Wells – Processes – Vibrating the earth or material in or being placed in the...
Reexamination Certificate
2002-05-08
2004-04-27
Walker, Zakiya (Department: 3672)
Wells
Processes
Vibrating the earth or material in or being placed in the...
C166S177600, C166S286000
Reexamination Certificate
active
06725923
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to boreholes technologies in connection with drilling and exploitation of wells and can be particularly used to intensify inflow of fluids from ambient rock, cleaning of the wells screens, and also to free stuck pipes in well and improving quality of cementing of casing pipes in wells.
2. Prior Art
A method and device are known for exciting transverse oscillations of pipes in wells via placing in the main column string of an additional column of smaller diameter, which is equipped along its perimeter with edges of equal size. When rotating that additional column its edges produce hits causing the transverse vibrations of the main column string (SU 734386, May 15, 1980).
General shortcomings inherent to this known technical solution are the following:
1. Big size of equipment to implement the method;
2. Insufficient effectiveness because of high level of energy consumption and low repetition rate of produced hits;
3. Inability to produce oscillations in a liquid filling a well, i.e. to effect the rock in the zone of column perforation via the liquid (only agitating of the liquid occurs).
Also a method is known for exciting transverse oscillations of a pipe string in a well comprising placement into a pipe string filled with a liquid of a hammer on a flexible suspension support and exciting of its radial periodical oscillations followed by transferring of transverse high frequency hits on the pipe string (U.S. Pat. No. 5,273,114; Dec. 15, 1993), which method is the closest technical solution to the proposed one.
A device is known for exciting transverse oscillations of a pipe string in a well comprising a string of pipes partially or fully filled with a liquid, a hammer placed in the said pipe string and a limiter of axial motion of the said hammer made in a form of a flexible suspension support, one end of which is connected with the said hammer (U.S. Pat. No. 5,273,114; Dec. 15, 1993).
The following can be referred to as shortcomings of the said solutions:
1. Source of vibrations—hammer is connected to the point located in the pipe string. Because of that the transverse oscillations that are locally excited in the column are attenuated as distance is increased from this location;
2. The hammer operates only if a liquid is pumped through while the conditions can take place in a well when it is not possible to circulate liquid, for example, during a stuck pipe when running a casing pipe or after injecting and squeezing of a cement or during effecting on a productive rock when it is not advisable to fill the well with a liquid to avoid killing of oil inflow, and in some other cases;
3. Possibilities to control the parameters of oscillations are believed to be insufficient;
4. Necessity to employ special pumping equipment with high consumption of power.
SUMMARY OF THE INVENTION
Technical effect, what is the eliminating of the said shortcomings, can be achieved by that in the method for exciting of transverse oscillations of a pipe string comprising a placing of a hammer into a pipe string filled with a liquid and exciting of its radial periodic vibrations and transfer of transverse hits to the said pipe string, wherein the said hammer is made to provide ratio of its maximal cross-section to inner transverse cross-section of the string within the limits of 0.9-0.98 and it is placed into the pipe string on a flexible suspension support, and radial periodical vibrations of the hammer are produced due to its axial motion within the said string at a speed to be selected from a condition of a pulling force applicable on a support which is determined experimentally.
Additionally:
Strength of hits transferred to the string is controlled by a weight suspended under the hammer on a flexible suspension support;
Strength of hits transferred to the string is controlled by a number of hammers placed under each other on a flexible suspension supports;
Strength of hits transferred to the string is controlled by viscosity of a liquid filling the pipe string;
Strength of hits transferred to the string is controlled via different filling of the liquid in the pipe string with gaseous phase;
Strength and repetition rate of hits transferred to the string are controlled by acceleration of the hammer motion;
Strength and repetition rate of hits transferred to the string are controlled due to parametric gain of oscillations of the hammer;
Strength and repetition rate of hits transferred to the string are controlled by changing of a clearance between the hammer and internal transverse cross-section of the pipe string;
Strength and repetition rate of hits transferred to the string are controlled by variation of shape of the hammers;
Strength and repetition rate of hits transferred to the string are controlled by changing of a distance between the hammers in the garland.
Also:
The hammer is being moved with such a speed that result in rupture of continuity of column of a liquid filling the pipe string.
Regime of oscillations of the hammer is controlled at mouth of the well by tension of the flexible suspension support.
In the proposed device the required technical effect is achieved due to that in this device comprising a string of pipes partially or fully filled with a liquid, a hammer placed in the said pipe string and a limiter of axial motion of the said hammer, wherein the said hammer is made to provide ratio of its maximal cross-section to inner transverse cross-section of the said pipe string within the limits of 0.9-0.98 and said limiter of axial motion of the said hammer is made in a form of a flexible suspension support one end of which is fastened at the mouth of the well and the another end is connected with the said hammer.
Additionally:
A weight is suspended on a flexible suspension support under the hammer;
The hammer is made in a form of a garland of hammers placed under each other on a flexible suspension supports;
The hammer is made in a form of a ball;
The hammer is made in a form of a cylinder;
The hammer is made in a form of a cone;
The hammer is made in a form of a cylinder and a hemisphere connected to it;
The hammer is made in a form of a cone and a hemisphere connected to it;
The hammer is made in a form of a ball and a hemisphere connected to it;
The hammers in the garland are made different by mass;
The hammers in the garland are placed equidistantly;
The hammers in the garland are placed non equidistantly;
The hammers in the garland are of the same shape;
The hammers in the garland are of the different shapes;
The hammer is made hollow and its inner cavity is filled with a liquid having density of 1-13.6 grams/cub.cm;
The hammer is made hollow and its inner cavity is partially filled with a liquid having density of 1-13.6 grams/cub.cm;
The pipe string is fully or partially filled with a liquid having density of 1-13.6 grams/cub.cm;
The pipe string is fully or partially filled with the liquids having different densities;
The pipe string is fully or partially filled with the liquids having different viscosity.
The nature of criteria defining the originality of the proposed method can be proved by the following:
making of a hammer to provide ratio of its maximal cross-section to inner transverse cross-section of the string within the limits of 0.9-0.98 is based on that if this ratio is less than 0.9, the hammer turns to rotating along the pipe axis (it rolls on the pipe wall). It was revealed during laboratory studies and immediately in the wells and can be explained by specifics of pressure distribution in semi moon-like clearance. If the ratio is 0.9-0.98 the clearance becomes more uniform by width thus resulting in that the pressure distribution in the flow passing over the hammer becomes more uniform and the hammer changes over to regime of transverse vibrations (it was also observed at the lab setup);
selection of a flexible suspension support follows from that it practically doesn't restrict freedom of radial motion of the hammer;
speed of axial motion of the hammer is selected from a condition o
Ivannikov Ivan Vladimirovich
Ivannikov Vladimir Ivanovich
BIP Technology Ltd.
Collard & Roe P.C.
Walker Zakiya
LandOfFree
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