Measurement-while-drilling acoustic system employing multiple, segmented transmitters and receivers
First Claim
1. A measurement-while-drilling (MWD) tool for use during drilling of a wellbore having a longitudinal axis in a formation having a reflecting interface, comprising:
- (a) a tool body;
(b) a plurality of spaced apart transmitter arrays carried by the tool body, each said transmitter array containing a plurality of spaced apart transmitter elements circumferentially disposed about the tool body, each said transmitter element adapted to propagate acoustic energy into a formation surrounding the wellbore;
(c) at least one receiver axially spaced apart from the plurality of transmitter arrays on the tool body, said receiver detecting acoustic energy traveling through the formation in response to the acoustic energy transmitted by said transmitter elements; and
(d) a processor, said processor selectively activating a plurality of the transmitter elements to focus acoustic energy into the formation in a selected direction towards the reflecting interface and processing the responses of the receiver to determine a parameter of interest.
0 Assignments
0 Petitions
Accused Products
Abstract
This invention is directed toward apparatus and methods for obtaining acoustic measurements or "logs" of earth formations penetrated by a borehole. More particularly, the invention is directed toward obtaining the acoustic measurements while the borehole is being drilled. The downhole apparatus comprises a plurality of segmented transmitters and receivers which allows the transmitted acoustic energy to be directionally focused at an angle ranging from essentially 0 degrees to essentially 180 degrees with respect to the axis of the borehole. Downhole computational means and methods are used to process the full acoustic wave forms recorded by a plurality of receivers. A two way communication system is also used in the preferred embodiment of the invention.
267 Citations
24 Claims
-
1. A measurement-while-drilling (MWD) tool for use during drilling of a wellbore having a longitudinal axis in a formation having a reflecting interface, comprising:
-
(a) a tool body; (b) a plurality of spaced apart transmitter arrays carried by the tool body, each said transmitter array containing a plurality of spaced apart transmitter elements circumferentially disposed about the tool body, each said transmitter element adapted to propagate acoustic energy into a formation surrounding the wellbore; (c) at least one receiver axially spaced apart from the plurality of transmitter arrays on the tool body, said receiver detecting acoustic energy traveling through the formation in response to the acoustic energy transmitted by said transmitter elements; and (d) a processor, said processor selectively activating a plurality of the transmitter elements to focus acoustic energy into the formation in a selected direction towards the reflecting interface and processing the responses of the receiver to determine a parameter of interest. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
-
-
17. A method of determining a parameter of interest during drilling of a wellbore, comprising:
-
(a) conveying a measurement-while-drilling (MWD) tool in the wellbore, said MWD tool comprising a plurality of spaced apart acoustic transmitter arrays carried by a tool body, each of said plurality of transmitter arrays containing a plurality of spaced apart transmitter elements circumferentially disposed about the tool body, each said transmitter element adapted to propagate acoustic energy into a formation surrounding the wellbore; (b) activating the transmitter elements in said plurality of transmitter arrays in a preselected order in a manner that focuses acoustic energy into the formation in a selected direction; (c) detecting acoustic energy responsive to the transmitted energy and traveling through the formation by a receiver disposed spaced apart from said transmitter arrays and generating signals corresponding to the detected energy downhole; and (d) processing the generated signals downhole to compute a parameter of interest. - View Dependent Claims (18)
-
-
19. A measurement-while-drilling (MWD) tool for use during drilling of a wellbore, comprising:
-
(a) a tool body; (b) at least one acoustic transmitter carried by the tool body; (c) a plurality of axially spaced apart receiver arrays axially spaced apart from the at least one transmitter along the tool body, each of said plurality of receiver arrays containing a plurality of spaced apart receiver elements circumferentially disposed about the tool body, each said receiver element adapted to provide a signal indicative of acoustic energy traveling through the formation; and (d) a processor carried by the tool body, said processor activating the transmitter to propagate acoustic energy into the formation and processing signals from the receiver elements to focus energy from a selected direction to determine a parameter of interest. - View Dependent Claims (20, 21, 22)
-
-
23. A drilling system for drilling a wellbore, comprising:
-
(a) a rig; (b) a drill string having a tubing with a drill bit at a bottom end thereof for drilling the wellbore; (c) a bottom hole assembly uphole of the drill bit for determining a parameter of interest, said bottomhole assembly comprising; (i) a tool body; (ii) a plurality of acoustic transmitter arrays spaced axially along the tool body, each said transmitter array having a plurality of spaced apart transmitter elements circumferentially disposed about the tool body, each said transmitter element adapted to propagate acoustic energy into a formation surrounding the wellbore; and (iii) a receiver array axially disposed along the tool body spaced apart from the plurality of transmitter arrays, said receiver array having a plurality of spaced apart receiver elements circumferentially disposed about the tool body, each said receiver element providing signals in response to the acoustic energy received by such receiver element; (d) a downhole processor in the bottomhole assembly, said downhole processor processing signals from the receiver elements to focus signals indicative of received energy from a specified direction and determining the parameter of interest during drilling of the wellbore; and (e) a computer at the surface, said computer receiving data from the downhole processor and in response thereto generating command signals relating to the drilling of the wellbore.
-
-
24. A measurement-while-drilling (MWD) tool for use during drilling of a wellbore having a longitudinal axis in a formation having a reflecting interface, comprising:
-
(a) a tool body; (b) a plurality of spaced apart transmitter arrays carried by the tool body, each said transmitter array containing a plurality of spaced apart transmitter elements circumferentially disposed about the tool body, each said transmitter element adapted to propagate acoustic energy into a formation surrounding the wellbore; (c) at least one receiver axially spaced apart from the plurality of transmitter arrays on the tool body, said receiver detecting acoustic energy traveling through the formation in response to the acoustic energy transmitted by said transmitter elements; and (d) a processor, said processor selectively activating a plurality of the transmitter elements to with a known time delay between said elements to focus acoustic energy into the formation in a selected direction towards the reflecting interface and processing the responses of the receiver to determine a parameter of interest.
-
Specification