DE2113817A1 - Core recovery device - Google Patents

Description

Maurice Pierre Lebourg, 3700 Greenway Plaza, Suite U28, Houston, Texas 77027, USA ₀

Core recovery device

The invention relates to a drill core retraction device, in particular for soft, non-consolidated formations. The invention also relates to a method for generating and retrieving such drill samples in a condition that exactly corresponds to the formation stratifications.

It has been found difficult to collect drill samples from soft, unconsolidated formations and from fractured rock because these samples are often washed out by the fluid used in drilling or crumble during application and handling so that the formation stratification in the drill sample does not become stratified corresponds in the examined soil,

PUr the investigation and the application of core samples or cores from soft or unconsolidated Forma · Special devices are functions required to the disintegration or displacement of the drill core gen to avoid the same when Aufbrin.

There are already drill sample application containers known which

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be able to bring up non-solid drill cores undamaged. These known drilling sample containers comprise an elastic one Sheath that is movable upward into a tubular part and surrounds the core as soon as it enters the tubular part. Such devices produce an axial Kraft auf.den Bohrkern, since the upward force of the same must move the casing. In addition, the well-known Devices have the disadvantage that they do not allow sealing 'the elastic sleeve and that the Bohrprobema- ™ material from the drill sample container during application fall or get mixed up. Another disadvantage is that the moving parts of the drill sample container can be easily damaged. Devices of this type are disclosed in U.S. Patents 3,092,191 and 2,927,276.

Another known device (U.S. Patent 2,895,691) a collapsible sleeve made of a non-elastic material is used to convey non-rigid drill samples, which below the core after completion of the drilling sampling can be collapsed.

Attempts have also been made to promote non-rigid cores by making an elastic sleeve by means of an independent one Druckcjelle has closed to the drill sample to be firmly enclosed after the completion of the drilling sampling (USA patent 3 480 093).

The invention is based on the object of a method and a device for removing and conveying drilling samples to create in their original state, which siqh for both rotatable and non-rotatable Bohrkerngntnahmevorrichfcungen and method is suitable and which exerts only minimal forces on the drill sample,

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The method according to the invention is essentially to be seen in the fact that a drill core from the formation to be examined is cut out that this core is brought in the axial direction in an expandable sheath that on the Outer surface of the shell, a fluid pressure is applied to compress the shell above the core, and that the Fluid pressure behind the sheath is adjusted so that the sheath expands from its contracted state and the core.

The device according to the invention for carrying out this method comprises a cutting device for cutting through the formation for the purpose of obtaining a book, a stretchable sheath, which is arranged above the cutting device and can accommodate this inside, and a Pressure generating means for generating a fluid pressure on the outer surface of the shell, the fluid pressure is selected to be greater than the pressure prevailing within the envelope in order to close the envelope in its contracted position hold until the core is taken up by the sheath.

Valves can be provided which ensure that the casing in its contracted state above the g Drill core is that, however, fluid is released behind the sheath as soon as the drill core enters the sheath and expands it.

According to a particular embodiment, the device according to the invention has a core drill that has a Fluid flow generated in the vicinity of the cutting device, to aid in the formation of the formation and the formation of a drill core, whereby the pressure drop from the Flow obstruction is used at the cutting area of the cutting tool to create a pressure differential, so that the shell contracts and remains intact

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Column of the drill core material is drawn into the sheath and can be brought out later for examination. Can by fluid pressure on the shell of the device sustained during the entire drill core tapping, with no further pressure line in most cases is required for the tool.

The fluid pressure behind the contractible shell is influenced by valves, which ensure that the fluid pressure behind the envelope is greater than the fluid pressure within the same by a certain amount Amount, so that the casing accommodates the drill core in an elastically resilient manner and is below the same during the upward production of the drill core contracts so that it cannot fall out «.

33 The term fluid is meant in the following in its most general form, namely as a fluid, i.e. what be liquid or gaseous. Usually, in particular In rotary drilling rigs, the drilling fluid is commonly used to put pressure on the contractible Exercise envelope. However, the invention can also be used for gas drilling, e.g. for drilling with air according to a rotating process, in which case the gas pressure then makes the envelope tighter.

As the following example shows, the invention Use not only on rotating drilling rigs, but also on other drilling samplers.

The invention is illustrated below with reference to schematic drawings additionally described in several implementation examples ο

Figure 1A is a partial view of the upper part rich of a core generating device

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according to the invention for rotating applications.

Figure 1B is a partial longitudinal section of the lower part of the device of Figure 1A.

Figure 2 is a longitudinal section of a device according to the invention, in which the sleeve for the purpose of recovery of the drill core is narrowed.

Figure 3 is a cross-section along line 3-3 of Figure 2 showing the outline of the constricted location of the envelope. ·. _Λ

Figure 4- is a cross-section corresponding to Figure 3, but with a different sheath.

FIG. 5 shows a further exemplary embodiment of a drilling sampling device in which the device does not rotate and is particularly suitable for layers close to the ground under water suitable.

The drill core removal device according to Figures 1A, 1B and 2 is intended to be sunk into a borehole made by a rotary drill. The device includes an upper mandrel which engages with the | Rotates drilling rope and from which an outer pipe extends, which rotates with the mandrel and the drill rope. A drill bit sits at the lower end of this outer tube. An inner mandrel is suspended from the outer mandrel by means of bearings so that it does not rotate with the drill rope In the inner mandrel, the core removal device is housed compartment of the invention.

The Bohrkerneatnahmevorrichtung 100 can be up to the Set down the bottom A of a borehole B by means of a pipe string, the lower region 11 of which is shown in FIG. 1A

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is. The lower end of the pipe string is screwed to the upper end of the outer dome (hereinafter referred to as the outer sleeve). The lower end of the pipe string 11 and the upper end of the outer sleeve 13 form a central channel 15 'through which the drilling fluid, such as drilling mud, circulates through the pipe string to the drill bit. In the lower portion of the outer sleeve 13 there are flow channels 17, is pushed by the fluid through the device _t is as explained below.

An outer tube 21 is screwed onto the outer sleeve 13 and extends downward and the lower area surrounds the drill core removal device. The outer tube preferably consists of a number of tubular areas 23, 25 and 27 so that the length of the core removal device can be changed according to the desired depth of the drill core.

The lower region of the outer sleeve 13 is screwed to an inner tubular sleeve 29, which together with the Bonrung 38 in the lower end of the outer sleeve 13 forms a cylindrical recess which connects to the upper end 40 of the inner dome 39 is adapted. The inner surface of the inner tubular sleeve 29 is provided with bearing surfaces 31, which form a running surface for bearings 33. These bearings lie against bearing surfaces 41 on the outer surface of the inner Mandrel 39 and support it with respect to the outer sleeve 13 and the pipe string 11. It can of course also use other bearing arrangements.

The outer tube 19 and the inner tube sleeve 29 delimit the upper region of a fluid channel 20. This extends calibrate up to the drill bit 30 and directs drilling fluid: downwards into this * The drill bit forms a diamond drill bit, however, any other suitable drill bit can be used.

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The part of the device in which the drill core is received and conveyed is fastened to the inner mandrel 39 will. A valve seat is located on the inner mandrel 39 at 34A 42 screwed in, which interacts with a valve ball 4-3, which is located in the bore 44 of the inner dome 39. At the lower end of the same is a pressure core receiving sleeve 47 screwed, which has a central bore in its upper area in which a tubular extension 36 of a filler carrying part 37 can be moved longitudinally with the interposition of a sight ring 51 is mounted · The lower area of the core receiving bushing 47 is provided with a core | holder 69 is provided, which is above the drill bit 30. When the lower area of the formation from which a drill core is to be removed, is sufficiently strong so that the core holder can be effective, the drill core can be undamaged hereby hold back.

An expandable, elongated sheath 53 is fastened in a flow-tight manner to the shell support part 37 at the point 55. The lower Area of this shell is connected to the lower area of the core receiving bushing 47 in a flow-tight manner, and by means of a clamping ring 58 and a sealing ring 56.

Ee it should be mentioned that behind the shell 53 and between the- | ser and the Kernaufnähmebuchse 47 an annular space 67 is present, which is via an annular shape with the passage 65 between the sleeve support part 37 and the core receiving bushing 47 with a chamber 71 in connection. In the upper area of the KernaufnahMebuchse 47 two pressure-dependent Hicks chi agven tile 49 and 79 are provided, which are between the chamber 71 and the fluid channel 2Θ. The valve 49 forms a check valve which allows a flow from the fluid channel 20 into the chamber 71 as a function of certain pressure gradients at the valve. In the same way, the back stroke valve 79 enables a fault

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murig from the chamber 71 into the fluid channel 20 in one certain pressure gradients in the opposite direction of flow

Therefore, if there is a sufficiently high pressure gradient between the fluid channel 20 and the chamber 71 is present, the check valve 49 opens and allows a flow the drilling fluid through the check valve 49 into the chamber 71 'until the pressure gradient is below the threshold value of the check valve 49 decreases. With a sufficiently high pressure gradient in the opposite direction between the Chamber 71 and the fluid channel 20 opens the check valve 79 and lets fluid from the chamber 71 into the fluid channel 20 stream.

The check valve 49 is set so that it opens at a pressure gradient and fills the annular space 67, which is smaller than the pressure gradient of the check valve 79 for opening the same.

The mode of operation is explained in more detail below. During drilling, the pipe string 11 rotates so that the drill bit 30 is also rotated. A drilling fluid, e.g. aqueous or oily drilling mud, circulates downward through the central channel 15 and the flow channels 17 into the annular fluid channel 20 * Because of the relatively narrow opening of the same, there is a fairly large pressure loss due to friction when the drilling fluid moves through the fluid channel 20 . As a result, the dynamic flow _{pressure at point P 1} compared to the channel leading to check valve 49 is considerably greater than the dynamic pressure at point p "in annular channel 68 of drill bit 30. At dynamic pressure, the fluid pressure, which is produced by increasing the hydro · Static pressure arises, not taken into account. The pressure-

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drop in dynamic pressure leads to friction losses in the annular fluid channel 20 between these two locations.

When the drilling fluid reaches the drill bit 30, it enters the annular channel 68 and from there mainly through the bottom of the. The drill bit to the outside via the channels 59 and supports the drilling process. Small channels 61 are provided between the annular channel 68 and the interior of the drilling device, which serve to equalize pressure between the interior and the type of flow emerging from the channels 59. The drilling fluid flows in the direction of arrow 11. Because of this pressure equalization, the dynamic pressure within the drill core 60 is essentially equal to P ₂ .

When using this tool, the fluid flow is started before drilling, so that immediately thereafter a pressure builds up at the point P ₁ opposite the passage 15, which is so large that the check valve 49 opens and a fluid flow into the chamber 71 and through the Annular space 67 between the core receiving bushing 47 and the shell 53 allows. The sheath 53 is constructed in such a way that the unsupported area of the same between the clamping ring 58 and the sheath holder 55 is narrowed as a function of the fluid pressure behind the sheath in the annular space 67 * FIG. 3 shows a typical sheath 53 in the constricted state.

The pressure gradient required to open the check valve 49, so that a flow into the chamber 71 takes place, is very small and not as great as the pressure drop between the points P ₁ and P ₂ . Since the fluid pressure inside the core container 6o before the start of drilling is at the side equal to P ₂ , there is no internal fluid pressure in the sleeve 53 which counteracts its narrowing.

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half and outside of the envelope are at the same height, any pressure differences that _{could arise between points P 1} and P ₂ , for example, are ultimately compensated O

The check valve 79 _S, which is connected to the chamber 71 and ultimately to the annular space 67, is set so that it opens at a higher pressure gradient than the check valve 49. When the latter, for example, i-φ play at a pressure difference of 0.15 atü responds between the fluid channel 20 and the chamber 71, the check valve 79 only opens at a negative pressure gradient of 0.7 atü between the fluid channel 20 and the chamber 71. The combination of these two check valves 49 and 79 therefore enables fluid to be stored at a certain pressure within the annular space 67 behind the cover 53 "

When drilling is started, the fluid is allowed to flow around further, so that the drilling process and the Removal of the formation is supported by the nozzle action of the fluid from the channels 59 and a drill core 60 is generated, which enters the core container, wherein the φ narrowed envelope 53 is opened and at the same time because of the the pressure generated by the drill core elongates the casing and the annular space 67 as a result of the volume of the drill core 60 generated pressure on the inside of the shell 53 is reduced. The check valve 49 opens and allows fluid to drain from the back of the envelope. Figure 1B shows the state in which the drill core 60 is partially in the Sheath 53 is introduced, which in the area 54 above of the entering drill core is still narrowed by the fluid pressure in the annular space 67. This fluid pressure also forms lateral support for the core in the area 52; in which the drill core has already entered the casing 53 is,

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The setting of the opening point of the check valve 79 should be at a higher value than for the check valve 49 »but not so large that a Pressure is exerted on the drill core 60, which crushes or deforms it when it is introduced into the constricted sheath will.

The check valves. 49 and 69 can also be set up for variable print settings.

FIG. 2 shows the use of a device according to the ™ Finding for picking up and conveying loose drill cores. After the drill core has been produced, the rotary movement of the pipe string and the drill core removal device is ruptured and the entire device lifted from the bottom of hole A, a continuous flow of fluid through passed the annular fluid channel 20 into the drill bit will. The entire borehole is typically filled with fluid.

! times the raising of the core sample removal device from the bottom of the hole, the lower part of the loose falls Bonrker ** nes from the Bohrprobenentnahmevorrichtung to the ground g of the borehole at the location 79 down. When the lifting is carried out 'slowly and continue fluid flow during the lifting, or even increased, a constant pressure difference at the rear is check valve 49 present, which tends to allow fluid in the annulus 67 behind the casing 53 and ^ s lower area of the casing where the drill core material falls out, so that the upper, major region of the drill core is prevented from falling and in its original configuration | persists. I.

Venn the HUXIe is completely narrowed at point 75, can

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Fluid flow are interrupted because the fluid pressure in the .Ring space 67 is sufficient to hold the drill core during conveyance.

In practice, as soon as the Bohrkernentnahmevorr performance has reached the bottom of the borehole, the fluid flow switch on in order to constrict the sheath 53 over practically its entire length. Then the drilling is started when the fluid flow continues and with a higher fluid pressure behind the sleeve 53 than within the same.

If now the core removal device from the bottom of the Borehole is raised, the fluid flow is preferred increased to ensure that the full pressure differential on the case there is * as it is through the settings the check valves 49 and 79 is set. This results in a greater squeezing of the shell in the ground * when the lower parts of the drill core fall off.

When the drill core removal device is raised, the hydrostatic pressure above the same is reduced, and Fluid escapes from the annulus 67 through the check valve 79 when the fluid pressure is within the envelope decreases. The combination of the two check valves acts in such a way that there is constant fluid pressure within of the annular space 67 is maintained, which is greater than the fluid pressure within the drill core, so that the Sheath 53 is held in its squeezed-together position shown in FIG.

FIG. 3 shows the squeezed area in cross section A sheath 53 in a particular embodiment. It can be seen that the shell 53 starting from two circumference create S3 and 85 is squeezed together, and that they are so

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is designed to be dimensionally stable in the longitudinal direction so that penetration of a drill core into the Envelope does not cause longitudinal expansion of the envelope. Preferably the sheath 53 is not elastic. Ee is for For the purposes of the invention, it is also not necessary to take an elastic material for the sheath, since the take-up and holding the core can also be carried out with a non-elastic part, provided that these are only pressed together leaves. Suitable materials are fiber-reinforced plastics, such as fiber-reinforced neoprene. It can also be Use fabric, such as fiberglass fabric. The inside of the shell 53 is preferably one-end coated with a low coefficient of friction coated, for example with polytetrafluoroethylene, us the frictional resistance when the drill core penetrates to belittle.

The shell shown in Figure 3 has two longitudinally extending stiffening cables 87 and 89, which extend along the entire envelope and ensure that the envelope narrows in the manner shown. If when attaching the cover between the Tfagteil 37 and the clamping ring 58, the sheath is pulled tight, ao that the stiffening cables 87 and 89 are tight, narrowed the shell is in any case in the way shown in FIG. presented type. The shell can of course also be arranged or designed so that it narrows in another way, in the form of a three-pointed or four-pointed star, where the stiffening ropes are longitudinally attached to the star ** to a point.

FIG. 4 shows the constricted state of another embodiment of a casing. This shell consists of a pipe, ' which consists of two elongated plates 91 and 93 of a flexible Material is made · This material is in I & aesrich- » preferably dimensionally stableThe two plates over *

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lap each other along their ends and sirfd there together connected, for example welded, and can consist of a fiber-reinforced plastic. Because of the overlap it has the shell at the areas 95 and 97 twice the thickness, so that they are in the tensioned state at these overlapping areas becomes twice as thick when narrowed.

For the operation of the drill core removal device according to the

Figures 1 and 2 can of course also be a gaseous one Use medium to narrow envelope 53. In gas drilling, air or a similar gas can be applied to the drill bit bring and then form the drilling fluid. An independent source of pressurized fluid can also be provided in the drilling tool or a pressurized fluid line for gas or a liquid separate from the soil surface to the drilling tool get lost. However, the latter is not practical with deep boreholes. When using a gas to operate the vehicle the sightings must of course be gas-tight and liquid-tight, e.g. the clamping ring 58 on the Stella 55 of the casing and the sealing ring 51. The drill bit 30 described in the exemplary embodiments is not essential to the invention, any drill bit can be used, e.g. a simple cutting edge sharpened at the bottom can be used. In the case of non-rotating drill removal devices, Instead of a diamond core bit, other bobr devices can also be used be used·

For example, FIG. 5 shows a drilling extraction device for extracting and recovering loose drill cores from the sea floor. When applying samples of deposits to the bottom of the Qaeane , which are often loose and soft, it is difficult to recover the drill core intact. The procedure for taking and moving underwater drill samples will vary depending on the equipment used * Some

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Core extractors use a simple weight extractor such as those used is shown in Figure 5. Others make use of hydraulic equipment, with a Bohrkera receiving vessel is hydraulically pressed into the seabed. Bs can too a drive device can be used to push the drill core removal container into the seabed.

In the device shown in FIG. 5, the weight 101 has pushed the drill core removal device 103 into the sea bed 108. Within the tube 103 egg ä ne zueammenquetschbare envelope 107 is provided which is formed _for example according to figure 3 and the fluid-tight manner at each end to the parts 106 and 109 is attached. A differential piston 104 is accommodated in the weight 101, the lower piston chamber being in communication with the annular chamber 111 between the sleeve 107 and the tube 103. The differential piston exerts a pressure in addition to the hydrostatic pressure, and the valve 102 allows this differential pressure to act into the annulus. A check valve 105 is also provided through which fluid flows out when the drill core expands the sleeve. This check valve is set to a higher pressure than the first-mentioned valve 102. The drilling and recovery of the drill core | takes place essentially as described above, the pressure behind the sleeve 107 serving to squeeze the lower area of the sleeve together after the drilling core removal device has been lifted from the ground.

Leg pulling-up of the device to the surface holding the Rückeohlagνentil 105 a pressure upright required $ st, üb the core in 4p shell to hold the valve draining the extent _Fluid: as the fluid pressure a | t of the core sampling device is reduced.

It can be seen from Figure 5 that a small part of the drill core

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fell from the ground when the device was pulled up, and that the casing then narrowed and closed beneath the drill core remaining in it.

The method according to the invention can also be used with other devices, e.g. in the device of Figure 5, the differential pressure can not only be realized generate by means of a differential piston 4, but also directly from the ground surface via a pressure pipe. A drill core removal device for sandy soils on cliffs can also be set up for manual operation, and that Drill pipe can be pressed into the sand by hand. Fluid nozzles can also be provided on the cutting crown to facilitate the penetration of the drill pipe into the ground.

A number of devices can be used to carry out the method of the invention, this being the case Method consists essentially in that a drill core is cut out of the formation and received in a constricting sleeve in cross-section that fluid pressure is applied to the outside of the sleeve in order to To narrow the sheath above the received drill core, the fluid pressure being kept so high that the sheath can increase in cross-section again when the drill core is picked up. In the method according to the invention in A dynamic fluid pressure drop from a point above the ground is used in rotary drilling processes of the borehole to a point near the bottom of the same, so that the dynamic fluid pressure At the bottom of the borehole with the dynamic fluid pressure, the drill core is balanced and a higher pressure is used to hold the core while it is being brought up.

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It is recorded in such a way that a fluid flow is established which creates a pressure drop in the to the Drill bit generates flowing current, whereby this fluid » flow is used as drilling fluid, and the envelope is thereby narrowed by the pressure difference of the fluidate.

The device according to the invention »approximately according to Figure 1B, can for example be provided with four check valves, such as two inlet and two outlet valves · Der lower area of the envelope, which becomes dee '| The core is intended to narrow, can also preferably be designed with a thinner wall thickness or set up in such a way be that it narrows more easily in order to ensure that the drill core is held securely.

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Claims (10)

Claims 1,) Drill core removal device for manufacturing and conveying a drill core from soil formations, with a device for separating a drill core from the formation, characterized in that a constricting device is located above the separating device Sheath (53) is arranged for receiving the drill core, that means for washing around the outer surface the envelope is provided with a fluid suppressor is this pressure height? is than the pressure within the sheath to the sheath prior to picking up the drill core to keep in the constricted state, and that an outflow device for the the outer surface of the Sheath surrounding fluid is provided, the device being such that the fluid upon entry of the drill core is pushed out into the sheath 03). 2.) Device according to claim 1, characterized in that that the shell (53) near the lower end has a narrowable area (75) having. 3 ») Device according to claim 1 or 2» thereby characterized in that the sheath (53) of is surrounded by a drill, 4 *) Device according to claim 1 bia 3, ä adureh characterized in that the outflow device has awei anti-parallel shaded and pre-tensioned check valves (49, 79) which have a relief (67) surrounding the casing (53) and a with the interior of the shell (53) in Connected room are switched on, 5.) Device according to claim 4, characterized that the sleeve (53) surrounding the tube from an outer tube (19,21) and a inner, tubular core receiving sleeve (47), which leave a fluid channel (20) free between them. 6.) Device according to claim 4 or 5, characterized in that * characterized in that the fluid channel (20) at its lower end with the interior of the shell (53) communicates. 7.) Apparatus according to claim 5 or 6, characterized in that the outer tube (19,21) is rotatable independently of the core receiving sleeve (47). 3.) Device according to claim 1 to 7, characterized in that the sheath in the longitudinal direction is less flexible than in the circumferential direction. 9.) Device according to claim 1 to 8, characterized characterized in that the sheath (53) has at least two stiffening cables in the longitudinal direction (87.89). 10.) Device according to claim 1 to 8, characterized in that the HUlIe consists of two rectangular material webs (91,93) is produced, which are connected to one another overlapping at their longitudinal edges are" 109843/1139 Blank page