Combined Drilling

Combined Drilling


the combination or alternation at intervals of different methods and types of drilling (percussion and rotary drilling, coreless and core drilling, and so on) in sinking a borehole. The main advantage of combined drilling over any other drilling method is that it permits efficient use of several types of drilling, each of which is most favorable under certain drilling and geological conditions, during the sinking of a hole.

The combined method is often used for drilling shallow holes during geological engineering studies, surveying and prospecting work, and prospecting for nonmetallic building materials, because the rock and soils near the surface of the earth are particularly diverse in their physical and mechanical properties. Portable and self-propelled rigs that make possible the combination of several drilling methods are manufactured for sinking such holes (usually to depths of 40–50 m). For detailed deep-hole prospecting for many minerals, coreless drilling is often combined with core drilling. In this case thick rock series having no mineral content are drilled through at high speed by the coreless method, and the rock strata with mineral content are drilled through by the core method, with careful recovery of the core. The combined drilling method is used for deep gas and oil drilling: thick viscous-plastic rock strata are drilled by the rotary method, but hard rock is drilled by means of turbodrills and electrodrills.


Vozdvizhenskii, B. I., A. K. Sidorenko, and A. L. Skorniakov. Sovremennye sposoby bureniia skvazhin. Moscow, 1970.


References in periodicals archive ?
Mason tools has lost work because they have been unable to supply this type of combined drilling tool.
This work will proceed through the necessary refinement to the development of combined drilling targets as rapidly as possible.
The Company estimates that the combined drilling cost of both wells will be approximately $15 million (net to the Company's interest).
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For the Company's combined drilling operations, revenues were $150.
A reconciliation of combined Drilling Services Segment margin and Production Services Segment margin to net income (loss) as reported is included in the tables to this news release.
Combined drilling and testing time for these first two wells is estimated to be 100 days.
Clyde Smith, the Company's contracted geologist, has recommended that the combined drilling depth be increased from 1200 feet to 1400 feet.
The combined drilling effort in 2005 will add an estimated 90,000 feet of new resource definition to a database that already includes information from 185,000 feet of earlier drilling on the NorthMet deposit.
The Company's combined drilling operations achieved increases in revenues, gross margin and gross margin as a percentage of revenues for the 2014 second quarter, compared with 2014 first quarter results.
The drill program further tested the target area, which remains open laterally, and was conducted using a combined drilling method where holes were drilled from surface to near the target horizon with a less expensive rotary drill.
Our combined drilling programs include several high-impact projects that are currently underway.

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