US2554174A

US2554174A - Well logging method and apparatus

Info

Publication number: US2554174A
Application number: US778683A
Authority: US
Inventors: Doll Henri-Georges
Original assignee: Schlumberger Well Surveying Corp
Current assignee: Schlumberger Well Surveying Corp
Priority date: 1942-06-13
Filing date: 1947-10-08
Publication date: 1951-05-22
Anticipated expiration: 1968-05-22

Description

y 1951 HENRI-GEORGES DOLL 2,554,174

WELL LOGGING METHOD AND APPARATUS Original Filed June 13, 1942 3 Sheets-Sheet 3.

SOURCE OF ELECTRICAL ENERGY REfiORDER INVENTOR. HENRI-GEORGES sou.

H IS AT TORNEYS.

May 22, 1951 HENRFGEORGES DOLL WELL LOGGING METHOD AND APPARATUS Original Filed June 15. 1942 3 Sheets-Sheet 2 v sNvENToR.

HENRIGEORGES DOLL 5%EIATTCRNEYS y 195l HENRI-GEORGES DOLL 2,554,174

WELL. LOGGING METHOD AND APPARATUS 3 Sheets-Sheet 3 Original Filed June 13, 1942 84 FIG. 5.

RECORDE RECTIFIER 33 FIG. 4.

h INVENTOR.

HENRI-GEORGES DOLL HIS ATTORNEYS.

Patented May 22, 1951 WELL LOGGING METHOD AND APPARATUS Henri-Georges Doll, Houston, Tex., assignor to Schlumberger Well Surveying Corporation, Houston, Tex., a corporation of Delaware Original application June 13, 1942, Serial No.

446,888. Divided and this 8, 1947, Serial No. 778,683

application October 8 Claims. (Cl. 175182) The present invention relates to methods and apparatus for investigating earth formations traversed by a bore hole, and more particularly to a new and improved method and apparatus for determining the depth and thickness of permeable formations traversed by a bore hole.

This application is a division ofmy copending application Serial No. 446,888, filed June 13, 1942, for Method and Apparatus for Investigating Earth Formations Traversed by a Bore Hole, now Patent No. 2,433,746, granted December 30, 1947.

The above mentioned copending application discloses that alternating electrofiltration po tentials can be created by producing periodic pressure fluctuations in the bore hole liquid in the vicinity of permeable formations, which alternating potentials may be availed of in locating permeable formations. The basic theory is fully set forth in that application and will not be repeated herein.

The present application is addressed to methods and apparatus of the above character in which the periodic pressure fluctuations are produced by directing a jet or jets of liquid into the bore hole liquid.

The invention may be better understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

Fig. l is a schematic diagram in longitudinal section of apparatus constructed according to the invention for producing periodically variable potentials related to electrofiltration potentials in a bore hole;

Fig. 2 illustrates a curve of electrofiltration potentials such as might be obtained by means of the apparatus shown in Fig. 1;

Fig. 3 is a schematic diagram in longitudinal section of a further modification of the invention utilizing a liquid operated turbine in the bore hole for producing pressure variations therein;

Fig. 3a is a View in section taken along line 3a-3a of Fig. 3 and looking in the direction of the arrows;

Figs. 3b and 3c are sectional views of portions of the apparatus shown in Fig. 3, taken along lines 3b-3b and 3.c 3c, respectively, and looking in the direction of the arrows;

Fig. 4 shows the apparatus of Fig. 3 in position in a bore hole and illustrates schematically the electrical connections employed; and

Fig. 5 shows an illustrative curve which might be obtained with the apparatus of Figs. 3 and 4.

Referring to Fig. 1, the apparatus I0 comprises a casing 5| suspended on a conventional type bail 52 secured to the supporting cable 21 in the bore hole l2 which contains a column of liquid l l. Mounted in the upper portion of the casing 5| is a downwardly extending conduit 53 having a large mouth 54. The conduit 53 converges downwardly and divides into two oppositely directed

conduits

55 and 56 located in the lower portion of the casing 51.

At the junction of the

conduits

55 and 56 is mounted a conventional type clapper valve 51 which is adapted to be moved periodically from the position shown in full lines to the position shown in dotted lines in the drawing. This may be accomplished in any suitable manner, as, for example, by mounting an arm 553 having a longitudinal slot 59 therein on the shaft of the clapper valve 5'5. Within the slot 59 is adapted to be received a pin 68 secured on a rotatable disc 61 driven by a conventional type electric motor 62. One terminal of the motor 62 is connected to the conductor 26 in the supporting cable and its other terminal is grounded to the casing 5! at the point 63. The cable conductor 26 may be connected in series with a switch 28 to one terminal of a suitable source of electrical energy 29, located at the surface of the earth, the other terminal of which may be grounded at 30.

In operation, the switch 28 is closed at the surface of the earth, supplying electrical energy from the source 29 to the electric motor 62. The disc 6| begins to rotate and moves the clapper valve 51 periodically from the position shown in heavy lines to that shown in dotted lines. Meanwhile, the casing 5| is moved upwardly through the bore hole by applying tension to the supporting cable 21 so that the bore hole fluid l l is directed through the conduit 53 and alternately through the

conduits

55 and 56.

The jetting action of the bore hole fluid ll produced in its passage through the diametrically

opposite conduits

55 and 56 produces a vigorous lateral vibration of the casing 5| and alternately compresses the bore hole liquid l I in the vicinity of the outlets of the

conduits

55 and 56. As described above, the periodic variation in the pressure of the bore hole liquid II is accompanied by corresponding variations in the electrofiltration potentials existing in the vicinity of permeable formations.

These potential variations may be picked up, for example, by measuring the potential difference between two insulated

electrodes

64 and 65 located on opposite sides of the casing 5| in the vicinity of the

conduits

55 and 56. The

electrodes

64 and 65 may be connected to the

conductors

33 and 49 in the supporting cable and the potential differences picked up are measured by the recording apparatus 34 at the surface of the earth.

A representative curve, such as might be obtained with the apparatus shown in Fig. 1, is illustrated in Fig. 2 of the drawings. As shown in this figure, the curve of spontaneous potentials at the level of relatively permeable formations has approximately a sinusoidal shape and its frequency is the same as the frequency of vibration of the apparatus in the bore hole.

In the embodiment illustrated in Fig. 3 of the drawings, a hydraulic turbine is employed to produce periodic variations in the pressure of the bore hole liquid at different depths in the bore hole. Referring to Fig. 3, the apparatus comprises a casing 66 at the upper extremity of which are mounted a plurality of flexible fins 61 which serve to maintain the casing 66 in fixed relation to the axis of the bore hole I2. Although any desired number of fins 61 may be used, preferably four are provided, which are disposed 90 apart, as shown in greater detail in Fig. 3a, and they may be made of any suitable resilient material, such as rubber or neoprene, for example.

Secured to the lower portions of the flexible fins 61 are a plurality of flaps 68 made of any suitable material, such as canvas, for example, which extend between the outer edges of adjacent fins 61, as shown, to form a funnel for directing the bore hole liquid II to a plurality of fluid inlets 69 formed in the casing 66. It will be noted that when the casing 66 is lowered into the bore hole I2 the canvas flaps 68 will be collapsed by the movement of the casing 66 through the bore hole liquid II. On the other hand, when the casing 66 is raised in the bore hole the fiaps 68 will be expanded into the operative position, forming a large funnel as shown in the drawings.

The fiuid inlets 69 in the casing 66 communicate with a chamber I0, which in turn communicates with the inlet port II of a conventional type hydraulic turbine I2. The turbine I2 comprises two sets of stator blades 13 and I4 between which is rotatably mounted a rotor I5 having a plurality of blades I6 mounted thereon.

In order to provide for periodic pressure variations in the bore hole liquid I I, a bottom closure member I1 is provided between two adjacent blades I6 on the turbine rotor I5, as shown in greater detail in Fig. 3b. Also, similar bottom closure members I8 and 18a are provided be- Ji-L' tween two pairs of adjacent fixed blades I4 below the rotor and outlets 80 and 89a are formed directly opposite the two pairs of adjacent blades I4 which have been so closed off.

While the device will function with only one outlet 80, it is preferable to provide two in order to increase the vibrational energy imparted to the bore hole liquid. It is also desirable to have one or more less blades on the rotor I5 than there are stator blades I4. With this construction, the closure member 11 on the rotor I5 subtends a greater are than the passages between the blades 14 to which the bottom closure members 18 and 18a are secured, and reduces to a minimum any leakage from the outlets 853 and 80a when the rotor bottom closure member TI lies over the stator blades I4 to which the closure members I8 and 18a are secured.

In operation, the casing 66 is lowered to the bottom of the bore hole on the supporting cable 21 (Fig. 4). While it is being lowered, the flaps 68 between the fins 61 are collapsed so that they do not impede the movement of the apparatus in the bore hole. The apparatus is then raised, whereupon the flaps 68 expand to form a funnel, as shown in the figure. This funnel directs the bore hole liquid II through the fiuid inlet 69 and the chamber 10 to the turbine inlet I I, causing the rotor I5 thereof to rotate at a speed which depends upon the speed at which the apparatus is moved through the bore hole I2.

So long as the bottom closure member I? between the two rotor blades IB is not directly over either of the two pairs of adjacent blades M to which the

bottom closure members

76 and 78a are secured, water will pass through the turbine I2 and through the outlets 8i) and 86a from which it will be jetted radially against the wall of the bore hole I2. The water will also be continu ously exhausted through the turbine outlets 8|. However, when the bottom closure I1 moves directly over either of the two pairs of adjacent blades I4 to which the bottom closures I8 and 18a are secured, practically no fiuid will pass through the corresponding opening 33 or 62a but substantially all the fluid will pass through the other opening and the turbine outlet BI. Accordingly, as the rotor I5 rotates, intermittent and alternate jets of water will be directed from the outlets S0 and 80a, thereby producing a lateral vibration of the casing 66 and periodically varying the pressure of the bore hole liquid II at the level of the apparatus in the bore hole.

The variations in the electrofiltration potential produced by the periodic variations in the pressure of the bore hole liquid I I may be picked up by a pair of

insulated electrodes

82 and 83 located on opposite sides of the casing 66 near the outlets 80 and 80a. The

electrodes

82 and 83 may be connected to the conductors 33 and 19 in the supporting cable 21 (Fig. 4) to a conventional type rectifier 84 at the surface of the earth, the direct current output of which is impressed upon the recording apparatus 34. The rectifier 84 serves to rectify the periodically varying electrofiltration potential which is produced in the bore hole I2, so that the curve recorded has substantially the shape shown in Fig. 5 of the drawings.

Where a single outlet 80 is employed, the pressure variations produced might be augmented by providing a similar closure member for another pair of adjacent rotor blades 16, preferably at a position diametrically opposite the closure member 'I'I, increasing the number of rotor blades 16. if necessary, to do this. This would, of course, double the frequency of vibration of the apparatus.

Inasmuch as the periodic pressure changes in the modification described above are produced and controlled by mechanical and hydraulic means, there are no current carrying conductors in the supporting cable 21 other than the

conductors

33 and 49, which transmit the electrofiltration potentials to the surface of the earth. Accordingly, the electrofiltration potentials picked up may be very accurately measured.

The alternating electrofiltration potentials may be measured in other ways than those shown above. For example, the recorder 34 might be connected to one electrode located substantially at the level of the apparatus in the well and a reference electrode located either a short distance away or at the surface of the earth. As a further modification, indications might be obtainedof the voltages between each of the two electrodes in Figs. 1 and 3 and ground.

The invention thus provides a new and improved method and apparatus for obtaining indications of electrofiltration potentials apart from other continuous potentials that may be present in a bore hole. By producing a localized and periodically variable pressure variation at different depths in the bore hole, continuous electrofiltration potentials may be changed to alternating potentials that can be readily separated from other continuous potentials which may be encountered. Accordingly, the invention enables accurate indications of electrofiltration potentials to be obtained without taking any special precautions even in wells located in the vicinity of relatively strong telluric currents.

The several embodiments described above are intended to be illustrative and not restrictive. Numerous modifications in form and detail may be made in those embodiments Within the scope of the following claims.

I claim:

1. A method of investigating earth formations traversed by a bore hole containing a column of liquid, comprising lowering into the bore hole a body having fluid outlet means therein, periodically directing a jet of fluid from said oulet means into the bore hole liquid at different depths in the bore hole, thereby creating periodically varying electrofiltration potentials in the vicinity of permeable formations, and obtaining indications of said varying potentials between a point in the vicinity of said jet of fluid and a point at a reference potential.

2. A method of investigating earth formations traversed by a bore hole containing a column of liquid, comprising lowering into the bore hole a body having a plurality of spaced apart outlets therein, periodically and alternately directing jets of fluid from said outlets in different direc tions into the bore hole liquid at different depths in the borehole, thereby creating periodically varying electrofiltration potentials in the vicinity of permeable formations, and obtaining indications of said varying potentials between a point in the vicinity of said jet of fluid and a point at a reference potential.

3. Apparatus for investigating earth formations traversed by a bore hole containing a column of liquid, comprising a body adapted to be lowered into a well and having outlet means therein, means for periodically directing a jet of fluid from said outlet means into the bore hole liquid at different depths in the bore hole, thereby creating periodically varying electrofiltration potentials in the vicinity of permeable formations, and means for obtaining indications of said varying potentials between a point in the vicinity of said jet of fluid and a point at a reference potential.

4. Apparatus for investigating earth formations traversed by a bore hole containing a column of liquid, comprising a body adapted to be lowered into a bore hole and having spaced apart outlets formed therein, means for periodically and alternately directing jets of fluid from said body outlets into the liquid at different depths in the bore hole, thereby creating periodically varying electrofiltration potentials in the vicinity of permeable formations, and means for obtaining indications of said varying potentials between a point in the vicinity of one of said jets and a point at a reference potential.

5. Apparatus for investigating earth formations traversed by a bore hole containing a column of liquid, comprising, a casing having a mouth at the upper end thereof, said mouth converging downwardly and dividing into at least two laterally extending conduits, means for alternately blocking the passage of fluid through said conduits, an electrode associated with said casing and movable therewith, and means for exhibiting a function of alternating potentials existing between said electrode and a ground point.

6. Apparatus for producing periodic variations in the pressure of the liquid contained in a bore hole drilled into the earth, comprising, a casing adapted to be lowered into a bore hole, a fluid driven turbine in the casing, said turbine having rotor blades and stator blades, means for directing bore hole liquid to the turbine, means for blocking the passage of fluid between two adjacent rotor blades, means for blocking the passage of fluid between two adjacent stator blades, and an outlet in the casing communicating with the space between said last named two stator blades.

'7. Apparatus for investigating earth formations traversed by a bore hole containing a column of liquid, comprising, a casing adapted to be lowered into a bore hole, a fluid turbine in the casing, said turbine having stator blades and rotor blades, means for blocking the passage of fluid between two adjacent rotor blades, means for blocking the passage of fluid between two adjacent stator blades, an outlet in the casing, communicating with the space between said last named two stator blades, means for directing fluid to the turbine when the casing is raised through the bore hole, an electrode associated with the casing and movable therewith, and means for exhibiting a function of alternating potential differences between said electrode and a point of reference.

8. A method of investigating earth formations traversed by a bore hole containing a column of liquid, comprising lowering into the bore hole a body having spaced apart outlets therein, periodically and alternately directing jets of fluid from said outlets in dilferent directions into the bore hole liquid at different depths in the bore hole, thereby creating periodically varying electrofiltration potentials in the vicinity of permeable formations, and obtaining indications of said varying potentials between spaced part points in the vicinities of said jets, respectively.

HENRI-GEORGES DOLL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,190,686 Slichter Feb. 20, 1940 2,214,786 Bishop Sept. 17, 1940 2,249,769 Leonardon July 22, 1941 2,313,384 Lee Mar. 9, 1943 2,364,957 Douglas Dec. 12, 1944