Monitoring fluids in a borehole

Claim 2

In a method of monitoring fluids and flow in a borehole penetrating subterranean formations including the steps of emplacing a plurality of acoustic transducers that are spaced apart longitudinally of said borehole and in a down-hole tool at at least one location in said borehole, transmitting and receiving acoustic energy between said spaced-apart acoustic transducers, generating functions that are related to the transmitted and received acoustic energy, transmitting the functions to equipment at the surface for meaningful observation and for preserving a record if desired, the improvement comprising: a. transmitting acoustic energy of a predetermined frequency through said fluids in said borehole between said transducers, said acoustic energy having a first portion traveling along the longitudinal axis of said borehole and downstream, and a second portion traveling along the longitudinal axis of said borehole and upstream; b. discriminating said first and second portions of acoustic energy arriving through the fluid column in said borehole; and detecting from said first and second portions of acoustic energy arriving at the respective transducer operating as a receiver apparent frequency affording information as to frequency shift which is related to fluid flow velocity, and amplitude which is related to fluid density.

Claim 3

The method of claim 1 wherein continuous acoustic energy is employed.

Claim 4

The method of claim 1 wherein said plurality of acoustic transducers are traversed along a longitudinal axis of said borehole.

Claim 5

The method of claim 3 wherein continuous acoustic energy is employed.

Claim 6

Apparatus for measuring flow velocity and density of fluids in a borehole penetrating subterranean formations comprising: a. down-hole tool having a plurality of transducers adapted for directionally transmitting and receiving acoustic energy primarily through said fluids therebetween, and for transmitting a first portion of said acoustic energy downstream and a second portion of said acoustic energy upstream; b. directional means disposed adjacent said transducers for effecting the passage of said acoustic energy along the shortest path and through the column of said fluids in said borehole therebetween; c. attenuation means also disposed adjacent said transducer for attenuating acoustic energy passing outwardly into said formation; said attenuation means and said directional means cooperating to discriminate the acoustic energy passing through said column of fluid from that passing through said formation; d. function-generating and -transmitting means for generating a function related to the acoustic energy received at the respective transducer serving as receiver and for transmitting said function to surface equipment; e. surface equipment for discriminating intelligence information from said function; f. supporting and conducting means connecting said down-hole tool with said surface equipment; g. depth-measuring means in association with said supporting and conducting means for determining the depth of said down-hole tool; and h. means for correlating said intelligence information with respect to said depth.

Claim 7

Apparatus for measuring flow velocity and density of fluids in a borehole penetrating subterranean formations comprising: a. down-hole tool having a plurality of transducers adapted for directionally transmitting and receiving acoustic energy primarily through said fluids therebetween, and for transmitting a first portion of said acoustic energy downstream and a second portion of said acoustic energy upstream; b. directional means disposed adjacent said transducers for effecting the passage of said acoustic energy along the shortest path and through the column of said fluids in said borehole therebetween; c. attenuation means also disposed adjacent said transducer for attenuating acoustic energy passing outwardly into said formation; said attenuation means and said directional means cooperating to discriminate the acoustic energy passing through said column of fluid from that passing through said formation; d. function-generating and -transmitting means for generating a function related to the acoustic energy received at the respective transducer serving as receiver and for transmitting said function to surface equipment; e. surface equipment for discriminating intelligence information from said function; f. supporting and conducting means connecting said down-hole tool with said surface equipment; g. depth-measuring means in association with said supporting and conducting means for determining the depth of said down-hole tool; and h. means for correlating said intelligence information with respect to said depth.

Claim 8

The apparatus of claim 5 wherein said down-hole tool has a transmitting transducer and at least two receiver transducers, and a function-generating means connected with each of said receiver transducers.

Claim 9

The apparatus of claim 6 wherein said at least two receiver transducers are equally spaced above and below said transmitting transducer when said tool is in said borehole.

Claim 10

THe apparatus of claim 6 wherein said at least two receiver transducers are both on the same side of said transmitting transducer.

Claim 11

The apparatus of claim 8 wherein the two end transducers are operable in both the transmitting and receiving modes.

Claim 12

The apparatus of claim 5 wherein said down-hole tool has at least two transducers that are operable in both the receiving and transmitting mode and includes switch means for alternately and respectively operating said transducers in the receiving mode and in the transmitting mode.

Claim 13

The apparatus of claim 5 wherein said function-generating and -transmitting means generates a function representative of elapsed time between transmission of said acoustic energy by a transmitting transducer and receipt of said acoustic energy by a receiving transducer.

Claim 14

The apparatus of claim 11 wherein said function-generating and -transmitting means employs a monotonically varying function generator starting at the time of transmission of said acoustic energy and increasing the absolute value of said function until arrival of said acoustic energy at which time said function is sampled and its magnitude transmitted to said surface equipment.

Claim 15

The apparatus of claim 5 wherein said function-generating and -transmitting means converts said acoustic energy to electrical signal having representative frequency and amplitude and said signal is amplified and transmitted to said surface equipment.

Claim 16

The apparatus of claim 5 wherein said function-generating and -transmitting means converts said acoustic energy to electrical signal having representative frequency and amplitude and said electrical signal is sampled via a rectifier and information representing the magnitude of the rectified signal is transmitted to said surface equipment.

Claim 17

In a method of monitoring fluids and flow in a borehole penetrating subterranean formations including the steps of emplacing a plurality of acoustic transducers that are spaced apart longitudinally of said borehole and in a down-hole tool at at least one location in said borehole, transmitting and receiving acoustic energy between said acoustic transducers, generating functions that are related to the transmitted and received acoustic energy, transmitting the functions to equipment at the surface for meaningful observations and for preserving a record if desired, the improvement comprising: a. transmitting acoustic energy of a predetermined frequency through said fluids in said borehole between said transducers, said acoustic energy having a first portion traveling along the longitudinal axis of said borehole and downstream, and a second portion traveling along the longitudinal axis of said borehole and upstream; b. discriminating said first and second portions of acoustic energy arriving through the fluid column in said borehole; and c. determining from said first and second portions of acoustic energy arriving at the respective transducer operating as a receiver the travel time downstream and the travel time upstream; the difference in the respective travel times upstream and downstream which is related to the fluid flow velocity; and the average travel time of the respective travel times upstream and downstream which is related to fluid density.

Claim 18

In a method of monitoring fluids and flow in a borehole penetrating subterranean formations including the steps of emplacing a plurality of acoustic transducers that are spaced apart longitudinally of said borehole and in a down-hole tool at at least one location in said borehole, transmitting and receiving acoustic energy between said acoustic transducers, generating functions that are related to the transmitted and received acoustic energy, transmitting the functions to equipment at the surface for meaningful observations and for preserving a record if desired, the improvement comprising: a. transmitting acoustic energy of a predetermined frequency through said fluids in said borehole between said transducers, said acoustic energy having a first portion traveling along the longitudinal axis of said borehole and downstream, and a second portion traveling along the longitudinal axis of said borehole and upstream; b. discriminating said first and second portions of acoustic energy arriving through the fluid column in said borehole; and c. determining from said first and second portions of acoustic energy arriving at the respective transducer operating as a receiver the travel time downstream and the travel time upstream; the difference in the respective travel times upstream and downstream which is related to the fluid flow velocity; and the average travel time of the respective travel times upstream and downstream which is related to fluid density.

Claim 19

The method of claim 15 wherein the travel time downstream and the travel time upstream, the difference in the respective travel times and the average travel time of the respective travel times are recorded in appropriate form with respect to depth.