Drill steering apparatus

An improved well drilling steering tool including a tubular body, an upper stabilizer mounted on the tubular body with a means contained therein for sensing the low side of the well bore and for transmitting hydraulic signals responsive thereto, valving means connected in the tubular body to control the end location for the hydraulic signals from the sensing means, a lower stabilizer mounted on the tubular body close to the drill bit and having means for exerting a transverse thrust to the tubular body responsive to the hydraulic signals received from the sensing means and the valving means, the upper and lower stabilizers are supported on the tubular body by upper and lower floating rings and retaining rings which cause the stabilizers to rotate with the tubular body and allow relative radial movement between the stabilizers and the tubular body and the stabilizers and their mounting rings include passages therebetween to prevent the build-up of materials within the stabilizers which would interfere with their operation.

BACKGROUND 
The drill steering apparatus similar to the present invention is disclosed 
in my prior U.S. Pat. No. 4,394,881. In such apparatus, stabilizer rings 
are mounted by retaining rings on the drill string one being immediately 
above the drill bit and another being spaced thereabove on the drill 
string. In each stabilizer ring are pistons, the upper of which has 
pistons which sense the low side of the well bore and the lower of which 
has pistons which exert a preselected force on the drill string responsive 
to the sensing of the low side of the well bore by the upper pistons. In 
this manner, the apparatus creates side thrusts on the drill bit which 
cause it to proceed in the well bore in the desired direction. 
In the use of this apparatus, difficulty has been encountered in that the 
tool rotated within the stabilizer rings so that the stabilizers could not 
be rotated to ensure that the stabilizer rings could pass easily through 
tight spots and ledges which are prevalent in a well bore. Additionally, 
the retaining rings positioned above and below each of the stabilizer 
rings rotated with the drill string and their engagement of the ends of 
the stabilizer body creates sufficient heat to cause a failure of seals at 
the surface of the body ends and the retaining rings. 
In the past stabilizers have long been used in the drilling of well bores 
to support the drill collars in directional drilling to control the angle 
of drilling. Such drill collars were tightly secured to the drill collar. 
Examples of such stabilizers are shown in U.S. Pat. Nos. 4,011,918 and 
4,275,935. 
In order to resolve the problem encountered by the stabilizer rings of the 
drill steering tool in moving through tight spots, the rotation of the 
drill string or tool body through the stabilizer ring had to be avoided so 
that the stabilizer ring could be rotated. 
Another disadvantage of the prior steering tool was the accumulation of 
solids material between the stabilizer rings and the steering body which 
interfered with the operation of the steering apparatus. 
SUMMARY 
The present invention relates to an improved drill steering tool which 
relies on master sensing pistons which sense the low side of the well bore 
and slave pistons positioned close to the drill bit which respond to the 
sensed position by the master pistons and the preselected relationship 
between the two sets of pistons to control the side thrusts on the drill 
bit. The improved stabilizer rings include a ring body with outward 
projecting ribs or blades, internal pistons, and end slots in the ring 
body at each end, floating rings having projecting end lugs on one end of 
the ring for engaging within the end slots of the stabilizer ring body and 
slots on the other end of the floating ring which are ninety degrees apart 
from the end lugs, and retaining rings having end lugs projecting from one 
end for engagement in the slots of the adjacent floating ring, internal 
slots within the retaining rings and means for securing the retaining 
rings to the steering body. Each of the stabilizer rings is provided with 
a ring body between two floating rings with a retaining ring engaging each 
of the floating rings and secured to the steering body. 
An object of the present invention is to provide an improved drill steering 
tool with stabilizer rings which are readily moved through tight spots and 
past ledges in the well bore. 
Another object is to provide an improved drill steering apparatus with 
stabilizer rings which rotate with the body of the drill steering tool 
without sacrificing the action of the steering tool. 
Still another object is to provide an improved drill steering apparatus 
having stabilizer rings in which packing off well material is not a 
problem.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The improved steering tool 10 is similar to the tool shown in my 
aforementioned U.S. Pat. No. 4,394,881 with the exception that the upper 
and lower stabilizers have been replaced by improved upper stabilizer 12 
and improved lower stabilizer 14. Steering tool 10 is shown positioned 
within well bore 16 with drill bit 18 on the lower end of steering tool 10 
with the upper end of steering tool 10 being connected to drill string 20. 
The purpose of steering tool 10 is to control the direction of drilling of 
well bore 16, both as to direction and inclination. As is fully explained 
in my prior patent, this control is achieved through the use of 
stabilizers, the upper of which senses the low side of well bore 16 and 
transmits pressure to the lower stabilizer to cause it to exert a force on 
drill bit 18 to cause it to move in the direction in which it is desired 
that well bore 16 proceed. As previously mentioned, the prior steering 
tool had difficulty moving through tight spots in the well bore since the 
stabilizers did not rotate with the tool body and also mud and other 
materials in the well tended to collect in the annulus between the tool 
body and stabilizer ring I.D. preventing radial movement of the stabilizer 
rings. 
The improved structure of the present invention avoids these difficulties 
with the new design of stabilizers 12 and 14. Each of stabilizers 12 and 
14 is secured to rotate with body 22 of steering tool 10. Also, provision 
is made to clear the interior of the stabilizers so that materials in the 
well bore flow readily therethrough and are not trapped therein to 
interfere with the operations of the sensing pistons and the slave 
pistons. 
Upper stabilizer 12, as shown in FIGS. 2 and 3, includes tubular body 24 
having blades 26 extending longitudinally along its outer surface. Inner 
surface 30 of body 24 is spaced from the exterior surface 29 of body 22 
and is recessed at 30 to receive sensing pistons 32 which are mounted in 
body 22 as shown. As can be seen from the drawings, there are four sensing 
pistons 32 in engagement with inner surface 28 of body 24 which include 
two pairs of opposed, axially spaced pistons 32. Tubular body 24 is 
secured to tool body 22 by upper and lower floating rings 34 and retaining 
rings 36. As first seen in FIG. 7, floating rings 34 have opposed 
projections 38 which engage within slots 40 in the ends of tubular body 
24. Slots 42 in the opposite end of floating rings 34 from projections 38 
are positioned at right angles to the radial position of the projections 
38. Retaining rings 36 include projections 44 which engage within slots 42 
of the floating rings 34, radial bores 46 and internal axial slots 48. 
Interior surface 50 of retainer rings 36 fits closely with the exterior of 
body 22. Retainer rings 36 are secured to body 22 by pins 52 which extend 
through radial bores 46 into recesses 54 in body 22 and are locked into 
position by lock pins 56 which extend through ring 36 and pins 52. The 
interiors of floating ring 34 and tubular body 24 are substantially larger 
than the exterior of body 22 to allow smooth operation of steering tool 
10. 
Lower stabilizer 14, as shown in FIGS. 4 and 5 includes tubular body 58 
having blades 60 extending longitudinally along its outer surface. Inner 
surface 62 of body 58 is spaced from the exterior surface 29 of body 22 
and is recessed at 64 to receive actuating or slave pistons 66. As can be 
seen from the drawings, there are eight sensing pistons 66 in engagement 
with inner surface 64 of body 58 which include two upper and two lower 
pairs of opposed, axially spaced pistons 66. Tubular body 58 is secured to 
tool body 22 by upper and lower floating rings 34 and upper and lower 
retaining rings 36. As described above with reference to upper stabilizer 
12, the means supporting lower stabilizer 14 to tubular body 22 including 
rings 34 and 36 are identical in structure. Also, as shown in the 
drawings, pistons 32 and 66 include suitable sealing means to engage 
within the bores within which they are confined. Inserts 67 in body 22 is 
provided to the bores for receiving pistons which are axially aligned and 
to provide communication from the body passages to the pistons at the 
inner end of their bores. 
Hydraulic communication is supplied through body 22 and adjustable valving 
means 68, as shown in my prior patent and reference is made thereto for a 
description of such structure, its operation whereby the connections 
between upper stabilizer 12 and lower stabilizer 14 and the relationship 
and operation of the other elements of the steering tool. With such means 
the interconnection in the hydraulic passages between the sensing pistons 
32 and the actuating pistons 66 can be connected to cause drill bit 18 to 
be urged in the direction in which drilling of well bore 16 is desired to 
proceed. In this manner, well bore 16 can be brought back to vertical, or 
can be deviated at a specific angle to vertical and at a specific azimuth 
so that well bore 16 proceeds to a preselected location.