CN2071701U

CN2071701U - Casing centralizer for directional well

Info

Publication number: CN2071701U
Application number: CN 90219420
Authority: CN
Inventors: 张兆银; 刘坤芳
Original assignee: Drilling-Extracting Process Inst Liaohe Petroleum Exploration Administration (
Current assignee: Drilling-Extracting Process Inst Liaohe Petroleum Exploration Administration (
Priority date: 1990-09-11
Filing date: 1990-09-11
Publication date: 1991-02-20

Abstract

The utility model discloses a casing device centralizer for directional wells which is a novel casing centralizer achieving to alter the stress structure and the stress character through altering the shape of the spring leaf of the centralizer. The utility model has the advantages of small starting-up force and large reset force and can meet requirements of casing centralization during the well cementing of the directional well, in particular to the directional well with a large slope. The utility model also has the advantages that the casing is made to descent into the oil well successfully, the resistance of the casing moving from top to bottom is small, the upwards turning back flowing resistance of grout is small, and the number of the centralizers used is smaller than conventional centralizers under the same condition. Field use indicates that the casing centralizer for directional wells of the utility model can effectively reduce the well cementing cost price of the directional well and improve the quality of well cementing.

Description

Casing centralizer for directional well

The utility model relates to a kind of casing stabbing board that uses during completion in oil, geological drilling engineering, belong to the downhole tool class.

The application of sleeve centralizer mainly is for sleeve pipe is kept in pit shaft between two parties, to obtain uniform cement sheath, reaches the purpose of high-quality well cementation.Especially in directional well, the reliable casing stabbing board of functional performance is even more important, because keep casing centralization to have bigger difficulty in common straight well, directional well well cementation.At present, both at home and abroad no matter the casing stabbing board that uses is to be used for straight well, still is used for directional well, all is the casing stabbing board of making by API SPec 10D, i.e. conventional cannula centralizer, and its main working parts spring leaf is that iso-curvature is circular-arc.This type of casing stabbing board can guarantee the casing centralization in straight well, but because of its reset force less, so for directional well, particularly changes in pitch directional well, then be difficult to satisfy corresponding requirement.In view of the above problems, usually the means to save the situation that adopts on the scene is to dwindle the spacing that casing stabbing board is laid, bring the well cementation cost to increase thus, return a series of problems such as resistance increase on up and down difficulty of sleeve pipe and the cement paste, and make cementing quality be subjected to a certain degree influence.

The purpose of this utility model be to propose a kind of have starting power little or under the constant situation of starting power the big casing stabbing board of reset force, thereby more can make the smooth G.I.H of directional well sleeve pipe, and satisfy the requirement of casing centralization, improve the cementing quality of directional well.

Casing stabbing board of the present utility model comprises the installing and locating part and sets upright part.By circle cover, change shape spring leaf, pin, upper and lower leaf of hinge and cottor pin and form.The circle cover is two semicircular body, is welded with the upper and lower hinge of assembling usefulness on the edge of semicircular body, and is chimeric with pin during work, cottor pin is housed, in case it comes off on the pin.Equidistantly on the excircle of circle cover be welded with 4 to 8 spring leafs, shape of spring plate is that the tangent arc of variable curvature and tangent straightway are formed.This geometry has fundamentally changed the geometry of traditional casing stabbing board spring leaf, has good mechanical characteristic, promptly in the process that load increases gradually, the also corresponding increase of spring leaf amount of deflection everywhere, and then spring leaf contacts with sleeve pipe gradually from fulcrum (contact point) beginning that two terminal circle overlaps, make the span between spring leaf fulcrum (contact point) dwindle gradually, the result who obtains therefrom is that the supporting capacity of spring leaf strengthens gradually.Through three-dimensional Force Calculation analysis, the increase of its supporting capacity is exponential trend and rises.If in engineering is used, need bigger reset force, then can weld two strong pads of speed symmetrically at the suitable span place of this kind spring leaf.

Casing stabbing board of the present utility model is compared with the conventional cannula centralizer, have that starting power is little, reset force is big, can satisfy the requirement placed in the middle of directional well middle sleeve with less relatively number, and the resistance of reciprocate casing is little, sleeve pipe is lowered to smoothly, to the advantages such as dynamic resistance is little of backflowing on the cement paste, can reduce the cost of directional well well cementation effectively, improve the quality of well cementation.

The utility model is described further to accompanying drawing 5 given embodiment below in conjunction with accompanying drawing 1.

Fig. 1 is the longitudinal sectional view of directional well casing stabbing board along axis;

Fig. 2 be the directional well casing stabbing board along with the transverse sectional view on the perpendicular plane of axis;

Fig. 3 is the partial view at hinge position;

Fig. 4 changes the shape spring leaf to weld the partial view at position mutually with the circle cover;

Fig. 5 is the pressure and the deflection curve schematic diagram relatively of directional well casing stabbing board and conventional cannula centralizer.

Directional well casing stabbing board among Fig. 1 to Fig. 4 changes shape spring leaf (2), 4 pins (3), 4 by 2 circle covers (1), 5 and goes up leaf of hinge (4), 4 lower jaw sheets (5), 4 cottor pins (6), 10 strong pads of speed (7) and form.Circle cover (1), pin (3), go up leaf of hinge (4) and lower jaw sheet (5), change shape spring leaf (2) and fast pad (7) by force by the spring steel manufacturing by the structural carbon steel manufacturing.Cottor pin selection standard spare changes the circular arc that is shaped as three sections disparity curvatures and two tangent linking of line segment of shape spring leaf (2), and two strong pads of speed are arranged on each spring leaf, is welded in 1/4th span places at spring leaf two ends symmetrically.

Claims

1, a kind of directional well casing stabbing board comprises installing and locating part and sets upright part, it is characterized in that: this directional well casing stabbing board by the circle cover, change shape spring leaf, pin, upper and lower leaf of hinge and cottor pin and form.

2, directional well casing stabbing board according to claim 1 is characterized in that: the shape spring leaf that changes on this centralizer is 4 to 8, and it is shaped as the tangent arc of variable curvature and tangent straightway is formed.

3, according to claim 1 and 2 described directional well casing stabbing boards, it is characterized in that: if engineering needs bigger reset force in using, the strong pad of the speed of then can burn-oning symmetrically at the suitable span place of this kind spring leaf.