Principle and schematic diagram of drilling coring

The coring is completed by a coring barrel, and the traditional coring barrel is connected at the bottom of the drill pipe near the drill bit; After the coring cutting head cuts into the formation, the coring barrel can be used for continuous coring and then taken out of the drill pipe.

Only when the cementation and drillability of formation rocks are good, can medium-long barrel coring be carried out. The purpose of medium-long barrel coring is to increase the coring footage of single barrel as much as possible on the premise of ensuring high core recovery rate, so as to greatly improve the coring recovery rate and reduce the coring cost.

Extended data:

In the later stage of sandstone oilfield development, in order to accurately obtain the data of reservoir fluid saturation, reservoir pressure, relative humidity and reservoir conditions at that time, formulate a reasonable development adjustment scheme and improve the ultimate oil recovery of the oilfield, the cores that maintain the integrity of reservoir fluid are drilled under the condition of water-based drilling fluid by using pressure-keeping sealed coring tools and sealing fluids.

Drill a core that is not polluted by drilling fluid freely, and keep the reservoir pressure under the bottom hole conditions at that time. This kind of coring equipment and technology are complex and costly, and it is suitable for soft, medium and hard formations.

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