Exxon Production Research Company

John L Evans

Larry Rayner Russell

Jerry M Speers

George F Gehrig

An apparatus and method for preventing damage to the mechanical components of a borehole inclinometer is disclosed. The inclinometer uses a freely suspended pendulum to align with the vertical at a selected position in the borehole. A compass connected to the pendulum rotates to an orientation defined by the earth's magnetic field. To protect the components which suspend the pendulum, the pendulum is clamped between a timer and a lens as the inclinometer is lowered into the borehole. At a selected time, the pendulum is unclamped and is permitted to reach an equilibrium, measuring position. After a selected interval, the timer urges the pendulum against the lens to clamp the pendulum. The inclinometer is raised from the wellbore, and the orientation of the pendulum relative to the lens is observed to determine the azimuth and inclination of the borehole.

Magnetic single shot inclinometer

A method and apparatus for establishing the rate at which fluid is transferred between a borehole 14 and the surrounding formations 16 in the course of moving drill string 20 upward or downward in the borehole 14. A bell nipple 40 is situated at the upper portion of the borehole 14. While tripping, drilling fluid is circulated into the borehole 14 and exits through an outflow port 44 in the bell nipple 40. The level of drilling fluid is maintained constant at the outflow port 44. Meters 52, 52', 54 are provided to measure inflow and outflow rates. Circuitry 66 is provided to establish the volume rate at which the amount of drill string 20 within the borehole 14 changes. The outputs of the meters 52, 52', 54 and rate establishing means 66 are summed to establish the compensated rate at which fluid is transferred between the formations 16 and the borehole 14. This compensated rate is compared to an alarm limit. An alarm 76 is activated if the compensated rate exceeds the alarm limit.

Method and apparatus for monitoring fluid flow between a borehole and

A method for controlling the flow of drilling fluid through a subaqueous wellbore is disclosed. The method comprises the steps of continuously measuring the output flow rate (A) of the drilling fluid from the wellbore, the input flow rate (B) of the drilling fluid to the wellbore, and at least a component of the pitch and roll (P/R) of the vessel, computating a floating alarm limit (C) dependent upon the pitch and roll (P/R) signal and the roughness of the sea, filtering the periodic fluctuation of the output flow rate (A) due to the motion of the vessel, and computating the delta flow signal (D) by subtracting the input flow rate (B) from the filtered output flow rate (A). The method further comprises the step of generating a signal whenever the absolute value of the delta flow rate (D) exceeds the floating alarm limit (C) to provide a visible warning that the flow of drilling fluid is out of control and to either close off the wellbore in case of a kick or to stop the flow of fluid and stop drilling in case of lost returns. Apparatus for controlling the flow of drilling fluid through a subaqueous wellbore is disclosed while drilling from a floating vessel. The wellbore is connected to the lower end of the drill string and the lower end of an annulus by a valve through which the drilling fluid flows. The upper end of the annulus is connected to a conduit from which the drilling flows to the suction side of a pump which circulates the drilling fluid therefrom into the upper end of the drill string, through the wellbore, and back up the annulus into the conduit. The apparation comprises an output flow meter connected to the exit of the conduit, an input flow meter connected between the pump and the upper end of the drill string, means mounted on the vessel for sensing the pitch and roll of the vessel, and computer means for receiving the output flow rate (A) signal from the output flow meter, the input flow rate (B) from the input flow meter, and the pitch and roll (P/R) signal from the pitch and roll sensing means. The computer means calculates an alarm limit (C) based on the pitch and roll (P/R) signal and the roughness of the sea continuously filters the periodic fluctuation of the output flow rate (A) due to the motion of the vessel, computes the delta flow signal (D) by subtracting the input flow rate (B) from the filtered output flow rate (A), and generates a signal whenever the delta flow rate (D) exceeds the floating alarm limit (C) to provide a warning of a possible blowout or lost circulation condition and to either close off the wellbore in case of a kick or to stop the flow of fluid and stop drilling in case of lost returns.

Growing community of inventors

Houston, TX, United States of America

John L Evans