Boring or penetrating the earth – Processes – Boring curved or redirected bores
Reexamination Certificate
2000-01-10
2001-12-04
Pezzuto, Robert E. (Department: 3671)
Boring or penetrating the earth
Processes
Boring curved or redirected bores
C175S078000, C166S117500, C166S313000
Reexamination Certificate
active
06325164
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a drilling device and a method of creating branches in a bore hole drilled in unstable (unconsolidated) rock. The laying of network lines in the area of a road/street entails the construction of large main lines or network line routes from which small-diameter subsidiary lines branch off during the simultaneous construction of house service lines.
2. Description of the Related Art
On busy roads, digging up roads in order to lay house service lines or construction branch trenches in the road area results in considerable obstructions to traffic and particularly leads to statically adverse encroachments as a result of subsequent subsidence phenomena or the penetration of moisture in the transition zone between the original and repaired road surfaces, running the risk of frost damage. Furthermore, the house service connections in the area of water distribution, natural-gas distribution and for laying electricity or telecommunications lines must each be performed independently of one another, thereby worsening the damage to roads and obstructions to traffic.
In the field of drilling for mineral oil, the development of the North Sea and the use of expensive oil rigs made it necessary to execute a plurality of bores from one of the oil rigs. This “multilateral drilling” therefore became a standard concept in the offshore sector. Whereas the first multilateral bores continued to use adjacent entry bore holes that were each nevertheless independent, techniques were devised on the basis of this practice that used a single entry bore hole from which a plurality of deflected bores are executed. In the “whipstock” technique, use is made of the lateral horizontal deflections deflected by the entry bore in order to pass through hydrocarbon deposits horizontally.
The application of the whipstock technique is performed using an alignable, high-precision whipstock and a drilling system including a screw-type motor and at least two hinge points or titanium screw-type motors without hinge points and stabilizers in the drill rods. There must be a solid bore-hole wall in the area of the branch; this wall may have to be cemented and frequently stabilized by insertion of a branch fitting, too.
The bore-hole branch techniques known in the prior art have so far only been implemented on a large scale in the extraction of oil, petroleum gas or natural gas and have so far been performed either in the rock or in the area of pre-concreted branch sites. The known techniques are therefore inapplicable for the construction of bore-hole branches in the area of network lines in the road area because unconsolidated rock is present here.
SUMMARY OF THE INVENTION
The invention is therefore based on the development of a device and method for creating bore-hole branches that can be implemented in unconsolidated rock.
The invention is based on the use of a pilot drill head whose progression or movement is fully controlled and includes drill rods attached thereto such that the pilot drill head has an opening on its periphery and a deflection part therein. Outlet openings are also provided for a reinforcing-action drill suspension. Within the drill rods of the pilot drill head, an inner drill head is movable in the longitudinal direction and can be deflected by a deflection part out of the pilot drill head's path. Conveying a drill suspension, which exhibits lubricating and reinforcing action, out of the outlet openings in the pilot drill head causes the unconsolidated rock surrounding the pilot bore to be locally consolidated so as to stabilize the branch site.
The use of a pilot drill head whose advance or movement is fully controlled allows the pilot bore to follow the desired route path of the main supply lines and enables the inner drill head to construct the bores for the house service lines after deflection out of the pilot drill head path.
According to a preferred embodiment, the progression or movement of the inner drill head is fully controlled. The advantage thereof is that the desired laying path can be created in the case of complicated routes. It also is possible to drill the connecting lines accurately when laying house service lines to buildings located further away from the network line route.
The opening in the pilot drill head can preferably be closed by a movable, e.g. rotatable, cover member. The provision of such a cover member prevents rock from entering the opening during the advance of the pilot drill head and from wedging therein. Such a provision also prevents a reinforcing-action drill suspension from possibly penetrating the pilot drill head during the subsequent conveyance of this suspension out of the drill head nozzles, thereby making it impossible for a considerably consolidated structure to be formed inside the pilot drill head.
According to a preferred embodiment, the deflection part within the pilot drill head and the opening mated with the deflection part are systematically rotatable on the longitudinal axis of the pilot drill head. This has the advantage that any directions of the branching bore can be created relative to the pilot drill head's longitudinal axis.
According to a further preferred embodiment of the invention, additional lateral nozzles are located on the periphery of the drill head, whereby these lateral nozzles can be activated by remote control. An advantage of such lateral nozzles is that the reinforcing-action drill suspension can be systematically conveyed into the unconsolidated rock surrounding the pilot bore. Another advantage is that the emergence of the drill suspension also only occurs if the pilot drill head is located in the area of a planned branch site. Another advantage is that the fluid emerging out of the drill head nozzles at the front end of the drill head can be systematically chosen to the extent that the surrounding structure is loosened, thus allowing the pilot drill head to be advanced rapidly. Meanwhile, the reinforcing-action drill suspension is chosen only with regard to the desired consolidation of unconsolidated rock and emerges out of the lateral nozzles on the periphery of the drill head only when required.
The deflection part preferably includes an angled, groove-shaped surface. The provision of an angled surface, which may also be bent in the shape of a guide ramp, allows the inner drill head and inner drill rods to be conveniently deflected out of the path of the existing pilot drill head. The extra provision of grooves confers lateral guidance on the movement of the inner drill head and the inner drill rods after a branching off of the inner drill head has taken place.
According to a preferred embodiment, the inner drill head includes a plurality of hinge points that enable a narrow drilling radius.
According to a preferred embodiment of the method of the invention, the inner drill head can be advanced as far as a target area and a subsidiary line can be attached to the rods of the inner drill head, whereupon the rods are retracted right into the vicinity of the pilot bore. This procedural step is advantageous to the extent that not only are the bores necessary for construction of connecting lines created, but the retraction of the inner drill head rods is also used to insert the desired subsidiary line.
The method also preferably includes the steps of inserting a main line into the pilot bore and of creating pipe branches by sectionally drilling the main line and connecting the subsidiary line to the main line. These additional procedural steps enable complete laying of both the main line in the network line route and the branching house service lines. By drilling the main line, in each case, in the area of the subsidiary lines located close to the main line, the main line and the subsidiary line located in the area of a bore can be joined together by suitable measures.
The connection of the subsidiary line to the main line is preferably effected by placing a pipe connection over the subsidiary line and tightly attaching the subsidiary
FlowTex Technologie GmbH & Co., KG
Pezzuto Robert E.
Taylor & Aust P.C.
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