Geobore S is particularly effective when high quality cores are required in clay, sand or loose⁄weak formations. When used by suitably trained staff it can be used to obtain high quality cores in a wide range of geological conditions.
The inner tube assembly latches inside the outer core barrel is lifted to the surface by a retrieval device connected to a wireline cable. The wireline retrieval method greatly improves production rates compared to conventional coring method but also leaves the borehole fully cased at all times ensuring borehole stability in sensitive geology.
Geobore S can be used with a wide range of flushing methods and bit types to improve core quality and penetration rates:
Method 1: As standard for coring medium to hard formations. All bit types can be used depending on geology.
Method 2: For coring in soft to very soft formations .Mainly TC-set bits are used and the bit consists of two parts - pilot and reamer.
Method 3: For coring in very soft or loose formations. The bits are as method 2 but the core lifter case is extended to run 25mm in front of the bit.
Method 4: Full hole drilling assembly, this is an attachment that replaces the inner tube for non coring purposes.
both are heavy-duty wireline core barrel enabling 102 mm (4″) diameter cores to be taken in a simple and cost-effective manner. It is designed specifically for air-flush, but foam, polymer and water flush can also be used.
These core barrels have been proven to 2500 metres in depth, with full float capacity, or a dry hole lowering device. With a 6 mm all-round clearance between the outer and inner tubes, full advantage can be taken of both air and foam flush in soft formations.
The core barrels can be used with or without plastic coreliner tubes with the same core lifter and bit setting. The barrel accepts the Craelius SK6L type core bit, or our own equivalent, with a set O.D. of 146 mm and set I.D. of 102 mm. The barrels are rotated with either SK6L 140 mm drill rods or by using good quality PW casing as the drill rod.
The core barrel heads are attached directly onto the inner tube and consists of three main parts: the latch assembly, which locks into the locking coupling of the outer tube, the bearing housing, and the inner tube bung. The inner tube bung incorporates a series of "Belleville" springs to allow the core to be broken easily when pulling back on the inner tube, and a float valve that allows the inner tube to be dropped into a wet hole and to control the rate of descent.
Main Features of booth types of core barrels
Outer tube assembly
1. Drill rod coupling
2. Locking coupling
3. Landing ring
4. Adaptor coupling
5. Inner tube
6. Blank reaming shell
7. Core bit (not included)
Inner tube assembly
8. Lifting spear
9. Upper stabilizer
11. Lower stabilizer
12. Bearing assembly
13. Inner tube bung
14. Outer tube
15. Plastic "coreliner"
16. Lifter case