Wells – Packers or plugs – With expanding anchor
Patent
1998-03-03
2000-11-07
Suchfield, George
Wells
Packers or plugs
With expanding anchor
166134, 166135, 166138, 166182, 277340, E21B 33128, E21B 33129
Patent
active
061422274
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention concerns a retrievable bridge plug.
In many situations it is necessary to isolate one or more zones in cased well. As an example, it may be necessary to isolate against fluid and pressure in an oil or gas well. In this situation, a bridge plug can be used to isolate against changes in pressure in both directions.
Such bridge plugs comprises in principle a sealing part for sealing the differential pressure, and an anchoring part for preventing movement of the bridge plug due to the pressure force. In oil and gas wells, the bridge plug will in many circumstances have to pass constrictions, for example valves and nipples (hereafter called "restrictions"), after which it becomes located in a wider casing diameter. Due to their constructions, known retrievable bridge plugs have a limitation in the expansion, which prevents use of bridge plugs in some oil and gas wells.
Known bridge plugs exist in many dimensions, adapted to the different casing dimensions where the plug is to be placed. This follows from the fact that conventional bridge plugs have a comparatively low expansion rate. The low expansion rate of conventional bridge plugs is partly due to the construction of the anchoring part, and partly due to the structure of the packing element. A common method for anchoring plugs has been to use conical slip segments which are forced out radially, between two conical pipes which are forced together axially. In this method, the expansion of the slip segments is limited by the outer diameter of the conical pipes. Without active pulling of the slip segments, they can become stuck in restrictions when being pulled out of the oil or gas well. The packing element expands when a rubber body is squeezed axially. At high pressure and great expansion, existing packing elements can creep after some time, which eventually will result in leakage over the packing element. When pulling existing bridge plugs, the elasticity of the rubber will see the packing element return to the shape it had before setting. Without active pulling of the packing element, a deformed packing element may lead to difficulties in pulling the bridge plug out of the well, because it can become stuck in restrictions.
SUMMARY OF THE INVENTION
It is thus an object of the invention to provide a retrievable bridge plug which has a high expansion rate, may be anchored in a secure way in the well, and cover an expansion area which until now has demanded a number of bridge plugs with different setting diameter.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following, the invention will be described further by means of examples of embodiments and with reference to enclosed drawings, where
FIG. 1 shows a partly axially sectioned bridge plug according to the present invention, during entrance in a cased well,
FIG. 2 shows the partly axially sectioned bridge plug from FIG. 1, in expanded and anchored condition,
FIG. 3 shows the partly axially sectioned bridge plug of FIG. 1, drawn down and detached, ready for retrieving out of the cased well,
FIG. 4 shows an axial half sectioned packing element of the bridge plug of FIG. 1, in a down-drawn condition,
FIG. 5 shows a partly sectioned view of the packing element from FIG. 4, where cord layers from the different packing elements are depicted,
FIG. 6 shows the axial half sectioned packing element from FIG. 4, in expanded condition,
FIG. 7 shows an axial half sectioned packing element composed of a sealing packing element having two supporting packing elements on each side, where the supporting packing elements are expanded up to their expanded diameters,
FIG. 8 shows an axial half section of a packing element comprising two sealing packing elements which have a common supporting point in the middle, and supporting packing elements on each side,
FIG. 9 shows a half section of the front part of the bridge plug of FIG. 1, where the slip segments of the anchoring means are drawn down,
FIG. 10 shows a half section of drawing springs in the slip segments, taken along the line X-
REFERENCES:
patent: 2612953 (1952-10-01), Morgan et al.
patent: 3057406 (1962-10-01), Patterson et al.
patent: 3097696 (1963-07-01), Orr
patent: 3570596 (1971-03-01), Young
patent: 3666010 (1972-05-01), Harris
patent: 3776561 (1973-12-01), Haney
patent: 4284137 (1981-08-01), Taylor
patent: 5701959 (1997-12-01), Hushbeck et al.
Andersen Frode
Hiorth Epen
Pedersen Dag Ravn
Bronnteknologiutvikling AS
Maritime Well Service AS
Suchfield George
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