RU2206715C2 - Liner for water-encroached producing well - Google Patents

Abstract

FIELD: oil producing industry, particularly, means for protection of formation reservoir properties. SUBSTANCE: liner has packer and plugged from bottom pipe string with check valve. Packer is made of two oppositely directed self-sealing packings. Check valve is made in form of hole in liner lower part and additional self- sealing packing installed with its funnel downward. In upper part of liner, but below packings, hole may be made which is closed with slide valve having float with positive buoyancy in oil. EFFECT: simplified design of liner and technology of its operation. 2 cl, 3 dwg

Description

 The invention relates to the oil industry, in particular to means for preserving the reservoir properties of the reservoir.

 Known liner containing a packer and a pipe string, which is abutted in the bottom and perforated in the lower part (see Ibragimov GZ and other Development of oil fields, T. II.M., 1994, p.76).

 The disadvantage of the liner is the lack of protection of the reservoir from the kill fluid during repairs.

 Closest in its technical essence to the proposed deep-well pumping unit for oil production by AS 724693. It contains a liner, which is a pipe string with a packer at the top and a check valve at the bottom.

 The valve prevents killing fluid from entering wells during well repair.

 The disadvantages of the device is the design complexity of the packer and valve.

 The aim of the invention is to simplify the design of the shank and simplify the work with him.

 This goal is achieved by the fact that in the well-known liner for a water-cut producing well, including a packer and a pipe string with a check valve, the packer is made in the form of two oppositely directed self-sealing cuffs, and the check valve can be made in the form of an additional self-sealing cuff installed with the socket down, with a hole is made in the bottom of the shank. In addition, for wells with a high gas content in the upper part of the liner, a hole is made below the cuffs, which is blocked by a slide valve with a float having positive buoyancy in oil.

 The essence of the invention lies in the fact that instead of hanging the liner on a stationary packer, it is installed on the bottom of the well, and its upper part is sealed with two oppositely directed self-sealing cuffs. The non-return valve can be replaced by an additional self-sealing cuff, which, like the non-return valve, passes fluid "from the reservoir" and does not pass "to the reservoir". If there is a large gas factor, gas accumulation under the packer is possible, therefore, a spool valve with a float is installed in this case, which discharges gas into the shank.

 Figure 1 shows the shank according to claim 1 of the claims. The shank comprises a pipe string 1 plugged from below with a pair of self-sealing cuffs 2, a check valve 3 and a funnel 10 at the upper end to prevent foreign objects from entering the annulus. Cuffs 2 are located above the reservoir 4, and above the liner is the pumping unit 5.

 In Fig.2, instead of valve 3, an additional cuff 6 is installed, and a hole 7 is made in the pipe string.

 In FIG. In the upper part of the liner, a hole 8 is made with a slide valve 9 having positive buoyancy in oil.

 The shank works as follows.

 At the next repair, the liner is lowered into the flooded production well so that the cuffs 2 are above the reservoir, and the check valve 3 is below the reservoir. When pump 5 is operating, fluid from the formation through valve 3 first enters the liner cavity, and then further into the well cavity and the pump.

 Since the density of oil is less than that of water, oil accumulates under the cuffs, and it fills the entire space from the cuff installed with the socket down to the check valve 3. And below the valve there is water from the reservoir. As a result, there is always oil, and not water, against the formation, as in normal well operation.

 During repairs, the check valve 3 and the upper cuff do not pass the kill fluid to the formation and prevent the permeability of its bottom-hole zone from deteriorating from squeezing the kill fluid into it. And the funnel 10 prevents objects from accidentally falling into the well during the repairs in the gap between the liner and the casing, which can lead to jamming of the latter.

 When used as a check valve cuff 6 (figure 2), the shank works the same way.

 With a large gas factor and bottomhole pressure below the saturation pressure, the third option is used.

 In this case, not only oil but also gas accumulates under the cuffs 2, and when its level decreases below the float valve 9, the latter falls and the gas goes through the hole 9 into the well cavity. If the gas is not released, then during repairs it can be crushed into the reservoir, which will worsen its permeability.

 Thus, the proposed liner both during operation and well repair prevents water and killing fluid from entering the formation, which preserves the permeability of its bottom-hole zone.

 In addition, the constant contact of the exposed surface of the formation with oil leads to gradual penetration of oil into the flooded areas of the formation and their hydrophobization during pressure fluctuations, due to which a decrease in water cut of the product can occur.

 If necessary, using a tube, the liner can be easily removed from the well.

Claims (2)

 1. The shank for a watered production well, comprising a packer in the form of cuffs located above the reservoir and a pipe string plugged at the bottom with a check valve, characterized in that the pipe string has a funnel at the upper end, the packer is made in the form of two oppositely directed self-sealing cuffs and the check valve is made in the form of an opening in the lower part of the shank and an additional self-sealing cuff installed with the socket down.  2. The shank according to claim 1, characterized in that in the upper part of the shank, but not lower than the packer cuffs, a hole is made that is blocked by a slide valve with a float having positive buoyancy in oil.

Images