Methods and apparatus for drilling open hole

Abstract

Methods of drilling open hole and apparatus for achieving same are described. One apparatus comprises a pressure control component strategically positionable in or above a wellbore to isolate downhole pressure while drilling open hole, the pressure control component comprising a rotational drive member effective to rotate a tubular member while drilling open hole. This abstract allows a searcher or other reader to quickly ascertain the subject matter of the disclosure. It will not be used to interpret or limit the scope or meaning of the claims.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of Invention [0002] The present invention involves use of a snubbing apparatus to drill open hole. More particularly, the present invention involves use of a snubbing apparatus to drill open hole in underbalanced and managed pressure situations. [0003] 2. Related Art [0004] Heretofore, various configurations of drilling rigs have been proposed. The basic purpose of all such rigs has been the same: to drill a hole (a well or wellbore) that taps into an oil or gas reservoir. Subsequently, crude oil and / or natural gas are extracted from the tapped reservoir and processed into usable forms, such as gasoline and heating oil. [0005] In oil and gas operations, pipes or tubular members are usually run in or pulled out of a well using conventional drilling or workover rigs or a snubbing apparatus. Workover rigs are effectively small drilling rigs having a derrick and drawworks. Although less costly and easier to employ than full sized drilling rigs...

AI Technical Summary

Benefits of technology

[0036] In accordance with the present invention, methods and apparatus are descr

Problems solved by technology

Although less costly and easier to employ than full sized drilling rigs, workover units can still be quite costly.

Most snubbing units, however, do not provide a method for imposing torque on a held pipe or tubular member (e.g., the snubbing unit described in U.S. Pat. No. 4,085,796); other snubbing units do (e.g., the snubbing apparatus described in U.S. Pat. No. 5,746,276).

Conventionally, drilling is carried out in an overbalanced condition, a condition in which fluid pressure in a wellbore is greater than fluid pressure in the formation surrounding the wellbore.

Mud (a fluid circulated in a well) is used in conventional drilling to ensure that hydrocarbons are not produced during drilling, which can be unsafe.

Increased penetration rates are also often observed in wells drilled underbalanced.

Underbalanced drilling is, however, initially more costly than overbalanced drilling, and to maximize benefits extreme care must be taken to keep drilling and completion operations underbalanced at all times.

In MPD, hydrocarbon production is not planned for or is limited in volume.

These patents do mention open hole drilling and completion, and that snubbing units are less expensive; however, they do not teach or suggest use of snubbing units for drilling open hole: “In order to minimize cost [of drilling and completion], several techniques have been employed with varying degrees of success.

Thus, rather than completing the well with the more expensive rig, a less expensive rig is utilized.” (column 2, lines 22-30) These passages are not enough to teach or suggest using a snubbing apparatus for drilling open hole.

However, from the disclosure it appears that the snubbing apparatus is not being used to drill, but only being used in the traditional sense to control pressure in an underbalanced situation.

The underbalanced drilling system may typically comprise elements such as a rotating blow out preventer and drilling recovery system.

This patent teaches away from using a snubbing apparatus for removing drill string, and does not disclose or suggest using a snubbing apparatus for drilling open hole.

However, the snubbing apparatus takes considerable time to rig up, requires considerable additional time while tripping the well, and then requires considerable additional time to rig down.

Thus, the cost of tripping the drill string can be quite considerable due to the rig time costs and snubbing apparatus costs.

This procedure then, while effective and safe, increases drilling costs considerably.”

This patent teaches away from using a snubbing apparatus, and does not teach or suggest using a snubbing apparatus to drill open hole.

This procedure is expensive and complicated.

In the zones invaded by these bottom-hole well-bore liquids while stripping through the snubbing apparatus, the rock permeability to the formation fluids may be severely damaged as described above.”

However, the snubbing unit is used only when the drilling or completion assembly is being tripped in and out of the hole.

These passages do not teach or suggest using a snubbing unit for drilling open hole.

Images