How to make a continuous core sample ?

Wireline drilling, also known as diamond coring, is a specialized drilling technique that is mainly used in the mineral exploration industry. It involves the use of a diamond-impregnated drill bit that is attached to a wireline cable. The drill bit rotates at high speeds and cuts through the earth's crust, allowing geologists to collect core samples.

One of the key differences between wireline drilling and other drilling methods is the ability to retrieve intact core samples. Unlike other drilling methods, wireline drilling allows for the extraction of long, continuous cylindrical samples of the earth's subsurface. These samples provide valuable information about the composition, structure, and properties of the geological formations being explored.

Wireline drilling is also known for its high drilling rate and efficiency. The diamond-impregnated drill bit used in wireline drilling is exceptionally hard and can penetrate even the toughest formations. This allows for faster drilling and reduces the overall time required to complete a drilling project. Additionally, the wireline cable used in this method is relatively thin, which minimizes drilling disturbances and ensures a more accurate representation of the subsurface conditions.

The wireline coring system was developed to increase production in holes where a continuous core sample is required.

This is achieved using an inner tube with a core barrel head incorporated with latches that lock into the adaptor and locking couplings at the top of the core barrel outer tube. The inner tube is lowered into the outer barrel through constant internal bore drill tubes (drill rods). It then locks in position by means of the latching mechanism but is able to rotate through the bearing section incorporated in the core barrel head. At the end of the core run a recovery tool (overshot) is lowered through the drill string on a wireline. This locates on the top of the inner tube and retracts the latches when the wireline is hoisted. The inner tube and core can then be lifted to the surface.

This technique has considerable advantages over conventional coring as the drill string does not have to be run in and out of the hole at the end of each core run. The wireline coring system has become the favoured method of coring; particularly in deeper holes, although there is still a great deal of conventional coring carried out.

Wireline core drilling is a system that drills and collects a core (cylindrical) sample in the state it is found,The system known as ‘wireline coring’ is used, ie a diamond impregnated (hollow) core bit is used which cuts until the core barrel is full. Drilling Mud / Cutting oil cools/lubricates bit and acts as medium for lifting cuttings to surface.

Sinocoredrill provides Core Drilling in the following sizes:

PQ     Ø 85.0 mm

PQ3    Ø 83.0 mm

HQ     Ø 63.5 mm

HQ3   Ø 61.1 mm

NQ2   Ø 50.5 mm

NQ    Ø 47.6 mm

BQ    Ø 34.4 mm

Wireline core drilling method can take out the core without having all the drill rod out of the borehole, which can have high drilling efficiency and low labor intensity. Therefore it is the most popular among all core drilling method currently.