System for detecting blow out and lost circulation in a borehole

Claim 1

A method of detecting the commencement of blowouts and lost circulation in a borehole in which a drilling fluid is being circulated, comprising the steps of: transducing at a selected location within the borehole the rate of f1ow of the drilling fluid into the borehole into a first electrical signal proportiona1 thereto; accumulating said first electrical signals over a selected interval of time; transducing, at said selected location within the borehole, the rate of flow of the drilling fluid out of the borehole into a second electrical signal proportional thereto; accumulating said second electrical signals over a selected interval of time; comparing the accumulation of said first electrical signals with the accumulation of said second electrical signals to determine the differences in value therebetween, a preselected difference between the compared values being indicative of the commencement of one of a blow out and lost circulation, wherein said transducing steps comprise generating at a selected point within the borehole a sonic signal within the flowing streams of drilling fluid; receiving the sonic signals at a first point located a selected distance above said selected point and at a second point located the same selected distance below said selected point; measuring the time difference between reception of the sonic signal at said first and second points in the incoming fluid stream and transducing said first electrical signal in proportion thereto and in the outgoing fluid stream and transducing said second electrical signal in proportion thereto, and wherein said measuring step comprises triggering the generation of a ramp function simultaneously with the generation of said first sonic signal; accumulating the value of said ramp function in response to reception of said first sonic signal at said first point and accumulating the value of said ramp function in response to reception of said first sonic signal at said second point; comparing the value of said ramp functions after accumulation of each; and producing a first time difference signal proportional to the difference in the compared values of said accumulated ramp function values.

Claim 2

A method of detecting the commencement of blowouts and lost circulation in a borehole in which a drilling fluid is being circulated, comprising the steps of: transducing at a selected location within the borehole the rate of f1ow of the drilling fluid into the borehole into a first electrical signal proportiona1 thereto; accumulating said first electrical signals over a selected interval of time; transducing, at said selected location within the borehole, the rate of flow of the drilling fluid out of the borehole into a second electrical signal proportional thereto; accumulating said second electrical signals over a selected interval of time; comparing the accumulation of said first electrical signals with the accumulation of said second electrical signals to determine the differences in value therebetween, a preselected difference between the compared values being indicative of the commencement of one of a blow out and lost circulation, wherein said transducing steps comprise generating at a selected point within the borehole a sonic signal within the flowing streams of drilling fluid; receiving the sonic signals at a first point located a selected distance above said selected point and at a second point located the same selected distance below said selected point; measuring the time difference between reception of the sonic signal at said first and second points in the incoming fluid stream and transducing said first electrical signal in proportion thereto and in the outgoing fluid stream and transducing said second electrical signal in proportion thereto, and wherein said measuring step comprises triggering the generation of a ramp function simultaneously with the generation of said first sonic signal; accumulating the value of said ramp function in response to reception of said first sonic signal at said first point and accumulating the value of said ramp function in response to reception of said first sonic signal at said second point; comparing the value of said ramp functions after accumulation of each; and producing a first time difference signal proportional to the difference in the compared values of said accumulated ramp function values.

Claim 3

A method of detecting the commencement of blowouts and lost circulation in a borehole in which a drilling fluid is being circulated, comprising the steps of: transducing at a selected location within the borehole the rate of flow of the drilling fluid into the borehole into a first electrical signal proportional thereto; accumulating said first electrical signals over a selected interval of time; transducing, at said selected location within the borehole, the rate of flow of the drilling fluid out of the borehole into a second electrical signal proportional thereto; accumulating said second electrical signals over a selected interval of time; comparing the accumulation of said first electrical signals with the accumulation of said second electrical signals to determine the differences in value therebetween, a preselected difference between the compared values being indicative of the commencement of one of a blow out and lost circulation, wherein said transducing steps comprise generating at a selected point within the borehole a sonic signal within the flowing streams of drilling fluid; receiving the sonic signals at a first point located a selected distance above said selected point and at a second point located the same selected distance below said selected point; measuring the time difference between reception of the sonic signal at said first and second points in the incoming fluid stream and transducing said first electrical signal in proportion thereto and in the outgoing fluid stream and transducing said second electrical signal in proportion thereto, and wherein said measuring step comprises triggering the generation of a pair of ramp functions having identical slope simultaneously with the generation of said first sonic signal; interrupting one of said pair of ramp functions in response to reception of said first sonic signal at said first point and interrupting the other of said pair of ramp functions in response to reception of said first sonic signal at said second point; comparing the value of said one of said ramp functions with said other of said ramp functions after interruption of each; and producing a first time difference signal proportional to the difference in the compared values of said first and second ramp functions.

Claim 4

A method of detecting the commencement of blowouts and lost circulation in a borehole in which a drilling fluid is being circulated, comprising the steps of: transducing at a selected location within the borehole the rate of flow of the drilling fluid into the borehole into a first electrical signal proportional thereto; accumulating said first electrical signals over a selected interval of time; transducing, at said selected location within the borehole, the rate of flow of the drilling fluid out of the borehole into a second electrical signal proportional thereto; accumulating said second electrical signals over a selected interval of time; comparing the accumulation of said first electrical signals with the accumulation of said second electrical signals to determine the differences in value therebetween, a preselected difference between the compared values being indicative of the commencement of one of a blow out and lost circulation, wherein said transducing steps comprise generating at a selected point within the borehole a sonic signal within the flowing streams of drilling fluid; receiving the sonic signals at a first point located a selected distance above said selected point and at a second point located the same selected distance below said selected point; measuring the time difference between reception of the sonic signal at said first and second points in the incoming fluid stream and transducing said first electrical signal in proportion thereto and in the outgoing fluid stream and transducing said second electrical signal in proportion thereto, and wherein said measuring step comprises triggering the generation of a pair of ramp functions having identical slope simultaneously with the generation of said first sonic signal; interrupting one of said pair of ramp functions in response to reception of said first sonic signal at said first point and interrupting the other of said pair of ramp functions in response to reception of said first sonic signal at said second point; comparing the value of said one of said ramp functions with said other of said ramp functions after interruption of each; and producing a first time difference signal proportional to the difference in the compared values of said first and second ramp functions.

Claim 5

A method of detecting the commencement of blowouts and lost circulation in a borehole in which a drilling fluid is being circulated, comprising the steps of: transducing at a selected location within the borehole the rate of flow of the drilling fluid into the borehole into a first electrical signal proportional thereto; accumulating said first electrical signals over a selected interval of time; transducing, at said selected location within the borehole, the rate of flow of the drilling fluid out of the borehole into a second electrical signal proportional thereto; accumulating said second electrical signals over a selected interval of time; comparing the accumulation of said first electrical signals with the accumulation of said second electrical signals to determine the differences in value therebetween, a preselected difference between the compared values being indicative of the commencement of one of a blow out and lost circulation, wherein said first electrical signal transducing step comprises generating at a selected location within the borehole a first sonic signal within the stream of drilling fluid flow into the borehole; receiving the first sonic signal at a first point located a selected distance downstream of said selected location; receiving the first sonic signal at a second point located said selected distance upstream of said selected vertical location; measuring a first time difference between reception of the first sonic signal at said first point and at said second point; producing said first electrical signal proportional to the first time difference and wherein said second electrical signal transducing step comprises generating at said selected location within the borehole a plurality of sonic signals within the stream of drilling fluid flowing out of the borehole, each of said plurality of second sonic signals being generated at points equally circumferentially spaced from one another within the annular region through which drilling fluid flows toward the surface; receiving each of said plurality of second sonic signals at a first location spaced a selected distance downstream of said selected location, each of said plurality of sonic signals being received at points equally circumferentially spaced from one another within said annular region and in axial alignment with the respective points of generation; receiving each of said plurality of second sonic signals at a second location spaced said selected distance upstream of said location, each of said plurality of sonic signals being received at points equally circumferentially spaced from one another within said annular region and in axial alignment with the respective points of generation; measuring second time differences between reception of each of said plurality of second sonic signals at said first and second locations; averaging said time differences; and producing said second electrical signal proportional to the average time difference.

Claim 6

A method of detecting the commencement of blowouts and lost circulation in a borehole in which a drilling fluid is being circulated, comprising the steps of: transducing at a selected location within the borehole the rate of flow of the drilling fluid into the borehole into a first electrical signal proportional thereto; accumulating said first electrical signals over a selected interval of time; transducing, at said selected location within the borehole, the rate of flow of the drilling fluid out of the borehole into a second electrical signal proportional thereto; accumulating said second electrical signals over a selected interval of time; comparing the accumulation of said first electrical signals with the accumulation of said second electrical signals to determine the differences in value therebetween, a preselected difference between the compared values being indicative of the commencement of one of a blow out and lost circulation, wherein said first electrical signal transducing step comprises generating at a selected location within the borehole a first sonic signal within the stream of drilling fluid flow into the borehole; receiving the first sonic signal at a first point located a selected distance downstream of said selected location; receiving the first sonic signal at a second point located said selected distance upstream of said selected vertical location; measuring a first time difference between reception of the first sonic signal at said first point and at said second point; producing said first electrical signal proportional to the first time difference and wherein said second electrical signal transducing step comprises generating at said selected location within the borehole a plurality of sonic signals within the stream of drilling fluid flowing out of the borehole, each of said plurality of second sonic signals being generated at points equally circumferentially spaced from one another within the annular region through which drilling fluid flows toward the surface; receiving each of said plurality of second sonic signals at a first location spaced a selected distance downstream of said selected location, each of said plurality of sonic signals being received at points equally circumferentially spaced from one another within said annular region and in axial alignment with the respective points of generation; receiving each of said plurality of second sonic signals at a second location spaced said selected distance upstream of said location, each of said plurality of sonic signals being received at points equally circumferentially spaced from one another within said annular region and in axial alignment with the respective points of generation; measuring second time differences between reception of each of said plurality of second sonic signals at said first and second locations; averaging said time differences; and producing said second electrical signal proportional to the average time difference.

Claim 11

A method of detecting the commencement of blowouts and lost circulation in a borehole in which a drilling fluid is being circulated, comprising the steps of: transducing at a selected location within the borehole the rate of flow of the drilling fluid into the borehole into a first electrical signal proportional thereto; accumulating said first electrical signals over a selected interval of time; transducing, at said selected location within the borehole, the rate of flow of the drilling fluid out of the borehole into a second electrical signal proportional thereto; accumulating said second electrical signals over a selected interval of time; comparing the accumulation of said first electrical signals with the accumulation of said second electrical signals to determine the differences in value therebetween, a preselected difference between the compared values being indicative of the commencement of one of a blow out and lost circulation, wherein said first electrical signal transducing step comprises generating at a selected location within the borehole a first sonic signal within the stream of drilling fluid flow into the borehole; receiving the first sonic signal at a first point located a selected distance downstream of said selected location; receiving the first sonic signal at a second point located said selected distance upstream of said selected vertical location; measuring a first time difference between reception of the first sonic signal at said first point and at said second point; producing said first electrical signal proportional to the first time difference and wherein said second electrical signal transducing step comprises generating at said selected location within the borehole a second sonic signal within the stream of drilling fluid flow out of the borehole; receiving the second sonic signal at a first point located said selected distance upstream of said selected location; measuring a second time difference between reception of said second sonic signal at said first point and at said second point; producing said second electrical signal proportional to the second time difference, and wherein said second difference measuring step comprises triggering the generation of ramp functions simultaneously with the generation of said second sonic signal; accumulating the value of said ramp function in response to reception of said second sonic signal at said first point and accumulating the value of said ramp function in response to reception of said second sonic signal at said second point; comparing the values of said second ramp function after accumulation of each; and producing a second time difference signal proportional to the difference in the compared values of said accumulated ramp functions.

Claim 12

A method of detecting the commencement of blowouts and lost circulation in a borehole in which a drilling fluid is being circulated, comprising the steps of: transducing at a selected location within the borehole the rate of flow of the drilling fluid into the borehole into a first electrical signal proportional thereto; accumulating said first electrical signals over a selected interval of time; transducing, at said selected location within the borehole, the rate of flow of the drilling fluid out of the borehole into a second electrical signal proportional thereto; accumulating said second electrical signals over a selected interval of time; comparing the accumulation of said first electrical signals with the accumulation of said second electrical signals to determine the differences in value therebetween, a preselected difference between the compared values being indicative of the commencement of one of a blow out and lost circulation, wherein said first electrical signal transducing step comprises generating at a selected location within the borehole a first sonic signal within the stream of drilling fluid flow into the borehole; receiving the first sonic signal at a first point located a selected distance downstream of said selected location; receiving the first sonic signal at a second point located said selected distance upstream of said selected vertical location; measuring a first time difference between reception of the first sonic signal at said first point and at said second point; producing said first electrical signal proportional to the first time difference and wherein said second electrical signal transducing step comprises generating at said selected location within the borehole a second sonic signal within the stream of drilling fluid flow out of the borehole; receiving the second sonic signal at a first point located said selected distance upstream of said selected location; measuring a second time difference between reception of said second sonic signal at said first point and at said second point; producing said second electrical signal proportional to the second time difference, and wherein said second difference measuring step comprises triggering the generation of ramp functions simultaneously with the generation of said second sonic signal; accumulating the value of said ramp function in response to reception of said second sonic signal at said first point and accumulating the value of said ramp function in response to reception of said second sonic signal at said second point; comparing the values of said second ramp function after accumulation of each; and producing a second time difference signal proportional to the difference in the compared values of said accumulated ramp functions.

Claim 13

A method of detecting the commencement of blowouts and lost circulation in a borehole in which a drilling fluid is being circulated, comprising the steps of: transducing at a selected location within the borehole the rate of flow of the drilling fluid into the borehole into a first electrical signal proportional thereto; accumulating said first electrical signals over a selected interval of time; transducing, at said selected location within the borehole, the rate of flow of the drilling fluid out of the borehole into a second electrical signal proportional thereto; accumulating said second electrical signals over a selected interval of time; comparing the accumulation of said first electrical signals with the accumulation of said second electrical signals to determine the differences in value therebetween, a preselected difference between the compared values being indicative of the commencement of one of a blow out and lost circulation, wherein said first electrical signal transducing step comprises generating at a selected location within the borehole a first sonic signal within the stream of drilling fluid flow into the borehole; receiving the first sonic signal at a first point located a selected distance downstream of said selected location; receiving the first sonic signal at a second point located said selected distance upstream of said selected vertical location; measuring a first time difference between reception of the first sonic signal at said first point and at said second point; producing said first electrical signal proportional to the first time difference and wherein said second electrical signal transducing step comprises generating at said selected location within the borehole a second sonic signal within the stream of drilling fluid flow out of the borehole; receiving the second sonic signal at a first point located said selected distance upstream of said selected location; measuring a second time difference between reception of said second sonic signal at said first point and at said second point; producing said second electrical signal proportional to the second time difference, and wherein said second time difference measuring step comprises triggering the generation of a pair of ramp functions having identical slope simultaneously with the generation of said second sonic signal; interrupting one of said pair of ramp functions in response to reception of said second sonic signal at said first point and interrupting the other of said pair of ramp functions in response to reception of said second sonic signal at said second point; comparing the value of said first and second ramp functions after interruption of each; and producing a second time difference signal proportional to the difference in the compared values of said first and second ramp functions.

Claim 14

A method of detecting the commencement of blowouts and lost circulation in a borehole in which a drilling fluid is being circulated, comprising the steps of: transducing at a selected location within the borehole the rate of flow of the drilling fluid into the borehole into a first electrical signal proportional thereto; accumulating said first electrical signals over a selected interval of time; transducing, at said selected location within the borehole, the rate of flow of the drilling fluid out of the borehole into a second electrical signal proportional thereto; accumulating said second electrical signals over a selected interval of time; comparing the accumulation of said first electrical signals with the accumulation of said second electrical signals to determine the differences in value therebetween, a preselected difference between the compared values being indicative of the commencement of one of a blow out and lost circulation, wherein said first electrical signal transducing step comprises generating at a selected location within the borehole a first sonic signal within the stream of drilling fluid flow into the borehole; receiving the first sonic signal at a first point located a selected distance downstream of said selected location; receiving the first sonic signal at a second point located said selected distance upstream of said selected vertical location; measuring a first time difference between reception of the first sonic signal at said first point and at said second point; producing said first electrical signal proportional to the first time difference and wherein said second electrical signal transducing step comprises generating at said selected location within the borehole a second sonic signal within the stream of drilling fluid flow out of the borehole; receiving the second sonic signal at a first point located said selected distance upstream of said selected location; measuring a second time difference between reception of said second sonic signal at said first point and at said second point; producing said second electrical signal proportional to the second time difference, and wherein said second time difference measuring step comprises triggering the generation of a pair of ramp functions having identical slope simultaneously with the generation of said second sonic signal; interrupting one of said pair of ramp functions in response to reception of said second sonic signal at said first point and interrupting the other of said pair of ramp functions in response to reception of said second sonic signal at said second point; comparing the value of said first and second ramp functions after interruption of each; and producing a second time difference signal proportional to the difference in the compared values of said first and second ramp functions.

Claim 15

A system for detecting the commencement of blowouts and lost circulation in a borehole in which a drilling fluid is being circulated, comprising: means for transducing at a selected location within the borehole the rate of flow of the drilling fluid into the borehole into a first electrical signal proportional thereto; means for accumulating said first electrical signal over a selected interval of time; means for transducing, at said selected location within the borehole, the rate of flow of the drilling fluid out of the borehole into a second electrical signal proportional thereto; means for accumulating said second electrical signals over a selected interval of time; means for comparing the accumulation of said first electrical signals with the accumulation of said second electrical signals to determine the differences in value therebetween, a preselected difference between the compared values being indicative of the commencement of one of a blow out and lost circulation, wherein said first electrical signal transducing means comprises means for generating at a selected location within the borehole a first sonic signal within the stream of drilling fluid flow into the borehole; means for receiving the first sonic signal at a first point located a selected distance downstream of said selected location; means for receiving the first sonic signal at a second point located said selected distance upstream of said selected location; means for measuring a first time difference between reception of the first sonic signal at said first point and at said second point; means for producing said first electrical signal proportional to the first time difference, wherein said first time difference measuring means comprises means for triggering the generation of a ramp function simultaneously with the generation of said first sonic signal; means for accumulating the value of said ramp function in response to reception of said first sonic signal at said first point; means for accumulating the value of said ramp function in response to reception of said first sonic signal at said second point; means for comparing the accumulated values; and means for producing a first time difference signal proportional to the difference in the compared accumulated values.

Claim 16

A system for detecting the commencement of blowouts and lost circulation in a borehole in which a drilling fluid is being circulated, comprising: means for transducing at a selected location within the borehole the rate of flow of the drilling fluid into the borehole into a first electrical signal proportional thereto; means for accumulating said first electrical signal over a selected interval of time; means for transducing, at said selected location within the borehole, the rate of flow of the drilling fluid out of the borehole into a second electrical signal proportional thereto; means for accumulating said second electrical signals over a selected interval of time; means for comparing the accumulation of said first electrical signals with the accumulation of said second electrical signals to determine the differences in value therebetween, a preselected difference between the compared values being indicative of the commencement of one of a blow out and lost circulation, wherein said first electrical signal transducing means comprises means for generating at a selected location within the borehole a first sonic signal within the stream of drilling fluid flow into the borehole; means for receiving the first sonic signal at a first point located a selected distance downstream of said selected location; means for receiving the first sonic signal at a second point located said selected distance upstream of said selected location; means for measuring a first time difference between reception of the first sonic signal at said first point and at said second point; means for producing said first electrical signal proportional to the first time difference, wherein said first time difference measuring means comprises means for triggering the generation of a ramp function simultaneously with the generation of said first sonic signal; means for accumulating the value of said ramp function in response to reception of said first sonic signal at said first point; means for accumulating the value of said ramp function in response to reception of said first sonic signal at said second point; means for comparing the accumulated values; and means for producing a first time difference signal proportional to the difference in the compared accumulated values.

Claim 17

A system for detecting the commencement of blowouts and lost circulation in a borehole in which a drilling fluid is being circulated, comprising: means for transducing at a selected location within the borehole the rate of flow of the drilling fluid into the borehole into a first electrical signal proportional thereto; means for accumulating said first electrical signal over a selected interval of time; means for transducing, at said selected location within the borehole, the rate of flow of the drilling fluid out of the borehole into a second electrical signal proportional thereto; means for accumulating said second electrical signals over a selected interval of time; means for comparing the accumulation of said first electrical signals with the accumulation of said second electrical signals to determine the differences in value therebetween, a preselected difference between the compared values being indicative of the commencement of one of a blow out and lost circulation, wherein said first electrical signal transducing means comprises means for generating at a selected location within the borehole a first sonic signal within the stream of drilling fluid flow into the borehole; means for receiving the first sonic signal at a first point located a selected distance downstream of said selected location; means for receiving the first sonic signal at a second point located said selected distance upstream of said selected location; means for measuring a first time difference between reception of the first sonic signal at said first point and at said second point; means for producing said first electrical signal proportional to the first time difference, and wherein said first time difference measuring means comprises means for triggering the generation of a pair of ramp functions having identical slopes simultaneously with the generation of said first sonic signal; means for interrupting one of said pair of ramp functions in response to reception of said first sonic signal at said first point; means for interrupting the other of said pair of ramp functions in response to reception of said first sonic signal at said second point; means for comparing the value of said one of said other ramp functions after interruption of each; and means for producing a first time difference signal proportional to the difference in the compared values of said first and second ramp functions.

Claim 18

A system for detecting the commencement of blowouts and lost circulation in a borehole in which a drilling fluid is being circulated, comprising: means for transducing at a selected location within the borehole the rate of flow of the drilling fluid into the borehole into a first electrical signal proportional thereto; means for accumulating said first electrical signal over a selected interval of time; means for transducing, at said selected location within the borehole, the rate of flow of the drilling fluid out of the borehole into a second electrical signal proportional thereto; means for accumulating said second electrical signals over a selected interval of time; means for comparing the accumulation of said first electrical signals with the accumulation of said second electrical signals to determine the differences in value therebetween, a preselected difference between the compared values being indicative of the commencement of one of a blow out and lost circulation, wherein said first electrical signal transducing means comprises means for generating at a selected location within the borehole a first sonic signal within the stream of drilling fluid flow into the borehole; means for receiving the first sonic signal at a first point located a selected distance downstream of said selected location; means for receiving the first sonic signal at a second point located said selected distance upstream of said selected location; means for measuring a first time difference between reception of the first sonic signal at said first point and at said second point; means for producing said first electrical signal proportional to the first time difference, and wherein said first time difference measuring means comprises means for triggering the generation of a pair of ramp functions having identical slopes simultaneously with the generation of said first sonic signal; means for interrupting one of said pair of ramp functions in response to reception of said first sonic signal at said first point; means for interrupting the other of said pair of ramp functions in response to reception of said first sonic signal at said second point; means for comparing the value of said one of said other ramp functions after interruption of each; and means for producing a first time difference signal proportional to the difference in the compared values of said first and second ramp functions.

Claim 19

A system for detecting the commencement of blowouts and lost circulation in a borehole in which a drilling fluid is being circulated, comprising: means for transducing at a selected location within the borehole the rate of flow of the drilling fluid into the borehole into a first electrical signal proportional thereto; means for accumulating said first electrical signal over a selected interval of time; means for transducing, at said selected location within the borehole, the rate of flow of the drilling fluid out of the borehole into a second electrical signal proportional thereto; means for accumulating said second electrical signals over a selected interval of time; means for comparing the accumulation of said first electrical signals with the accumulation of second electrical signals to determine the differences in value therebetween, a preselected difference between the compared values being indicative of the commencement of one of a blow out and lost circulation, wherein said first electrical signal transducing means comprises means for generating at a selected location within the borehole a first sonic signal within the stream of drilling fluid flow into the borehole; means for receiving the first sonic signal at a first point located a selected distance downstream of said selected location; means for receiving the first sonic signal at a second point located said selected distance upstream of said selected location; means for measuring a first time difference between reception of the first sonic signal at said first point and at said second point; means for producing said first electrical signal proportional to the first time difference, and wherein said second electrical signal transducing means comprises means for generating at said selected location within the borehole a plurality of sonic signals within the stream of drilling fluid flow out of the borehole, each of said plurality of second sonic signals being generated at points equally circumferentially spaced from one another within the annular region through which drilling fluid flows toward the surface; means for receiving each of said plurality of second sonic signals at a first location spaced at a selected distance downstream of said selected location, each of said plurality of sonic signals being received at points equally circumferentially spaced from one another within said annular region and in axial alignment with the respective points of generation; means for receiving each of said plurality of second sonic signals at a second location spaced said selected distance upstream of said selected location, each of said plurality of sonic signals being received at points equally circumferentially spaced from one another within said annular region and in axial alignment with the respective points of generation; means for measuring the time differences between reception of each of said plurality of second sonic signals at said first and second locations; means for averaging said time differences; and means for producing said second electrical signal proportional to the average time difference.

Claim 20

A system for detecting the commencement of blowouts and lost circulation in a borehole in which a drilling fluid is being circulated, comprising: means for transducing at a selected location within the borehole the rate of flow of the drilling fluid into the borehole into a first electrical signal proportional thereto; means for accumulating said first electrical signal over a selected interval of time; means for transducing, at said selected location within the borehole, the rate of flow of the drilling fluid out of the borehole into a second electrical signal proportional thereto; means for accumulating said second electrical signals over a selected interval of time; means for comparing the accumulation of said first electrical signals with the accumulation of second electrical signals to determine the differences in value therebetween, a preselected difference between the compared values being indicative of the commencement of one of a blow out and lost circulation, wherein said first electrical signal transducing means comprises means for generating at a selected location within the borehole a first sonic signal within the stream of drilling fluid flow into the borehole; means for receiving the first sonic signal at a first point located a selected distance downstream of said selected location; means for receiving the first sonic signal at a second point located said selected distance upstream of said selected location; means for measuring a first time difference between reception of the first sonic signal at said first point and at said second point; means for producing said first electrical signal proportional to the first time difference, and wherein said second electrical signal transducing means comprises means for generating at said selected location within the borehole a plurality of sonic signals within the stream of drilling fluid flow out of the borehole, each of said plurality of second sonic signals being generated at points equally circumferentially spaced from one another within the annular region through which drilling fluid flows toward the surface; means for receiving each of said plurality of second sonic signals at a first location spaced at a selected distance downstream of said selected location, each of said plurality of sonic signals being received at points equally circumferentially spaced from one another within said annular region and in axial alignment with the respective points of generation; means for receiving each of said plurality of second sonic signals at a second location spaced said selected distance upstream of said selected location, each of said plurality of sonic signals being received at points equally circumferentially spaced from one another within said annular region and in axial alignment with the respective points of generation; means for measuring the time differences between reception of each of said plurality of second sonic signals at said first and second locations; means for averaging said time differences; and means for producing said second electrical signal proportional to the average time difference.

Claim 26

A system for detecting the commencement of blowouts and lost circulation in a borehole in which a drilling fluid is being circulated, comprising: means for transducing at a selected location within the borehole the rate of flow of the drilling fluid into the borehole into a first electrical signal proportional thereto; means for accumulating said first electrical signal over a selected interval of time; means for transducing, at said selected location within the borehole, the rate of flow of the drilling fluid out of the borehole into a second electrical signal proportional thereto; means for accumulating said second electrical signals over a selected interval of time; means for comparing the accumulation of said first electrical signals with the accumulation of said second electrical signals to determine the differences in value therebetween, a preselected difference between the compared values being indicative of the commencement of one of a blow out and lost circulation, wherein said first electrical signal transducing means comprises means for generating at a selected location within the borehole a first sonic signal within the stream of drilling fluid flow into the borehole; means for receiving the first sonic signal at a first point located a selected distance downstream of said selected location; means for receiving the first sonic signal at a second point located said selected distance upstream of said selected location; means for measuring a first time difference between reception of the first sonic signal at said first point and at said second point; means for producing said first electrical signal proportional to the first time difference, wherein said second electrical signal transducing means comprises means for generating at said selected location within the borehole a second sonic signal within the stream of drilling fluid flow out of the borehole; means for receiving the second sonic signal at a first point located said selected distance upstream of said selected location; means for measuring a second time difference between reception of said second sonic signal at said first point and at said second point; means for producing said second electrical signal proportional to the second time difference, and wherein said second time difference measuring means comprises means for triggering the generation of a pair of ramp functions having identical slope simultaneously with the generation of said second sonic signal; means for interrupting one of said pair of ramp functions in response to reception of said second sonic signal at said first point and interrupting the other of said pair of ramp functions in response to reception of said second sonic signal at said second point; means for comparing the value of said first and second ramp functions after interruption of each; and means for producing a second time difference signal proportional to the difference in the compared values of said first and second ramp functions.

Claim 27

A system for detecting the commencement of blowouts and lost circulation in a borehole in which a drilling fluid is being circulated, comprising: means for transducing at a selected location within the borehole the rate of flow of the drilling fluid into the borehole into a first electrical signal proportional thereto; means for accumulating said first electrical signal over a selected interval of time; means for transducing, at said selected location within the borehole, the rate of flow of the drilling fluid out of the borehole into a second electrical signal proportional thereto; means for accumulating said second electrical signals over a selected interval of time; means for comparing the accumulation of said first electrical signals with the accumulation of said second electrical signals to determine the differences in value therebetween, a preselected difference between the compared values being indicative of the commencement of one of a blow out and lost circulation, wherein said first electrical signal transducing means comprises means for generating at a selected location within the borehole a first sonic signal within the stream of drilling fluid flow into the borehole; means for receiving the first sonic signal at a first point located a selected distance downstream of said selected location; means for receiving the first sonic signal at a second point located said selected distance upstream of said selected location; means for measuring a first time difference between reception of the first sonic signal at said first point and at said second point; means for producing said first electrical signal proportional to the first time difference, wherein said second electrical signal transducing means comprises means for generating at said selected location within the borehole a second sonic signal within the stream of drilling fluid flow out of the borehole; means for receiving the second sonic signal at a first point located said selected distance upstream of said selected location; means for measuring a second time difference between reception of said second sonic signal at said first point and at said second point; means for producing said second electrical signal proportional to the second time difference, and wherein said second time difference measuring means comprises means for triggering the generation of a pair of ramp functions having identical slope simultaneously with the generation of said second sonic signal; means for interrupting one of said pair of ramp functions in response to reception of said second sonic signal at said first point and interrupting the other of said pair of ramp functions in response to reception of said second sonic signal at said second point; means for comparing the value of said first and second ramp functions after interruption of each; and means for producing a second time difference signal proportional to the difference in the compared values of said first and second ramp functions.

Claim 28

A system for detecting the commencement for blowouts and lost circulation in a borehole in which a drilling fluid is being circulated, including a sub having a coupling on each end for incorporation into the drill pipe string of a borehole drilling rig, said sub including an upper end, a lower end, a generally cylindrical outer surface, and a central axial passageway for conducting the flow of drilling into the borehole, said system comprising: an inner sonic transducer positioned at a central location within the sub within the central passageway for transmitting a sonic signal through the downwardly flowing drilling fluid toward both the upper and lower ends of the sub; a pair of inner sonic receivers for detecting the sonic signal transmitted from said inner transducer, one of said receivers being located within the central passageway near the upper end of the sub a selected distance from the inner transmitter and the other receiver being located within the central passageway near the lower end of the sub said selected distance from the inner transmitter; an outer sonic transducing means positioned at said central location of the sub on the cylindrical outer surface for transmitting a sonic signal through the upwardly flowing drilling fluid toward both the upper and lower ends of the sub; a pair of outer sonic receiving means for detecting the sonic signal transmitted by said outer transducing means, one of said receiving means being located on the outer surface of the sub near the upper end said selected distance from the outer transmitter and the other receiving means also being located on the outer surface of the sub near the lower end of the sub said selected distance from the outer transmitter; means for measuring a first time difference between reception of the inner sonic signal by the lower inside receiver and by the upper inside receiver; means for producing an input fluid flow rate signal proportional to said first time difference; means for measuring a second time difference between reception of the outer sonic signal by the lower outer receiving means and by the upper outer receiving means; means for producing an output fluid flow rate signal proportional to said second time difference; means for accumulating input flow rate signals and output flow rate signals; and means for comparing said accumulation of input flow rate signals and said accumulation of output flow rate signals to determine the differences in value therebetween, a preselected difference between the compared values being indicative of the commencement of one of a blowout and lost circulation.

Claim 29

A system for detecting the commencement for blowouts and lost circulation in a borehole in which a drilling fluid is being circulated, including a sub having a coupling on each end for incorporation into the drill pipe string of a borehole drilling rig, said sub including an upper end, a lower end, a generally cylindrical outer surface, and a central axial passageway for conducting the flow of drilling into the borehole, said system comprising: an inner sonic transducer positioned at a central location within the sub within the central passageway for transmitting a sonic signal through the downwardly flowing drilling fluid toward both the upper and lower ends of the sub; a pair of inner sonic receivers for detecting the sonic signal transmitted from said inner transducer, one of said receivers being located within the central passageway near the upper end of the sub a selected distance from the inner transmitter and the other receiver being located within the central passageway near the lower end of the sub said selected distance from the inner transmitter; an outer sonic transducing means positioned at said central location of the sub on the cylindrical outer surface for transmitting a sonic signal through the upwardly flowing drilling fluid toward both the upper and lower ends of the sub; a pair of outer sonic receiving means for detecting the sonic signal transmitted by said outer transducing means, one of said receiving means being located on the outer surface of the sub near the upper end said selected distance from the outer transmitter and the other receiving means also being located on the outer surface of the sub near the lower end of the sub said selected distance from the outer transmitter; means for measuring a first time difference between reception of the inner sonic signal by the lower inside receiver and by the upper inside receiver; means for producing an input fluid flow rate signal proportional to said first time difference; means for measuring a second time difference between reception of the outer sonic signal by the lower outer receiving means and by the upper outer receiving means; means for producing an output fluid flow rate signal proportional to said second time difference; means for accumulating input flow rate signals and output flow rate signals; and means for comparing said accumulation of input flow rate signals and said accumulation of output flow rate signals to determine the differences in value therebetween, a preselected difference between the compared values being indicative of the commencement of one of a blowout and lost circulation.