US2826736A - Methods and apparatus for exploring boreholes - Google Patents

Description

2 Sheets-Sheet 1 March 11, 1958 HENRI-GEORGES DOLL METHODS AND APPARATUS FOR EXPLORING BoREHoLsS Filed Apr-11 21, 1955 HIS ATTORNEY.

March 11, 1958 HENRI-GEORGES DOLL 2,826,736

METHODS AND APPARATUS EXPLORING BOREHOLES 2 Sheets-Sheet 2 Filed April 2l, 1955 FIG Flc-5.4

A INVENTOR. HENRI GEORGES DOLL.

HIS ATTORNEY.

`the `well.

,a flowing well;

United States Parent-Q APPARATUS FOR EXPLORING BOREHOLES 7 claims. (ci. 324-2) METHODS AND This invention relates to methods and apparatus for exploring boreholes and, more particularly, pertains to Anew and improved methods and apparatus for detecting `waterchannels in the oil column of producing wells.

One procedure employed heretofore to locate intruding lwater involves the introduction of a conditioning 4fluid to the well and usually a hydrostatic lpressure'is established to provide a substantially static column in This conditioning fluid may, for example, have an electrical conductivity different from that of the intruding water and thus diffusion of the intruding water into the conditioning fluid maybe measured electrically. 1

The foregoing method has not always been entirely satisfactory since production of the well must be interrupted for an undcsirably long period. This is due'to thefact that often the establishment of the required static pressure condition is very time consuming and in many instances the procedure for establishing the pressure condition must be repeated a number of times before a satisfactory result can be obtained.

It is anobject of the present invention, therefore, to provide new and improved methods and apparatus for detecting water intrusion in a well that are not-subject `to the above-described deficiencies of prior arrangements.

.Another object of the. present invention is to provide newvand improved methods and apparatus for detecting water intrusion in a producing well requiring substan- 4 tially no interruption in production.

Amethod of determining fluid intrusion in a flowing well in accordance with the invention comprisesthe steps of passing a pair of closely spaced electrodes into .the well without substantially interrupting the ilow of uids from the-well, and obtaining indications of the electrical impedance between the electrodes while fluid continues to flow from the well. v To -carry out the foregoing method, it is `within the .contemplation of the present invention .to provide apparatus for detecting fluid intrusion .in a Well. This apparatus comprises a pair of electrodes supported in -spaced relationship relative .to thelongitudina'l axis of the well. Means are provided for displacingthe Aelectrodes about an annular path in a plane transverse to the aforesaid axis of the well, andthe apparatus 'further comprises means for deriving indications of'anelectrical characteristic of material between. the electrodes. Y

The novel features of the present invention. are set forth with particularity in the appended claims. .The present4 invention, both as to its o rganizationand manner of operation, together with further objects and .advantages thereof, may best be understood vby reference to the following description taken kin connection withthe accompanying drawings in which;

Fig. 1 is a View, partly in longitudinal cross xsection, of -a-lubricator device by means of iwhichapparatus `ernbodying `the present invention may be introducedfinto Eig.2,is-a View in longitudiiial-.crosssection:Ofappara- 2 rtus for detectingfluid intrusion in a well constructed in accordance Vwith the invention; f Fig. 3 represents a modification which `may be made to a portion of theapparatus shown -in Fig. 2; andv Fig. 4 is a view in longitudinal cross section of another modiiication which may be made to the apparatus of Fig. 2.

in Fig. l, a housing 1t! carrying apparatus embodying the present invention zis shown in Vassociation with typical well head equipment 11 at the surface of a well. VEquipment 11 includes a riser 12 connected at 'its upper `end to a sleeve 13 wherein a suitable pressure seal maybe provided in a conventional manner. Where the well pressure is too high for conventional seals, the sleeve 13 may enclose a pressure lubricator 14 as shown, which' receive a cable 19'which supports housing 10 for movement through the well so that it may be loweredy and Vraised through tubing 20 that traverses the well. VFluid channels 21 and 22 provide iluid communication between asection 23 in the lower-portion of bore 18 and a source 24 of sealing liquid viav suitable pipe connections. *The sealing liquid isY under a -pressure slightly higher than wellfpressure and excess sealing liquid -is passed via a port' 25 'in the upper end of gland sectionv 16 to a reservoir 26.'

norder to insert housingy 10 into the well, the well head valve is closed and cap 17 removed so that the gland sections 15 and 16 of lubricator 14 may be rermoved. yHousing 1G* is then lowered into riser l1?. and the lubricator is reassembled. The well head `valve may then be opened and pressure applied to lubricator 14 so that as'cable 19 is lpassed through lthe lubricator, a Vpressure seal is maintained and undue wear on the cable isprecluded. Thus, the well may be returned to production after avery short, insignificant interruption and the apparatus embodying the invention may be lowered through'tubing 20 'and into well casing 27 whereit may VVbeused to determineuid intrusion. 1For example, *water 'intrusion may occurvia a crack in casing 27 and may ow in continuous, vertical channels.

In Fig. 2, housing l0 is shown in operative position within casing 27, through which iluid 28 ows in an upward direction. The housing is` provided with upper rand lower sets 29 and 3i) of three or four bowed springs. These Asprings are biased outwardly relative to housing \10so^that;after-t11eapparatus leaves tubing 2t) and enters casing 27they move into engagement with the casing and Vthus serve tto center the housing in the casing.

' lf desired, an alternative varrangement of retractable, motordriven armsmay be employed to'center the housing -in thefcasiug, such as disclosed in the'ccpending applica- `tion of DJP. Saurenman and M. P. `Lebourg, tiled March .electrical Icontact .with-,the casing, `end members137 and .r3.3 .of electrically insulating material ,are ,lined tothe tends Patented Me 1.1 1.95

Yessayes L47 and 48 that extend through shaft 31 to slip rings ,49 and 50 mounted to, but electrically insulated from an upper end portion of shaft 31 within housing 10. A

`pair of brushes 51 and 52 complete sliding electrical connections between the slip rings 49 and 50 and a pair of conductors 53 `and 54. Conductors 53 and 54 are connected to the secondary winding of a one to twenty stepup transformer 55 having its primary winding connected to insulated leads 56, 57. These leads extend through cable `19 and are connected to a source 58 of electrical energy at the earths surface. Source 58 may supply an alternating potential at 110 volts and is provided with an operating switch 59.

l, `ln series with the secondary of transformer 55 is the primary winding of a .twenty to one step-down transformer 60. The secondary winding of transformer 60 is connected by insulated leads 61 and 62 `which extend through cable `19 to an indicator 63. The indicator 63 may, for example be a recording voltmeter in which the recording medium is displaced in proportion to movement of housing through'the well.

p In order to rotate electrodes 33r 34 and 39, 40 about an annular path in a plane transverse to the` axis of the well, a driving motor 64,.is mounted within housing 10 and is mechanically coupled to the upper end of shaftl by an appropriate gear system 65. The motor is electrically connected to conductors 56 and 57 and thus is coupled to source 58.

lf desired, housing 10 may be filled with a suitable electrically insulating fluid 66 and a bellows 67 may be mounted to the periphery of an opening 68 in the side wall of the housing. Thus, the fluid pressure within the .housing may be automatically regulated to compensate for the usual increase in pressure of fluid 28'experienced by the housing as it descends, and leakage of well fluids y,into the housing is minimized.

A typical embodiment of the invention may be adapted to be inserted into tubing on the order of 2 inches in diameter. The diameter of housing 10, the retracted diameter of bowed springs 29 and 30 and the retracted condition of electrodes 33, 34 and 39, 40 are arranged so that the instrument may move freely in the tubing, as shown in Fig. l. In the casing the springs 29 and 30 expand to engage the casing, and the electrodes 33,

34 and 39, 40 become extended as shown in Fig. 2.

Thus, switch 59 may be closed to energize transformer 55 and motor 64. Housing 10 may then be lowered or drawn upwardly throughcasing 27 with the electrodes 33, 34 and 39, 40 rotating about the axis of the housing. Since the housing is centered by bowed springs 29 and 30, the rotation of the electrodes occurs about an annular path in plane transverse to the axis of the Well.

Since a relatively high voltage, on the order of a few` thousand volts, is impressed across the electrodes, when they intercept an essentially vertical water channel, the resistance between them drops from a value of several megohms yto a few hundred ohms, and an electrical break down occurs across the electrodes. This immediately causes a high voltage to appear at the primary of transformer 60 and an indication is obtained. p

Alrecord of such indications is obtained in Vdevice 63 as a `function of depth of housing 10 in the well, and

thus the level at which water enters may be determined. 1

Inasmuch as source. 58 provides an alternating po- ItentialQlmotor 46 may be of the synchronous type `so that its speed is xed and the electrodes 33, 34 and 39, 40 rotate at a known speed. Accordingly, by using an indicator that is sufficiently fast in its response, and knowJ ing the4 vertical spacing between tlie electrodes and the resistivity of the intrudirig water, sonic indication of the` size of the intruding ,water column 27 iriay b`e obtained.-

It is therefore' evident that 'the' present invention pfr`o= vides arieffective method for determining water intrusion in a well. Moreover, apparatus embodying the present invention may be used in a flowing well without inter-j ruptng flow for any of more than an extremely short interval of time. Hence,.the present invention is riot sub1 ject to the deficiencies of prior arrangements.

It desired, the electrode wires may take the alternative form illustratedin Fig. 3. Intermediate coil spring 70 and insulator 71, wire 72 is provided with a plurality of sharply-pointed, thin lateral extensions 73. Since surface tension draws any oil film toward the wire, upon encountering water, the likelihood of an oil lm remaining on the extremities of the extensions is reduced. Thus, breakdown between electrode wires may be more readily v obtained.

Another electrode arrangement, shown in Fig. 4, coniprises thin, blade-like sets of electrode 75, 76 and77, 78. These electrodes are connected to a hollow shaft 79 by' respective pivots 80, 81, 82 and 83 for movement about respective horizontal axes. They extend through elongated, opposed opcnings 84 and 85 in shaft 79 and are biased about their axes by spiral springs 86, 87, 88 and 89 to bring insulated tips 90, 91, 92 and 93 into engagement with the inner wall of casing 94.

Pivotally connected to adjacent end portions of electrodes 75 and 77 is a rod 95 of electrically insulating material, which serves as a shaft for a roller 96 of elec= trically insulating material. Similarly, a roller 97 is supported by a shaft 98 pivotally connected to adjacent end portions of electrodes 76 and 78. Thus, when shaft 79 is rotated, the electrodes are driven about annular paths with the rollers 96 and 98 riding on the inner wall `of casing 94.

A retracting sleeve 99 is slidably supported by shaft 79 and is provided with opposed openings 100 and 101 through which the electrodes project. To retract thc electrodes, sleeve 99 isdriven downwardly and upper portions 102 and 103 of the peripheries of openings 100 and 101 engage electrodes 75 and 76. Since these electrodes are connected to electrodes 77 and 78 by rods 95 and 98, all the electrodes are thus pivoted against the bias of springs 86-99 toward the axis of shaft 79. Conversely` to condition the apparatus for operation, sleeve 99 is driven upwardly and the electrodes 75-78 are thereby permitted to be extended.

While particular embodiments of the present invention has been shown and described, it is apparent that changes and. modifications may be made without departing from this invention on its broader aspects, and therefore the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

I claim:

l. A method of detecting fluid intrusion in a flowing well which comprises the steps of: passing a pair of closely spaced electrodes into the well without substantially interrupting the flow of fluids from the well; continuously displacing said electrodes effectively to examine substantially all the material in a plane transversefto the `axis of the well; and obtaining indications of an electrical characteristic of material between the electrodes while fluid continues to flow from the well.

2. A method of detecting fluid intrusion in a flowing well which comprises the steps of: passing `a pair of 'closely spaced Velectrodes into the well without substan- Vtially interrupting the flow of fluids from the well; rotating said electrodes at a predetermined speed about an annularpath laterally displaced from and enclosing -the axis of the Well and disposed in a plane transverse to the axis of the well; and obtaining indications of an electrical characteristic of material between the electrodes while lluid continues to flow from the well.

3. Apparatus for detecting fluid intrusion in a well comprising: a pair of electrodes, adapted to traverse a well; means for supporting said electrodes in spaced relationship relative to the longitudinal axis of the well for rotation about an annular path in a plane transverse to the aforesaid axis; means for displacing said electrodes about said path; and means for deriving indications of an electrical characteristic of material between said electrodes.

4. Apparatus for detecting huid intrusion in a Well comprising: a pair of long, narrow conductive wires adapted to traverse a well extending radially a distance on the order of magnitude of one-half the diameter of the well in spaced parallel relationship to one another relative to the longitudinal axis of the well, said wires being supported for rotation about an annular path in a plane transverse to the aforesaid axis; means for displacing said wires about said path; and means for deriving indications of an electrical characteristic of material between said wires.

5. Apparatus for detecting fluid intrusion in a well comprising: a housing adapted to traverse a well; a pair of electrodes supported by said housing in spaced relationship relative to the longitudinal axis of the well for rotation about an annular path in a plane transverse to the aforesaid axis; means connected to said housing for maintaining a portion thereof and said electrodes in fixed relation to the aforesaid axis as said housing is passed through the Well; means for displacing said electrodes about said path; and means for deriving indications of an electrical characteristic of material between said electrodes.

6. Apparatus for detecting iluid instrusion in a well comprising: a carrier adapted to traverse a well; a pair of electrodes supported by said carrier in spaced relationship relative to the longitudinal axis of the well for rotation about an annular path in a plane transverse to the aforesaid axis; means connected to said carrier for maintaining a portion thereof and said electrodes in substantially fixed relation to the aforesaid axis as said carrier is passed through the Well; means for displacing said electrodes about said path; means for impressing a relatively high voltage .between said electrodes to effect an electrical discharge therebetween upon encountering material in the Well of a predetermined electrical conductivit; and means for deriving indications responsive to such an electrical discharge.

7. Apparatus for detecting uid intrusion in a Well comprising; a carrier adapted to traverse a well; a shaft supported by said carrier for rotation about a given axis; a pair 'of electrodes supported by said shaft, electrically insulated from one another, and extending away from said shaft in essentially parallel relation to one another; means connected to said carrier for maintaining a portion thereof in substantially lixed relation to the longitudinal axis of the Well with said given axis essentially aligned With the aforesaid longitudinal axisv as said carrier is passed through the well; means for rotating said shaft thereby to displace said electrodes about' an annular path; and means for deriving indications of an electrical characteristie of material between said electrodes.

References Cited in the file of this patent UNITED STATES PATENTS 1,536,007 Huber Apr. 28, 1925 2,210,205 Elliott Aug. 6, 1940 2,248,982 Gillbergh July l5, 1941 2,295,738 Gillbergh Sept. l5, 1942 2,300,206 Clark Oct. 27, 1942 2,412,363 Silverman Dec. l0, 1946 2,517,603 Silverman Aug. 8, 1950 f FOREIGN PATENTS 673,872 France lan. 21, 1930

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