure containment device to the wellbore;
b) providing a pressure/flow control device to control the flow out of the well and to keep a back pressure on the well;
c) providing a central data acquisition and control system and related software;
d) providing mass flow meters in both injection and return lines;
e) providing flow rate meters in both injection and return lines;
f) providing at least one pressure sensor;
g) providing at least one temperature sensor;
h) injecting drilling fluid through an injection line through which said fluid is made to contact said mass flow meters, said fluid flow meters, and said pressure and temperature sensors, and recovering drilling fluid through a return line;
i) collecting drill cuttings at the surface;
j) measuring the mass flow in and out of the well and collecting mass flow signals;
k) measuring the fluid flow rates in and out of the well and collecting fluid flow signals;
l) measuring pressure and temperature of fluid and collecting pressure and temperature signals;
m) directing all the collected flow, pressure and temperature signals to the said central data acquisition and control system;
n) the software of the central data acquisition and control system considering, at each time, the predicted flow out of the well;
o) having the actual and predicted out flows compared and checked for any discrepancy;
p) in case of a discrepancy, having a signal sent by the central data acquisition and control system to adjust the pressure/flow control device and restore the predicted out flow rate, without interruption of the drilling operation. - View Dependent Claims (14, 15, 16, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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13. A method of continuous, safe drilling of a well being drilled with a drill string having a drilling fluid circulated therethrough, while the well is kept closed at all times, said method comprising the steps of:
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a) providing a pressure containment device to the wellbore;
b) providing a pressure/flow control device to control the flow out of the well and to keep a back pressure on the well;
c) providing a central data acquisition and control system and related software;
d) providing mass flow meters in both injection and return lines;
e) providing flow rate meters in both injection and return lines;
f) providing at least one pressure sensor to measure pressure;
g) providing at least one temperature sensor to measure temperature;
h) injecting drilling fluid through an injection line through which said fluid is made to contact said mass flow meters, said fluid flow meters and said pressure and temperature sensors, and recovering drilling fluid through return line;
i) collecting drill cuttings at the surface;
j)measuring the mass flow in and out of the well and collecting mass flow signals;
k) measuring the fluid flow rates in and out of the well and collecting fluid flow signals;
l) measuring pressure and temperature of fluid and collecting pressure and temperature signals;
m) directing all the collected flow, pressure and temperature signals to the said central data acquisition and control system;
n) the software of the central data acquisition and control system considering, at each time, the predicted flow out of the well;
o) having the actual and predicted out flows compared and checked for any discrepancy;
p) in case of a discrepancy, having a signal sent by the central data acquisition and control system to adjust the pressure/flow control device and restore the predicted out flow rate without interruption of the drilling operation.
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27. A method for the real time determination of the fracture pressure of a well being drilled with a drill string and drilling fluid circulated therethrough, while the well is kept closed at all times, said method comprising the steps of:
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a) providing a pressure sensor at the bottom of the drill string;
b) having fluid and mass flow data generated collected and directed to a central data acquisition and control device that sets an expected value for fluid and mass flow;
c) the said central data acquisition and control device continuously comparing the said expected fluid and mass flow to the actual fluid and mass flow;
d) in case of a discrepancy between the expected and actual value, the said central data acquisition and control device activating a pressure/flow control device;
e) the detected discrepancy being a fluid loss, the value of the fracture pressure being obtained from a direct reading of the bottomhole pressure.
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28. A method for the real-time determination of the pore pressure of a well being drilled with a drill string and drilling fluid circulated therethrough, while the well is kept closed at all times, said method comprising the steps of:
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a) providing a pressure sensor at the bottom of the drill string;
b) having fluid and mass flow data generated collected and directed to a central data acquisition and control device that sets an expected value for fluid and mass flow;
c) the said central data acquisition and control device continuously comparing the said expected fluid and mass flow to the actual fluid and mass flow;
d) in case of a discrepancy between the expected and actual value, the said central data acquisition and control device activating a pressure/flow control device;
e) the detected discrepancy being an influx, the value of the pore pressure being obtained from a direct reading of the bottomhole pressure provided by the said pressure sensor.
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Specification