Well bore force-measuring apparatus

Claim 2

Apparatus adapted for measuring at least one downhole load condition while drilling a borehole and comprising: a drill string having a borehole-drilling device dependently coupled to the lower end thereof and defining a fluid passage for circulating drilling fluids between the surface end of said drill string and said borehole-drilling device; an elongated load-responsive member having opposite end portions respectively secured to spaced portionS of said drill string and cooperatively arranged for normally maintaining said loadresponsive member in tension and an unrestrained intermediate portion adapted to vary in tension in response to increases and decreases in loads imposed on said drill string tending to move said spaced portions thereof in relation to one another; transducer means coupled to said intermediate portion of said load-responsive member and having a measurable characteristic adapted for varying in response to changes in the tensile forces in said load-responsive member occurring upon relative movement between said spaced portions of said drill string; acoustic-signaling means on said drill string operatively coupled to said transducer means and cooperatively arranged for producing acoustic signals representative of variations in said measurable characteristic in drilling fluids flowing through said drill string; and acoustic signal-detecting means operatively coupled to said surface end of said drill string and cooperatively arranged for detecting said acoustic signals.

Claim 3

The load-measuring apparatus of claim 1 wherein said load-responsive member is normally tensioned to about half of its yield point.

Claim 4

The load-measuring apparatus of claim 1 further including: means on said load-responsive member cooperatively arranged for concentrating strain in said intermediate portion thereof upon changes in the loads imposed on said drill string.

Claim 5

The load-measuring apparatus of claim 1 wherein said opposite end portions of said load-responsive member are spaced longitudinally from one another so that changes in axial loads imposed on said drill string will cause said load-responsive member to proportionally contract and elongate as such axial loads increase and decrease; and said transducer means include at least one tension-responsive strain gage mounted on said intermediate portion of said load-responsive member and cooperatively arranged for responding primarily to contraction and elongation thereof.

Claim 6

The load-measuring apparatus of claim 1 wherein said opposite end portions of said load-responsive member are angularly aligned and spaced longitudinally from one another so that changes in torsional loads imposed on said drill string will cause said load-responsive member to proportionally twist and untwist as such torsional loads increase and decrease; and said transducer means include at least one torsion-responsive strain gage mounted on said intermediate portion of said load-responsive member and cooperatively arranged for responding primarily to variations in the torsional forces acting thereon.

Claim 7

The load-measuring apparatus of claim 1 wherein said opposite end portions of said load-responsive member are angularly aligned and spaced longitudinally from one another so that changes in torsional loads imposed on said drill string will cause said load-responsive member to proportionally twist and untwist as such torsional loads increase and decrease and changes in axial loads imposed on said drill string will cause said load-responsive member to proportionally contract and elongate as such axial loads increase and decrease; and said transducer means include at least one torsion-responsive strain gage mounted on said intermediate portion of said load-responsive member and cooperatively arranged for responding primarily to variations in the torsional forces acting on said load-responsive member, and at least one tension-responsive strain gage mounted on said intermediate portion of said load-responsive member and cooperatively arranged for responding primarily to variations in the tensile forces acting on said load-responsive member upon contraction and elongation thereof.

Claim 8

The load-measuring apparatus of claim 1 wherein said load-responsive member is exterior of said drill string; and further including: a sleeve member cooperatively arranged around said load-responsive member and having upper and lower end portions respectively extending above and Below said spaced portions of said drill string; first and second means respectively fluidly sealing said upper and lower end portions of said sleeve member to said drill string for defining an enclosed chamber around said load-responsive member; and pressure-regulating means cooperatively arranged on said drill string and adapted for maintaining said enclosed chamber at an elevated pressure about equal to the pressure of drilling fluids flowing through said drill string.

Claim 9

Apparatus adapted for measuring at least one downhole load condition while drilling a borehole and comprising: a multi-sectional drill string having a borehole-drilling device dependently coupled to the lower end thereof and defining a fluid passage for circulating drilling fluids between the surface end of said drill string and said borehole-drilling device; a tubular load-bearing body tandemly coupled between adjacent sections of said drill string and having a longitudinal bore for conducting drilling fluids between said drill string sections; a load-responsive sleeve coaxially arranged on said load-bearing body and having upper and lower end portions respectively secured rigidly to longitudinally-spaced upper and lower portions of said load-bearing body for normally maintaining said load-responsive sleeve in tension and a reduced-thickness intermediate portion adapted to deform in response to loads imposed on said load-bearing body tending to move one of said spaced body portions in relation to the other of said spaced body portions; electrical transducer means cooperatively arranged on said intermediate portion of said load-responsive sleeve and having a varying electrical characteristic proportional to changes in the tension in said load-responsive sleeve occurring upon variations in loads acting on said load-bearing body; acoustic-signaling means on said drill string operatively coupled to said transducer means and cooperatively arranged for producing acoustic signals representative of variations in said measurable characteristic in drilling fluids flowing through said drill string; and acoustic signal-detecting means operatively coupled to said surface end of said drill string and cooperatively arranged for detecting said acoustic signals to provide surface indications of loads imposed on said drill bit through said drill string.

Claim 10

Apparatus adapted for measuring at least one downhole load condition while drilling a borehole and comprising: a multi-sectional drill string having a borehole-drilling device dependently coupled to the lower end thereof and defining a fluid passage for circulating drilling fluids between the surface end of said drill string and said borehole-drilling device; a tubular load-bearing body tandemly coupled between adjacent sections of said drill string and having a longitudinal bore for conducting drilling fluids between said drill string sections; a load-responsive sleeve coaxially arranged on said load-bearing body and having upper and lower end portions respectively secured rigidly to longitudinally-spaced upper and lower portions of said load-bearing body for normally maintaining said load-responsive sleeve in tension and a reduced-thickness intermediate portion adapted to deform in response to loads imposed on said load-bearing body tending to move one of said spaced body portions in relation to the other of said spaced body portions; electrical transducer means cooperatively arranged on said intermediate portion of said load-responsive sleeve and having a varying electrical characteristic proportional to changes in the tension in said load-responsive sleeve occurring upon variations in loads acting on said load-bearing body; acoustic-signaling means on said drill string operatively coupled to said transducer means and cooperatively arranged for producing acoustic signals representative of variations in said measurable characteristic in drilling fluids flowing through said drill string; and acoustic signal-detecting means operatively coupled to said surface end of said drill string and cooperatively arranged for detecting said acoustic signals to provide surface indications of loads imposed on said drill bit through said drill string.

Claim 11

The load-measuring apparatus of claim 8 wherein said load-responsive sleeve is exterior of said load-bearing body.

Claim 12

The load-measuring apparatus of claim 8 further including: a tubular housing cooperatively arranged around said load-responsive sleeve; first and second means respectively fluidly sealing the upper and lower end portions of said tubular housing to said load-bearing body above and below said load-responsive sleeve for defining an enclosed chamber therearound; and pressure-equalizing means on said load-bearing body and cooperatively arranged for maintaining said enclosed chamber at an elevated pressure at least about equal to the pressure of drilling fluids flowing through said longitudinal bore.

Claim 13

The load-measuring apparatus of claim 8 wherein said electrical transducer means include: at least one tension-responsive strain gage mounted on said intermediate portion of said load-responsive sleeve and cooperatively arranged for responding to contraction and elongation of said load-responsive sleeve caused by changes in axial loads imposed on said load-bearing body.

Claim 14

The load-measuring apparatus of claim 8 wherein said electrical transducer means include: at least one set of tension-responsive strain gages mounted on said intermediate portion of said load-responsive sleeve and cooperatively arranged for responding to angular twisting and untwisting of said load-responsive sleeve caused by changes in torsional loads imposed on said load-bearing body.

Claim 15

The load-measuring apparatus of claim 12 wherein said electrical transducer means further include: at least one tEnsion-responsive strain gage mounted on said intermediate portion of said load-responsive sleeve and cooperatively arranged for responding to contraction and elongation of said load-responsive sleeve caused by changes in axial loads imposed on said load-bearing body.

Claim 16

The load-measuring apparatus of claim 13 wherein said load-responsive sleeve is exterior of said load-bearing body.

Claim 17

The load-measuring apparatus of claim 14 further including: at least one tension-responsive strain gage mounted on said intermediate portion of said load-responsive sleeve and cooperatively arranged for responding to contraction and elongation of said load-responsive sleeve caused by changes in axial loads imposed on said load-bearing body.