METHOD AND SYSTEM FOR IDENTIFYING A SELF-SUSTAINED INFLUX OF FORMATION FLUIDS INTO A WELLBORE
First Claim
1. A method of identifying a self-sustained influx of formation fluids into a wellbore (12) being drilled in a formation (14), the method comprising the steps of:
- closing an annular shut-off device (31) and diverting an annular return flow from the wellbore through a first flow rate measurement device (50, 58);
measuring a flow rate of said annular return flow;
measuring an inlet flow rate of fluids entering the well through a second flow rate measurement device (52) in a fluid injection line (48); and
identifying a self-sustained influx of formation fluids if a non-decreasing measured annular return flow rate is greater than said measured inlet flow rate.
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Accused Products
Abstract
A method of identifying a self-sustained influx of formation fluids into a wellbore includes the steps of closing an annular shut-off device and diverting an annular return flow from the wellbore through a first flow rate measurement device, measuring a flow rate of said annular return flow, measuring an inlet flow rate of fluids entering the well through a second flow rate measurement device in a fluid injection line, and identifying a self-sustained influx of formation fluids if a non-decreasing measured annular return flow rate is greater than said measured inlet flow rate.
11 Citations
22 Claims
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1. A method of identifying a self-sustained influx of formation fluids into a wellbore (12) being drilled in a formation (14), the method comprising the steps of:
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closing an annular shut-off device (31) and diverting an annular return flow from the wellbore through a first flow rate measurement device (50, 58); measuring a flow rate of said annular return flow; measuring an inlet flow rate of fluids entering the well through a second flow rate measurement device (52) in a fluid injection line (48); and identifying a self-sustained influx of formation fluids if a non-decreasing measured annular return flow rate is greater than said measured inlet flow rate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. In a well monitoring system (10) comprising:
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an annular shut-off device (31) arranged to close a wellbore annulus (18) of the well (12) from atmosphere; a flow control device line (56) coupled between said wellbore annulus and a surface fluid reservoir (42), said flow control device line including a flow control device (70); a fluid injection line (48) in fluid communication with an upper end (24) of the drillstring; an inlet flow rate measurement device (52) disposed in said fluid injection line, said inlet flow rate measurement device arranged to measure a flow rate in said fluid injection line and to generate a signal Fin(t) representative of actual fluid injection line flow rate as a function of time (t); a flow check line (57) disposed downhole from said annular shut-off device and coupled between said wellbore annulus and said surface fluid reservoir; and an outlet flow rate measurement device (58) disposed in said flow check line, said outlet flow rate measurement device arranged to measure flow rate in said flow check line and to generate a signal Fout(t) representative of actual flow check line flow rate as a function of time (t), a well monitoring method comprising the steps of, closing said annular shut-off device and diverting an annular return flow from the wellbore through said flow check line and outlet flow rate measurement device; measuring a flow rate of said annular return flow with said outlet flow rate measurement device; measuring an inlet flow rate of fluids entering the well with said inlet flow rate measurement device; and identifying a self-sustained influx of formation fluids if a non-decreasing measured annular return flow rate is greater than said measured inlet flow rate. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A well monitoring system (10) comprising:
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an annular shut-off device (31) arranged to close a wellbore annulus (18) of the well (12) from atmosphere; a flow control device line (56) coupled between said wellbore annulus and a surface fluid reservoir (42), said flow control device line including a flow control device (70); a fluid injection line (48) in fluid communication with an upper end (24) of the drillstring (20); an inlet flow rate measurement device (52) disposed in said fluid injection line, said inlet flow rate measurement device arranged to measure a flow rate in said fluid injection line and to generate a signal Fin(t) representative of actual fluid injection line flow rate as a function of time (t); a flow check line (57) disposed downhole from said annular shut-off device and coupled between said wellbore annulus and said surface fluid reservoir; an outlet flow rate measurement device (58) disposed in said flow check line, said outlet flow rate measurement device arranged to measure flow rate in said flow check line and to generate a signal Fout(t) representative of actual flow check line flow rate as a function of time (t); a central control unit arranged to receive said signals Fout(t) and Fin(t) and compute a delta between said signals Fout(t) and Fin(t); and a graphical user interface displaying said signals Fout(t) and Fin(t), wherein a self-sustained influx is identifiable on said graphical user interface to an operator if said displayed non-decreasing signal Fout(t) remains greater than said displayed signal Fin(t). - View Dependent Claims (22)
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Specification