US2117522A - Apparatus for orienting drilling tools - Google Patents

Description

May 17, 1938. A. e. H. STRAATMAN APPARATUS FOR ORIENTING DRILLING TOOLS Filed May 19, ,1937

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fllphons Gerard Hubert fizfaaz man. By His Attorney; flandXkufl Patented May 17, 1938 Alphons Gerard Hubert Straatm an, The Hague, Netherlands, assignmto Shell Development Company, San Francisco, Calif., a corporation of Delaware- Application May 19, 1937, Serial No. 143,575 In the Netherlands May 22, 1936 4 Claims.

This invention relates to a method and apparatus for orienting various tools and devices adapted to be lowered into a borehole on a string of tubing or pipe, such as deflecting wedges, whipstocks, knuckle 'joints, impression blocks, inclinometers, etc.

When orienting in a borehole any drilling tool of the above character, for example, a whipstock, the following procedure is commonly followed:

After securely attaching the drilling tool (whipstock) to the first (lowermost) pipe stand, suspended in the derrick, the drilling tool is given a known position in azimuth, which is considered as zero position. v

The pipe stand and the whipstock are then lowered into the borehole, and the amount of rotation occurring with regard to said zero azimuth position is determined every time another pipe stand is added to the string.

For this purpose, it is customary to clamp to the upper portion of every pipe stand being added to the string a special device comprising two members: a stationary member rigidly attached to the pipe, and a rotatable member carrying a sighting device. One of these members is usually. provided with a scale, and the other with an index, so that the amount of their rotation with.

, upper portion of the pipe stand is in the position formerly occupied by its lower portion. The

amount and direction of the rotation of the pipe and of the drilling tool attached thereto occurring during this process can then be measured by turning the rotatable member untilthe sighting device is again trained on the reference point. After recording the rotational displacement of the pipe, both members are removed from the pipe and attached to the top of the next pipe section being added to the string and the operation is repeated. In order to minimize the loss of time,

two orienting devices, each comprising a stationary and a rotatable member are commonly used in such operations. V

According to a modification of this method, the pipe string is returned to its original directional position (zero azimuth) after lowering each consecutive pipe section by turning the string until the sighting device is again in alignment with the chosen plane of direction. This method is however relatively inaccurate and causes considerable delays owing to the dlmculty of eflecting repeated rotational adjustments of the pipe string.

Both these methods have moreover the disadvantage that a reading has to be taken and recorded after each consecutive pipe stand has been added to the string and lowered into the borehole. This not only causes delay, but, because of the large number of readings required, results in ure the separate consecutive rotational displacements of a. pipe string without the necessity of recording said measurements, and, second, to obtain automatically the algebraic summation of said separate displacements in order to obtain the total rotational displacement of a pipe string, only a single reading being necessary after the final measurement. This total rotational displacement may be determined with regard .to either a known initial position, or with regard to a position to be determined, and the present orientation method may therefore be used either when lowering the pipe string (for example, in placing a whipstock), or whenraising the pipe string (for example, in'withdrawing an inclinometer or a core orienting device). It is obvious that in such cases changes in the sequence of steps described hereinbelow may be made without departing from the spirit of the invention.

If, in order to save time, more than one orienting device is used, as described below, the readings of the individual instruments will, of course, have to be added up algebraically as the last step of the process.

The present method and orienting device will be better understood from the following description, taken with reference to the attached drawing, wherein:

Fig. 1 is a plan view of the present orienting device, and Fig. 2, a cross-sectional elevation view of the same device.

Referring to Fig. 1, the drawing shows a clamp-- of the measuring device in a direction parallel to that of the pipe, and with a handle I.

The measuring device comprises the following parts, shown in both Fig. 1 and Fig. 2:

(1) A sighting or aligning member 8, such, for example, as a telescope;

(2) A rotatable graduated scale member, such as a plate or ring ill, to which the telescope is connected in fixed relationship by means of a supporting member or fork 9; 1 g

(3) A rotatable index member, such as ring I], concentric with and rotatable with regard to said plate I0, and provided with an index mark which slides along the scale of plate I when said plate and the ring I l rotate with regard to each other.

The scale plate Ill and the index ring H can be locked in fixed relationship to each other by tightening the upper clamp screw I2 (shown in Fig. 1), which forces a friction ring I3 against a second friction ring l4, connected to index ring H, as shown in Fig. 2.

In turn, the index ring H is rotatable in the base l5, and can be locked in fixed relationship thereto by tightening a lower clamp screw [6, The base I5 is secured to the tabular part 'l'l of the clamping member I by means of screws 2! and 22.

The telescope 8 comprises an objective l8 forming an image in the front plane of an ocular I9 with engraved cross lines, and can be adjusted by means of a knob 20 at the base of the instrument. This ocular has the advantage that the image can be observed at the normal visual distance without the eye being brought quite near the glass. The telescope is pivotally supported to allow for motion of its axis in a vertical plane up to inclinations of about 30 or more both upwards and downwards.

In practicing the method of the present invention the following procedure may be followed when using, for example, two devices of the type described above:

The tool to be oriented is attached to the lower end of the first pipe stand, and is suspended over the borehole in a chosen position. For example, a whipstock or a knuckle joint may be suspended so as to have its plane of symmetry in the'direction it should have at the bottom of the bore-hole.

The indexmark of the index ring H of each measuring device is placed opposite the zero mark of the scale l0, and one of the devices is clamped to the top portion of the first pipe section. By loosening the lower clamp screw I6,

the index ring H is released with regard to the base l5, but remains locked with regard to the scale In and to the telescope 8 connected therewith.

knob 20 until the line of sight is trained on a distant object, for example, a ranging pole, both the scale In and the index ring ll rotating together with the telescope. After'this alignment, the index ring is locked again by tightening the clamp screw I6. I

The first pipe section with the device attached thereto is then lowered into the borehole until said device is near the derrick fioor. Another pipe stand is then added and the string suspended in the elevator, a certain amount of rotation unavoidably occurring during this operation, and the device rotating together with the string.

The upper clamp screw l2 of the orienting device -is then loosened, the scale it being thereby released with regard to the index ring M, the

ll again rotating with the telescope.

provided with steel jaws 6 for adjusting the axislatter, however. remaining locked in relation to the base IS. The telescope 8, together with the scale I0, is then rotated with regard to the index ring II by an amount equal and opposite to the rotational displacement of the string during the lowering thereof, until it is again trained on the ranging pole. By tightening again the clamp screw l2 the rotation which has occurred is automatically registered as the displacement between the mark zero on the scale 10 and the index mark on index ring II, and the new setting of the orienting device may serve as the initial one for the next measurement.

Meanwhile, the operator at the top of' the derrick attaches a second orienting device to the top portion ofthe second stand. The lower clamp screw I6 is released and the telescope trained on the ranging pole, the scale l0 and the indexring After the clamp screw [8 has been tightened again, the first orienting device below may be removed from the pipe, and the string lowered throughout the length of the second stand. In this manner, the operator on the floor of the derrick manipulates only the upper clamp screw i2, and the operator at the top of the derrick only the lower clamp scre'w IS, the possibility of errors being thereby minimized.

. This, cycle of operations is repeated until the whole string has been run in. The total rotational displacement of the tool attached to the lower end of the string is then obtained by taking the algebraic sum of the final readings obtained on each device separately at the end of the'whole series of operations. The orientation of the tool at the lower end of the pipe string is then effected as fol- I lows:

is, the device is given its original setting. The

clamp screw l'6 is then released, and the telescope is -rotated together with the scale In and the inindex mark on the index ring indicates on the scale the total rotational displacement, that is, the

scope is again trained on the ranging pole, the

whipstock or other drilling tool being thereby brought into the desired position. The telescope 8 is then rotated by means of It is, of course, obvious that a drilling tool can be oriented by the present method while using only one orienting device, although such operation consumes a somewhat longer time.

In such case, the operations are carried out as follows:

The orienting device is attached to thetop of the first pipe stand, and the telescope is trained on the ranging pole with the index mark on ring I l in register with the zero mark on the scale Hi. All clamp screws are then tightened and the pipe stand lowered until the orienting device is near the fioor of the derrick. The telescope is then' I device removed from the pipe, and hoisted on a cable to the top of the derrick, where it is attached to the top of the second pipe stand. The telescope is then trained on the ranging pole by releasing clamp screw IS, the index ring ll remaining at the same setting with regard to scale H) as it was after the sighting operation at the floor of the derrick. The second stand is then lowered into the borehole, and the cycle of operations repeated until the whole string has been run in and the top of the last pipe stand is near the floor of the derrick, the displacement of the index mark on the ring I I with regard to the zero mark on scale I automatically giving the algebraic summation of the rotational displacements of the string occurring as each pipe stand is lowered. The clamp screw I 2 is then released, and the telescope rotated together with the scale I0 until the zero mark on the latter registers with the index mark on index ring II. The clamp screw I2 is then tightened again and the tubing string is rotated together with the orienting device until the telescope is in alignment with the ranging pole, whereby the tool at the end of the pipe string is given its desired position.

It is, of course, understood that the orienting method comprising the steps of returning the pipe string to its original oriented position by rotating it after the addition of each separate pipe stand can equally well be carried out by means of the present device.

I claim as my invention:

1. In apparatus for determining the orientation of a tool supported by a pipe string for longitudinal motion within a borehole, an orienting device adapted to be rigidly clamped to the pipe, comprising a first member rotatable with regard to said device, a second member rotatable with regard to said device and to said first member, and means for positioning said rotatable members in known relationship to a desired orientation plane, said rotatable members cooperating with each other to indicate the extent and direction of rotation of the pipe during the longitudinal motion of the pipe within a borehole.

2. In apparatus for determining the orientation of a tool supportedby a pipe string for longitudinal motion within a borehole, an orienting device adapted to be rigidly clamped to the pipe, comprising a first member rotatable with regard to said device, a second member rotatable with regard to said device and to said first member, means for positioning said rotatable members in known relationship to a desired orientation plane, means for locking said first member with said second member, means for locking said second member with the device, said members cooperating with each other to indicate the extent and direction of rotation of the pipe with regard to the desired orientation plane during the longitudinal motion of the pipe within the borehole.

3. An orienting device for determining the orientation of a pipe string within a borehole, comprising a body member adapted to be rigidly clamped to the pipe, a scale member rotatably held by said body member, a sighting member supported in fixed directional relationship in a hori-- zontal plane by said scale member, an index member rotatably held by said body member, said scale member and said index member being rotatable with regard to each other, means for locking the scale member with the index member, means for locking the index member with the body member, said index member cooperating with said scale member to indicate the extent and direction of rotation of the pipe with regard to the desired orientation plane during the longitudinal motion of the pipe within the borehole.

4. In the apparatus of claim 3, a sighting device mounted on the scale member for pivotal axial motion in a vertical plane.

ALPHONS GERARD HUBERT STRAATMAN.

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