DOWNHOLE IMAGING SYSTEMS, DOWNHOLE ASSEMBLIES, AND RELATED METHODS
A downhole imaging system comprises an imaging device operably coupled to a drill string and configured to generate an image of a subterranean formation from within a wellbore. The downhole imaging system comprises a processor operably coupled to the imaging device. The imaging device includes a sensor comprising a transmitter and a receiver, and a coding mask located between the sensor and the subterranean formation. Downhole assemblies including such devices and methods of generating an image of a subterranean formation in a wellbore are also disclosed.
1 . A downhole imaging system, comprising:
an imaging device operably coupled to a drill string and configured to generate an image of a subterranean formation from within a wellbore, the imaging device comprising:
a sensor comprising a transmitter and a receiver; and
a coding mask located between the sensor and the subterranean formation; and
a processor operably coupled to the imaging device.
2 . The downhole imaging system of claim 1 , wherein the transmitter is a piezoelectric transmitter configured to generate an acoustic signal that passes through the coding mask.
3 . The downhole imaging system of claim 1 , wherein the transmitter and the receiver of the sensor are the same device.
4 . The downhole imaging system of claim 1 , wherein the transmitter is configured to transmit a signal and the receiver is configured to receive a signal, and wherein the sensor is configured to pass each of a transmitted signal and a received signal through the coding mask.
5 . The downhole imaging system of claim 1 , wherein the coding mask comprises multiple thicknesses.
6 . The downhole imaging system of claim 5 , wherein the multiple thicknesses of the coding mask vary randomly.
7 . The downhole imaging system of claim 1 , wherein the coding mask comprises or is at least partially covered with a polymer material.
8 . The downhole imaging system of claim 1 , wherein the processor is configured to generate the image without using depth information of the imaging device within the wellbore.
9 . The downhole imaging system of claim 1 , wherein the processor is configured to generate the image using compressive sensing.
10 . The downhole imaging system of claim 1 , wherein the processor generates the image from at least two individual images using a mathematical algorithm, and wherein the at least two individual images at least partially overlap one another.
11 . The downhole imaging system of claim 1 , wherein the sensor is configured to receive at least one of an optical signal, a resistivity signal, an x-ray signal, a gamma signal, an electric signal, a magnetic signal, a neutron signal, a nuclear magnetic resonance signal, or a thermal signal.
12 . The downhole imaging system of claim 1 , wherein the coding mask is configured to rotate relative to the sensor.
13 . A downhole assembly, comprising:
at least a portion of a drill string;
a sensor coupled to a component of the at least a portion of the drill string, the sensor being located and configured to transmit and receive signals between the sensor and a subterranean formation from within a wellbore;
a coding mask comprising a volume of material having a varying thickness, the coding mask configured to provide a compressed measurement of individual data points obtained from the signals transmitted and received with the sensor; and
a processor operably coupled to the sensor, the processor configured to compile an image of the subterranean formation based on the compressed measurement of the individual data points.
14 . A method of generating an image of a subterranean formation in a wellbore, comprising:
conveying a bottom-hole assembly in the wellbore, the bottom-hole assembly comprising an imaging device including a sensor comprising a transmitter and a receiver;
moving the sensor in the wellbore;
transmitting a wave using the transmitter;
receiving a first individual image and a second individual image using the receiver, the second individual image comprising an overlap region with the first individual image; and
generating the image using a mathematical algorithm, the first individual image, the second individual image, and the overlap region,
wherein transmitting the wave comprises breaking a phase uniformity of the transmitted wave.
15 . The method of claim 14 , wherein breaking the phase uniformity of the transmitted wave includes locating a coding mask between the sensor and the subterranean formation.
16 . The method of claim 14 , wherein transmitting the wave comprises transmitting an acoustic wave.
17 . The method of claim 14 , wherein generating the image using the mathematical algorithm comprises using a stitching algorithm.
18 . The method of claim 14 , wherein receiving the first individual image and the second individual image comprises using compressive sensing.
19 . The method of claim 18 , further comprising calibrating the compressive sensing using one of a known image data and a sample.
20 . The method of claim 14 , wherein moving the sensor comprises rotating the imaging device in the wellbore.
21 . The method of claim 14 , wherein generating the image is performed in the wellbore without using a depth of the imaging device in the wellbore.
22 . The method of claim 14 , further comprising altering drilling parameters based on information obtained from the image of the subterranean formation during a drilling or reaming operation.