Boring or penetrating the earth – With tool shaft detail – Helix or helically arranged structure
Patent
1994-11-28
1997-07-22
Dang, Hoang C.
Boring or penetrating the earth
With tool shaft detail
Helix or helically arranged structure
1662413, 1753253, E21B 1710
Patent
active
056496036
DESCRIPTION:
BRIEF SUMMARY
This invention relates to downhole tools, and relates more particularly but not exclusively to downhole tools in the form of well-drilling tools which facilitate the drilling of wells which are substantially non-vertical.
BACKGROUND
As oil and gas reserves become scarcer or depleted, methods for more efficient production have to be developed.
In recent years horizontal drilling has proved to enhance greatly the rate of production from wells producing in tight or depleted formation. Tight formations typically are hydrocarbon-bearing formations with poor permeability, such as the Austin Chalk in the United States and the Danian Chalk in the Danish Sector of the North Sea.
In these tight formations oil production rates have dropped rapidly when conventional wells have been drilled. This is due to the small section of producing formation open to the well bore.
However when the well bore has been drilled horizontally through the oil producing zones, the producing section of the hole is greatly extended resulting in dramatic increases in production. This has also proved to be effective in depleted formations which have been produced for some years and have dropped in production output.
However, horizontal drilling has many inherent difficulties. In broad terms the difficulties include the following factors: increasing hole angle (angular displacement from vertical) and length of the horizontal section, push the drillpipe along the horizontal section thereby increasing the fatigue stresses in the drillpipe located on the bend between the two sections,
and as difficulties in applying weight and torque affect the ROP ("rate of progress" in deepening/lengthening of the well).
PRIOR ART
Conventional stabilisers used in assemblies for horizontal drilling do little to resolve the above problems. Conventional stabilisers have fixed blades which normally are spiralled to distribute well contact area whilst still allowing fluid bypass. Conventional stabilisers also generate quite considerable back torque and resistance to forward motion although they do centralise the drilling assembly and play an important role in directional control of the hole.
A number of attempts have been made to reduce friction by the development of rolling element stabilisers. A recent one of these stabiliser tools (described in published European Patent Application EP0333450-A1) used freely rotating balls set into the stabiliser blades which addressed points (i) and (ii) above. initially the tool was well received by the oil industry as there was a real need to resolve the downhole torque problems. Unfortunately the tool proved to have problems with the balls packing off and locking with cutting debris. This considerably reduced the market interest in this tool.
Another known form of rolling element stabiliser is based on rollers mounted on respective axes which are each parallel to the longitudinal axis of the stabiliser and hence parallel to the longitudinal axis of the drillstring and of the well drilled thereby. Examples of this form of roller stabiliser are described in U.S. Pat. 3907048 and United Kingdom Patent Specification GB271839. The functional effect of this form of roller stabiliser is to reduce rotational friction (by reason of the rolling support of the stabiliser against the bore of the well or well casing), but to have a neutral longitudinal effect (by reason of the parallelism of the roller axes with respect to the longitudinal axis of the stabiliser and the drillstring incorporating the stabiliser).
A still further form of rolling element stabiliser which purports to reduce both rotational and longitudinal friction is described in U.S. Pat. No. 1,913,365. This further form of roller stabiliser essentially comprises a collar which is rotatably mounted on the exterior of a drillstring by two rows of vertical-axis rollers, i.e. rollers whose respective axes are each parallel to and radially offset from the longitudinal axis of the drillstring. (These vertical-axis rollers are externally spherically shaped, and therefore sup
REFERENCES:
patent: 1750628 (1930-03-01), Crum
patent: 1848404 (1932-03-01), Abegg
patent: 2168017 (1939-08-01), Hammer
patent: 4040495 (1977-08-01), Kellner et al.
patent: 4190123 (1980-02-01), Roddy
patent: 4365678 (1982-12-01), Fitch
patent: 4465146 (1984-08-01), Fitch
patent: 4880066 (1989-11-01), Steiginga et al.
patent: 4958692 (1990-09-01), Anderson
patent: 5033558 (1991-07-01), Russo et al.
Abercrombie Simpson Neil Andrew
Coey Paul Raymond
Astec Developments Limited
Dang Hoang C.
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