Classifications

• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B33/00—Sealing or packing boreholes or wells
  • E21B33/10—Sealing or packing boreholes or wells in the borehole
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
  • E21B17/14—Casing shoes for the protection of the bottom of the casing
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B33/00—Sealing or packing boreholes or wells
  • E21B33/10—Sealing or packing boreholes or wells in the borehole
  • E21B33/12—Packers; Plugs
  • E21B33/1208—Packers; Plugs characterised by the construction of the sealing or packing means
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B7/00—Special methods or apparatus for drilling
  • E21B7/20—Driving or forcing casings or pipes into boreholes, e.g. sinking; Simultaneously drilling and casing boreholes

Definitions

• the subject invention concerns a method and a device in rock drilling wherein a casing provided with a rigid front end portion is lowered concurrently with the drilling to seal said casing front end portion from the wall of the drilled hole.
• the casing may be pulled down through the drill hole concurrently with the very drilling thereof.
• One type of such simultaneous drilling and pulling down of the casing is the method known as the ODEX Method. According to this, the casing which could be made from e.g. a plastics material, is fitted at its lower end with an end sleeve of metal or some other heavier material.
• the end sleeve may be attached to the casing by means of rivets or screws when the casing is made of plastics. If the casing is made of metal, the end sleeve could also be attached thereto by means of welding. In accordance with the prior-art method, the end sleeve is formed at its top with a shoulder projecting beyond the inner wall of the casing against which abuts a portion of a drill tool rotating inside the casing interior.
• a central drill bit as well as a so called reamer project below the lower end of the end slevee, and upon rotation of the drill in one direction the reamer is forced to expand in the radial direction in such a manner that it becomes possible to perform drilling operations below the end sleeve for reaming a drill hole the diameter of which exceeds that of the casing. Because of the abutment of the drill body against the end sleeve shoulder the casing is pulled downwards simultaneously with the drilling at the pace of the drilling operations.
• the drill tool When the casing reaches the desired depth, the drill tool is rotated in the opposite direction, whereby the reamer is retracted in the radial direction in such a manner that the drill tool together with the drill bit may be pulled upwards in the interior of the casing.
• water and drill cuttings are fed upwards, mainly in the interior of the casing, but material loosened from the rock is advanced upwards also in the gap between the casing and the drill hole wall.
• the main purpose of the invention is to provide a method and a device whereby these disadvantages are eliminated, i.e. an arrangement which allows the casing to be driven down into the drill hole during the drilling without encountering much resistance and, upon completed drilling, provides efficient sealing between the casing and the drill hole.
• This purpose is achieved in that in one or several external peripheral grooves formed in the end part of the casing, annular members are lodged, said members being of a material which expand with delay when moistened.
• the expandable material may be coated with a delay layer which only slowly dissolves upon its contact with liquids, thus preventing or at least counter-acting the expansion of the material during the time required to effect the drilling including the simultaneous lowering o the casing.
• the peripheral grooves in the end portio of the casing are formed with walls presenting an obliquely upwards-directed slope towards the drill hole wall.
• thi arrangement likewise creates an area of abutment against the drill hole wall that is comparatively extensive vertically in relation to the width of the grooves.
• the risk of drill cuttings and other material penetrating into the grooves and in doing so impairing th subsequent sealing effect is reduced.
• Fig. 1 illustrates the lower portion of a drilling tool while reaming a drill hole to allow positioning therein of a casing
• Fig. 2 illustrates the same part of the drill hole with a casing in position and the drill tool being retracted through the casing;
• Fig. 3 illustrates the casing in sealing position against the corresponding drill hole wall
• Fig. 4 illustrates on a smaller scale the extension of the casing through the upper fissured rock strata and the further extension downwards of the drill hole through the rock.
• Figs. 1 and 2 illustrate a drilling operation including simultaneous lowering of a casing 1 in accord ⁇ ance with the ODEX method referred to previously.
• the casing 1 could for instance be made from steel but very often it is made from a softer material, such as a plastics material.
• Reference numeral 2 designates an end sleeve the upper portion of which is inserted into the interior of the casing 1 and which preferably is attached to the casing by means of screws, rivets or the like.
• the end sleeve 2 could of course also be welded to the casing.
• the sleeve 2 is formed with a number of peripheral grooves 3 the side walls of which, in accordance with the embodiment shown, extend obliquely upwards, towards the hole wall 4.
• an annular member 5 is inserted, the material of said members preferably being a rubber material of a kind which expands when moistened.
• the expandable material of the annular members preferably consists of a chloroprene material, for instance a material of the kind marketed under the trade name "Hydrotight".
• On the expandable material of the annular members could be applied a surface coating which is slowly dissolved by liquid for the purpose of delaying the contact liquid/expandable material and thus also delaying its expansion effect.
• the annular members 5 are dimensioned so as to be completely or at least almost completely housed inside the grooves 3.
• the upper end edge 6 of the end sleeve 2 forms an upwardly directed shoulder against which abuts a downwardly facing collar 7 on a guide member 8 on the drilling tool.
• the guide member 8 serves as a mounting piece on which a shaft 9 is fitted, the upper end of said shaft being connected above the drill hole to a drive unit, not illustrated in the drawings.
• the drilling tool is provided with a drill head 10 above which a reamer 11 is disposed.
• the reamer 11 is mounted on the shaft 9 in such a manner between the drill head 10 and the mounting sleeve 8 that upon its rotation in one direction it is expanded radially and is maintained in this position, i.e. the position illustrated in Fig. 1, whereas upon its rotation in the opposite direction it is retracted, assuming a smaller external diameter size than the inner diameter size of the end sleeve 2. In the latter position the entire tool may be pulled upwards through the sleeve 2 and the drill hole as illustrated in Fig. 2. During drilling operations, the drill head 10 including the reamer 11 are driven into the rock.
• the reamer 11 first widens the drill hole below the casing and the end sleeve 2 to a diameter size exceeding the diameter of the latter by a suitable clearance a which preferably is sufficiently large to allow the casing 1, during the drilling operation, to be lowered inside the drill hole without encountering unnecessary resistance. Drill cuttings loosened by the drill head 10 and the reamer 11 are forced upwards together with liquid, if any, through a longitudinal groove 12 formed in the peripheral surface of the mounting sleeve 8, into the space within the casing 1, to be further conveyed upwards through the latter. During the drilling, some drill cuttings also flow upwards in the gap a between the end sleeve 2 and the wall of the drill hole 4.
• the material of the annular members 5 is chosen to ensure that the expansion thereof is delayed until the drilling operation referred to above is completed. Should any water exist in the excavated drill hole the expansion of the annular members 5 will occur automatically. In case no water yet exists in the drill hole water is supplied through the drill hole. The presence of water makes the annular members expand with delayed effect and assume the condition illustrated in Fig. 3, wherein the expanded annular members abut tightly against the wall of the drill hole 4, thus forming efficient seals. Owing to the oblique configuration of the grooves 3 the annular members are given a vertically expanded surface of contact against the drill hole wall 4 and they efficiently follow the wall contour. At the same time, the major expansion is directed upwards, which means that the casing is retained in position inside the casing as if by barbs.
• a drilling tool which preferably corresponds to the lower part 14 of the drill hole already excavated, i.e. to approximately the interior of the end sleeve 2.
• This continued drilling operation may be effected immediately, or simultaneously with or after the expansion of the annular sealing members.
• the hole could be drilled to a smaller diameter size.
• any cracks 15 occurring in the rock are spanned by the casing the lower end of which is sealed off against the rock. In this manner surface water and other pollutants are efficiently prevented from penetrating into the drilling hole which thus may be kept clean for a very lon time.

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• Engineering & Computer Science (AREA)
• Geology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Mining & Mineral Resources (AREA)
• Environmental & Geological Engineering (AREA)
• Fluid Mechanics (AREA)
• Physics & Mathematics (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Mechanical Engineering (AREA)
• Earth Drilling (AREA)
• Drilling Tools (AREA)
• Drilling And Boring (AREA)

Applications Claiming Priority (3)

Publications (2)

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ID=20385571

Family Applications (1)

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Cited By (3)

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• 1992
  • 1992-03-09 SE SE9200730A patent/SE9200730L/ not_active IP Right Cessation
• 1993
  • 1993-02-09 WO PCT/SE1993/000089 patent/WO1993018274A1/en active IP Right Grant
  • 1993-02-09 AT AT93906918T patent/ATE152210T1/de not_active IP Right Cessation
  • 1993-02-09 DE DE69310159T patent/DE69310159D1/de not_active Expired - Lifetime
  • 1993-02-09 EP EP93906918A patent/EP0629259B1/de not_active Expired - Lifetime

Non-Patent Citations (1)

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