When exploring for or extracting subterranean resources, such as oil, gas, or geothermal energy, and in similar endeavors, it is common to form boreholes in the earth. Such boreholes may be formed by engaging the earth with a rotating drill bit capable of degrading tough earthen materials. As rotation continues the borehole may elongate and the drill bit may be fed into it on the end of a drill string.
At times it may be desirable to alter a direction of travel of the drill bit as it is forming a borehole. This may be to steer toward valuable resources or away from obstacles. A variety of techniques have been developed to accomplish such steering. One such technique comprises pushing off an interior wall of a borehole with a radially extendable pad. This pushing may urge the drill bit laterally into the interior wall opposite from the pad. Extension of the pad may be timed in coordination with rotation of the drill bit to effect consistent steering.
Another steering technique comprises giving a borehole a cross-sectional shape that urges the drill bit in a lateral direction. For example, a cross-sectional shape comprising two circular arcs, one larger than the drill bit and one smaller, may urge the drill bit away from the smaller circular arc and into the open space provided by the larger circular arc. Such a cross-sectional shape may be formed by a radially extendable cutting element that may degrade an interior wall of a borehole when extended, to form a larger circular arc. As with an extendable pad, extension of an extendable cutting element may be timed in coordination with drill bit rotation to form a consistent borehole shape.
While these techniques have proven sufficient for their intended purposes, systems achieving greater steering while expending less energy and prolonging a useful life of a tool would be desirable.
A drill bit may be rotated to form a borehole through the earth. Such a drill bit may comprise fixed cutting elements, capable of degrading subterranean materials, protruding from an exterior of a body. These fixed cutting elements may be spaced at a constant radius from a rotational axis of the body to form an initially cylindrical borehole.
The body may also comprise at least one rotatable cutting element protruding from its exterior. To remove earthen material from an internal wall of the borehole, the rotatable cutting element may be positioned in a first rotational orientation wherein it may extend radially beyond the constant radius of the fixed cutting elements. To stop removing material from the borehole wall, the rotatable cutting element may be positioned in a second rotational orientation wherein it may remain radially within the constant radius.
Rotation of the rotatable cutting element may be synchronized with rotation of the drill bit to provide consistent removal in certain angular sections of the borehole. By altering material removal in these angular sections various borehole cross-sectional shapes may be formed. Specifically, a borehole may be provided with a smaller internal radius at some angular positions that may urge the drill bit laterally into other angular positions comprising a larger internal radius to steer the drill bit.
Referring now to the figures,
Each of these blades 223 may comprise a leading edge with a plurality of fixed cutting elements 224 protruding therefrom. Each of these fixed cutting elements 224 may comprise a portion of superhard material (i.e. material comprising a Vickers hardness test number exceeding 40 gigapascals) secured to a substrate. The substrate may be formed of a material capable of firm attachment to the body 220. As the drill bit 210 is rotated, the superhard material of each fixed cutting element 224 may engage and degrade tough earthen matter. Each of the fixed cutting elements 224 may be spaced at a constant radius relative to the axis 221 of the body 220 to create an initially cylindrical borehole.
In addition to the fixed cutting elements 224, a rotatable cutting element 225 may also protrude from an exterior of the body 220. This rotatable cutting element 225 may also comprise a portion of superhard material secured to a substrate, similar in some respects to the fixed cutting elements 224. An exposed surface of the rotatable cutting element 225 may comprise a three-dimensional geometry incorporating some of this superhard material. Based on its rotational orientation, this exposed geometry may engage an internal wall of the borehole and remove earthen matter therefrom. Removing this material may change an internal radius of the borehole in some areas. The amount of earthen matter removed may be altered by rotation of the rotatable cutting element 225 relative to the body 220.
A rotatable cutting element 325-1 may also protrude from an exterior surface of the drill bit 310-1 in relative proximity to the gauge cutting element 334-1. In contrast to the fixed cutting elements 324-1, this rotatable cutting element 325-1 may be capable of rotation, relative to the drill bit 310-1, about its own axis 331-1. An exposed portion of this rotatable cutting element 325-1 may comprise a three-dimensional geometry comprising an offset distal end 332-1. This exposed geometry may also comprise a slanting surface 333-1 that may stretch from the offset distal end 332-1 toward a proximal base thereof.
The unique aspects of this three-dimensional exposed geometry may allow it to extend radially beyond the initial radius 330-1 in a first rotational orientation as shown. In this first rotational orientation, the slanting surface 333-1 may be positioned in a generally parallel alignment with a leading face of the gauge cutting element 334-1. It is believed that such an alignment may, in some subterranean formations, lead to a smoother extension of the offset distal end 332-1. Also, in this first rotational orientation, the slanting surface 333-1 may be positioned in a generally normal alignment relative to the initial radius 330-1.
When extended in this manner, the offset distal end 332-1 may cut an extended radius 335-1 into the borehole by removing additional earthen matter from an internal wall of the borehole. Removing material from this internal wall may change an internal radius of the borehole, at least in an angular section thereof. This extended radius 335-1 may be restricted to certain angular sections positioned about a circumference of the borehole via deliberate rotational control of the rotatable cutting element 325-1 to create purposefully non-cylindrical cross-sectional shapes.
If extension and retraction of the rotatable cutting element 325-2 is performed in unison with rotation of the drill bit 310-2, such that a given rotational orientation of the drill bit 310-2 correlates with a set rotational orientation of the rotatable cutting element 325-2, then a consistent borehole cross-sectional shape may be created. Various embodiments of such unison rotation may comprise spinning the rotatable cutting element 325-2 in consecutive full turns or oscillating it back and forth. In addition, or alternatively, extension and retraction of the rotatable cutting element 325-2 may be performed at higher frequencies to reduce likelihood of the drill bit 310-2 sticking to the borehole wall.
In a first rotational orientation of the rotatable cutting element 425-1, as shown in
This torque-generating apparatus 550-1, 550-2 may be connected to the rotatable cutting element 525-1, 525-2 via a set of gears. In the embodiment shown, the torque-generating apparatus 550-1, 550-2 comprises an axially-translatable rack gear 551-1, 551-2. Teeth of this rack gear 551-1, 551-2 may mesh with those of a pinion gear 552-1, 552-2 attached to the rotatable cutting element 525-1, 525-2. Thus, as the rack gear 551-1, 551-2 translates, the pinion gear 552-1, 552-2 may rotate the rotatable cutting element 525-1, 525-2. Specifically, as shown in
The rotatable cutting element 725-1, shown in
Whereas this discussion has referred to the drawings attached hereto, it should be understood that other and further modifications apart from those shown or suggested herein, may be made within the scope and spirit of the present disclosure.
Number | Name | Date | Kind |
---|---|---|---|
4222446 | Vasek | Sep 1980 | A |
4511006 | Grainger | Apr 1985 | A |
4553615 | Grainger | Nov 1985 | A |
4690228 | Voelz et al. | Sep 1987 | A |
4690229 | Raney | Sep 1987 | A |
4751972 | Jones et al. | Jun 1988 | A |
6142250 | Griffin | Nov 2000 | A |
7604073 | Cooley et al. | Oct 2009 | B2 |
7703559 | Shen et al. | Apr 2010 | B2 |
7845436 | Cooley et al. | Dec 2010 | B2 |
7849936 | Hutton | Dec 2010 | B2 |
7987931 | Cooley et al. | Aug 2011 | B2 |
8087479 | Kulkarni | Jan 2012 | B2 |
8141657 | Hutton | Mar 2012 | B2 |
8202335 | Cooley et al. | Jun 2012 | B2 |
8353974 | Cooley et al. | Jan 2013 | B2 |
8561728 | Cooley et al. | Oct 2013 | B2 |
8763726 | Johnson | Jul 2014 | B2 |
8931582 | Cooley et al. | Jan 2015 | B2 |
8950516 | Newman | Feb 2015 | B2 |
9382762 | Cooley et al. | Jul 2016 | B2 |
9920579 | Newman | Mar 2018 | B2 |
10100584 | Schroder et al. | Oct 2018 | B1 |
10577917 | Marshall | Mar 2020 | B2 |
10633923 | Downton | Apr 2020 | B2 |
10669786 | Marshall | Jun 2020 | B2 |
10837234 | Marshall | Nov 2020 | B2 |
20130292185 | Knull | Nov 2013 | A1 |
20170204677 | Yu | Jul 2017 | A1 |
20200270950 | Hall | Aug 2020 | A1 |
Number | Date | Country | |
---|---|---|---|
20200270950 A1 | Aug 2020 | US |