Patent Application
20150136385
1. Field of Invention
The present disclosure relates in general to a system for use in imaging a subterranean borehole. More specifically, the present disclosure relates to a downhole imaging system having sensors, and with wiping elements for clearing any detritus that accumulates on the sensors.
2. Description of Prior Art
Geological data concerning subterranean formations is often gathered with an imaging technique. The data obtained usually relates to formation resistivity, formation porosity and/or permeability, identification of formation strata and the like. Zones of entrained hydrocarbons and reservoir production capabilities can be determined using this data. Often, the imaging is obtained with a downhole logging tool, which is deployed into a well that extends into the subterranean formation. Example downhole tools for imaging include resistivity tools, nuclear magnetic resonance (NMR) devices, and acoustic sensors. Resistivity tools usually include electrodes on one portion of the tool that are energized to emit a current into the formation, which is measured with sensors on another part of the tool. NMR devices release radiation that scatters from the formation, which is analyzed for assessing formation details. Similar to radiation devices, acoustic devices analyze acoustic data that reflects from the formation. The effectiveness of downhole sensors can be reduced when drilling mud or other material forms deposits on the surfaces of these sensors.
Disclosed herein is an example of a tool for imaging in a subterranean wellbore, that in an embodiment includes a housing, a sensor coupled with the housing that is in selective electrical communication with a formation intersected by the wellbore, and a wiper system having a wiper blade for selectively clearing a foreign substance from a surface of the sensor. The wiper system may further have a wiper rod that selectively reciprocates in a direction substantially parallel with an axis of the housing, and wherein the wiper blade is mounted in a wiper arm that is transversely coupled to the wiper rod. In this example, the wiper system further includes a motor selectively moving the wiper blade across the surface of the sensor. The sensor can be a planar electrode set or circular electrode set. In another example, the wiper blade is helically shaped and rotatable about the housing, so that when fluid flows axially past the housing, the fluid exerts a rotational force onto the wiper blade thereby causing the wiper blade to wipe across the surface of the sensor along a circular path. In this embodiment, opposing ends of the wiper blade are coupled with supports that rotate in a plane transverse to an axis of the housing. A transducer for creating an electrical field in and adjacent the wellbore can be included with the tool.
Another example of a tool for imaging in a subterranean wellbore includes a housing, sensors coupled with the housing having a surface in communication with fluid in the wellbore, and a pliable wiper blade selectively moveable across the surface and in contact with the surface so that the blade removes matter from the wellbore that adheres to the surface. The wiper blade may include polyether-ether-ketone and may also optionally be attached to a wiper arm for holding the wiper blade. Optionally included is a wiper assembly for reciprocating the wiper blade along a path substantially parallel with an axis of the housing. In an example, further included is a frame with a helical shaped arm in which the wiper blade is mounted and members coupled on opposing ends of the arm that rotationally mount the frame to the housing and so that when a fluid in the wellbore flows past the frame, a rotational force rotates the helical shaped arm and causes the wiper blade to sweep across the surfaces of the sensors.
Some of the features and benefits of the present invention having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which:
While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims.
The method and system of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. The method and system of the present disclosure may be in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout.
It is to be further understood that the scope of the present disclosure is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation.
Referring now to
The present invention described herein, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While a presently preferred embodiment of the invention has been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the present invention disclosed herein and the scope of the appended claims.
