US2672050A - Apparatus for locating uncemented portions of well casings - Google Patents

Description

March 16, 1954 Filed March 8, 1950 B. w. SEWELL 2,672,050

APPARATUS FOR LOCATING UNCEMENTED PORTIONS OF WELL CASINGS 2 Sheets-Sheet 1 ben 55M611 {Sax/ember h5g1 0. 7 abhor nag March 16, 1954 B. SEWELL 2,672,050

APPARATUS F LOCATING UNCEMENTED L PORTIONS OF WELL CASINGS Filed March 8, 1950 2 Sheets-Sheet 2 P SI F51. us WW/WA 32 E I G '2 ban. CJTSecJeZZ Unverzbor' b k Qbtorneg Patented Mar. 16, 1954 i I APPARATUS FOR LOCATING UN 'CEMEN'I ED PORTIONS OF WELL CASINGS Ben W. Sewell, Tulsa, Okla; assignor to Standard Oil Development Company, a corporation of Delaware Application Marcus, 1950, Serial No. 1,413,289

4 Claims. 1

This invention relates to anapparatus for determining the successful crunsuccessful cementing of a casing in a well. The apparatus is primarily intended for application in oil wells. By means of this inventionfit is possible to determine What portions of a well casing are, or are not properly cemented in the well.

One of the most important problems in successfully producing oil, or gas from a well relates to the successful exclusion of water from the productive formations. Again, it is generally desirable, particularly in the case of deep wells, to protect the well casing from the tremendous collapsing pressure which may exist in the well. These and other desirable objectives are conventionally attained by cementing the casing in the well bore hole. It is apparent, however, that in order to successfully obtain the benefits of oil well cementing, it is necessary to know the extent to which cement has extended behind the casing, and to know to What portions of the easing cement has not extended. The present invention is directed to this specific objective; that is, to provide operators with information as to what portions of a well casing are properly cemented, or conversely what portions of the well casing are not properly cemented.

' The apparatus of this invention, to achieve this objective, applies an internal deforming force to the well casing. In the case in which the well casing is not cemented, the deforming force can cause the casing to assume an ellipti: cal, rather than a circular cross-section. However, in the case in which the well casing is properly cemented in the bore hole, the cement will provide sufficient lateral support to the well casing so that comparatively little or no deformation will occur on'application of the deforming force. l p

The apparatus of this invention by which the indicated method may be successfully conducted consists of two wheel like members adapted to roll along opposing sides of the interior of a well casing. At least one of these wheel like members is so controlled by a hydraulic force, that it can be forced away from the other of the wheel like members so thattogether the two members can exert a deforming force on the cas ing. The apparatus includes means for period? cally forcingat least one of thewheellikeiiienibers away rrom'fme other fo'f the members? and includes means" for measuring. tl'ie foroev thus applied, and means'for" measuringthefielative displacement. of the two wheel,likemempfii-s.. 'It isapparent that'knowin'g the fbrce aii pli e d as a mechanical deforming force to the casing, the relative displacement of the two wheel like mam: bers applying the force will indicate the deformation of the casing in response to this force. Thus, it is possible to tell when the casing has deformed sufficiently under a given force to show that the casing is not cemented in the bore hole, or whether so little deformation occurs that the casing is shown to beproperly cemented.

In order to more clearly exemplify the concepts of this invention, a preferred embodiment of the apparatus constructed in accordance with this invention is illustrated in Figures 1 and 2, of the attached drawings. In these figures-Figure 1, corresponds to the upper portion of the apparatus to be passed down awell casing, while Figure 2, shows a lower portion of this same apparatus, being a continuation of the view shown in Figure l. Jointly, the figures represent a complete and integral cement fault locator.

In thesefigures the numeral 30 designates a well bore hole drilled into the earth. The numeral 3] shows a well casing which has been placed in the bore hole. In'the annular space around the casing 31 and within the bore hole 30, it is assumed that cement has been positioned. This cement may be inserted in the annular space in any desired manner, or according to conventional practices in this regard. For the present purposes it may be assumed that cement has successfully penetrated the annular space around the casing,except for a portion of the casing adjacent the particular stratum 32. It is apparent, therefore, that the casing 3| will be bound by, or laterally supported by this cement parts required. This housing may suitably be supported in thewellby a cable 5, so that it can be lowered down 'intothe casing and may be pulled back to the "surface" of the earth in order to survey the extent "and" sufficiency of prior cementing operations. An electric motor 1' may be emplo'yedto provide the energy required to eri ical :a i rd m e l r s i t r casing 3i. The electric motor [may be driven by a atten '6 c rrieqimthe a a u or it may be drive H power lines running through cable .5. to the..'$l1rface' ,of v.thegfearth. The shaft of th''motor"l"is' coiinectdto a suitable gear assembly 8 that drives a crank arm 9 to translate the rotational motion of the motor shaft to a reciprocating motion suitable for driving the piston of the hydraulic pump I0. An intake check valve I2 is associated with the pump I so that on the upstroke of the piston of the pump, fluid may be pulled inwardly through valve I2 from the hydraulic reservoir or sump I3 into the pump. On the downward stroke of the piston, the fluid sucked in through valve I2 will be compressed by the piston to provide hydraulic pressure which may be used to deform the well cas ing. Thus a hydraulic cylinder I4 is associated with the pump I0. The hydraulic cylinder I I contains a piston rod, and piston combination directly connected to a rotary wheel member I5. A second rotary wheel member I5 may be fixed to the opposite end of the hydraulic cylinder I4, or if desired, may similarly be provided with a piston rod and piston arrangement. The effect of this construction is that when the piston of pump I0 moves downwardly hydraulic pressure is built up in the cylinder I4 to force the members I5 and I5 against opposite sides of the casing 3I. By this means it is possible to periodically apply a deforming force to this casing. It is preferred, but it is not essential, that a relief valve ll be associated with the pump In so that the hydraulic pressure built up in the cylinder I4 cannot exceed a predetermined value for which the release valve II may be set.

The remaining portion of the apparatus illustrated may consist of any desired means for measuring the force applied to the casing, and to measure the actual deformation of the casing. In other words, means are required to measure the force with which wheels I5 and I5 are forced outwardly from each other against the casing, and means are required to determine how much the casing yields under the applied force. A suitable means for accomplishing this is to run a hydraulic tap from cylinder I 4 to a bellows actuated recording pen I8. By this arrangement movements of the pen I8 will be controlled by the pressure in the cylinder I4 acting to control the expansion of the bellows I 6. In a somewhat similar fashion the deformation of the casing may be indicated by recording pen I9, actuated by bellows I"! of the hydraulic bleeder line connected to the hydraulic cylinder I I between the cylinder head of the cylinder, and the side of the piston opposite to the side to which hydraulic pressure is applied. Bellows H, the bleeder line, and the opening within the cylinder I4 to which the bleeder line has entry may be filled with a hydraulic fluid so that the movements of wheel I5 and its associated piston will change the hydraulic pressure in bellows H to actuate the pen I9.

It is preferred that the recording paper associated with recording pens I8 and I9 be driven by a wheel running along the casing wall. By this means it is possible to calibrate the record paper directly in terms of well depth so that the depth in the well at which a particular deformation is encountered may readily be determined. For this purpose, therefore, a wheel 2I may extend outside the housing I to roll along the casing 3I. This measuring wheel may drive suitable gears as diagrammatically illustrated to cause the rotation of record paper 20. It is a preferred feature of the gear drive illustrated that a clutch 22 is employed which will cause the paper to turn only when the wheel 2I is turned either clockwise or counterclockwise, as desired. Thus, as

illustrated the teeth of the clutch 22 are such that when the apparatus is passed downwardly in the well, the friction of the record paper drive will be suflicient so that the clutch teeth will simply slip over each other without turning the paper. However, when the apparatus is pulled upwardly in the well, the teeth will engage and turn the record paper.

It is apparent that should it be desired, suitable electrical expedients may be used to provide electrical signals indicating the deforming force applied to the casing, and the deformation of the casing, for recording at the surface of the earth through leads which may be carried in cable 5. Again, by such an expedient, electrical signals can be directly produced for recording in the apparatus.

The manner in which the apparatus described indicates improper cementing may be understood by reference to the portions of the records indicated on record paper 29. As shown, the pen I8 indicates a continuously cycling hydraulic pressure variation sinusoidally changing from a maximum to a minimum. It is apparent that when the casing 3I is properly backed by cement, the hydraulic pressure applied to the casing and recorded by pen I8 will be insufficient to materially deform casing 3I. Consequently, wheel I5, and its associated piston will not be moved outwardly enough to follow the variations in hydraulic pressure applied to the piston. In other words, pen I9 will draw a substantially straight line as shown in the lower portions of the record produced. However, if the casing 3| is not properly cemented in the bore hole, as adjacent stratum 32 for example, then on application of the hydraulic pressure in cylinder I4, wheel I5 will move outwardly to deform the casing. This then will alter the hydraulic pressure in bellows I'I causing pen I9 to draw a sinusoidal curve similar to that drawn by pen I8. Consequently, by inspection of a record such as that diagrammatically indicated, the apparatus of this invention indicates portions of the casing which are not properly cemented by the sinusoidal type line produced by pen I9 in this case.

What is claimed is:

1. An apparatus for locating uncemented portions of a well casing in place in a bore hole comprising a housing adapted for lowering into the casing, said housing including a hydraulic reservoir, a cylinder held in an essentially horizontal position by said housing, said cylinder having an interior chamber, a piston slidably held in chamber, a first projection on said piston e:-: tending laterally from said housing, a spring behind said piston urging said projection into contact with the wall of said casing, a second projection carried by said housing in the general vicinity of and on the opposite side from said first projection and extending laterally from said housing into contact with the opposite wall of said casing, a reciprocating pump communicating with said hydraulic reservoir, a conduit conmeeting said pump with said interior chamber behind said piston, drive means for periodically reciprocating said pump whereby a periodically varying force of known periodicity is produced within said chamber, and means for recording the extent of lateral motion of said piston with respect to said housing as a result of deformation of said casing whereby said lateral motion may be compared with the known periodicity of the force.

2. Apparatus according to claim 1 wherein said lateral motion recording means comprises an expansible bellows, a conduit connecting said bellows with said interior chamber on the side of said piston that carries said first projection, a reciprocating scriber actuated by said bellows, a movable record medium contacted by said scriber and means for moving said record medium past said scriber.

3. Apparatus according to claim 2 in which said means for moving said record medium past said scriber includes a wheel rotatably held by said housing in frictional engagement with the Wall of said casing whereby said record medium will most past said scriber in proportion to the movement of said housing lengthwise of said 15 2,4 20

casing.

4. Apparatus according to claim 2 including pressure change measuring means comprising a second expansible bellows, an additional conduit connecting said bellows with said interior chamher behind said piston and a second reciprocating scriber actuated by said second bellows, said second scriber contacting said record medium.

BEN W. SEWELL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 974,867 Eddy Nov. 8, 1910 2,150,070 Kregecz Mar. 7, 1939 Pelan June 28, 1949 2,552,433 7 Kirby May 8, 1951

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