RU1838584C - Method for isolation of formations featuring water-inflow - Google Patents

Abstract

Usage: oil and gas industry. SUMMARY OF THE INVENTION: An aqueous solution of lolacrylamide with a concentration of 0.1-0.2 may be pumped into the well. %, in an amount of 1.0-2.0 m3 for each 1 l / s of produced water entering the well. Separation fluid is pumped - fresh water. Then, aqueous solutions of calcium chloride and ammonium sulfate are sequentially pumped with a separation liquid — fresh water between them. At the end of the punching, the well is left alone for the time of plugging of the cracks and pores of the formation.

Description

The invention relates to the oil and gas industry and can. be used in the production of drilling operations.

The technical result of the invention is increased efficiency due to pseudo-equalization of the permeability of the formations both in terms of their power and their ability to provide sufficient isolation of small cross-sections, practically eliminating the flow of formation water into the well.

The technical essence of the invention is based on the fact that in the known method isol. water-containing formations, including the injection of aqueous solutions of calcium chloride and aluminum sulfate, according to the invention, before the injection of aqueous solutions of calcium chloride and aluminum sulfate, an aqueous solution of polyacrylamide is injected, solutions of calcium chloride and aluminum sulfate are pumped separately, and after each solution is pumped fresh water, while polyacrylamide is used with a concentration

May 0.1 ... 0.2. % and in an amount of 1.0 ... 2.0 m3 for every 1 l / s of produced water entering the well. 1

PRI me R. During the drilling of the well, at a depth of 520 m, water penetration is revealed in the deposits of the Upper Carboniferous, the intensity of which is 79.2 m3 / h, the density of the pouring water is 1120 kG / m / pressure at the wellhead is 1 MPa.

To conduct insulating work, drill pipes are lowered to a depth of 465 m into the well, and the wellhead is sealed with the wellhead packer.

Hydraulic injectivity tests of wells are being performed. For this, using the cementing unit CA-320 M, water is pumped in three pump operating modes, with pressure control on the pressure gauge. The following results were obtained:

CA productivity - 4.9 l / s. pressure - 1.5 MPa.

-8.7l / s, -2.5 MPa.

-15.3 l / s. -3.0 MPa.

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At the end of the study, plugging mixture is pumped through the drill pipe into the well in the following order:

1) 20 m aqueous solution of polyacrylamide O.15% concentration;

2) dividing portion of fresh water

-0.5 m3;

3) 2 m3 of an aqueous solution of calcium chloride of 30% concentration;

4) dividing portion of fresh water

-0.2 m3;

5) 1.5 m3 of an aqueous solution of aluminum sulfate of 50% concentration.

The plugging mixture is pressed with fresh water in a volume of 4 m. At the end of the push-through, a technological pause

-- 20 minutes. Then, on the measured capacity of the cementing unit, a crane is opened, 0.7 m of displacement fluid is taken and again

pump it into the well. The selection and injection process is repeated four times. Pressure on the manometer (YES at the end of the operation is 7 MPa with a productivity of 4.9 l / s. Then the well is left alone for 3 hours.

At the end of the work, the well is washed and the amount of produced water spout is measured. The residual water intensity is 1.2 m / h.

Such an implementation of the method has a number of positive properties;

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it seems possible to increase the efficiency of waterproofing operations by closing not only large fractures and pores in the formation, but also small and long ones through which a significant amount of produced water enters the well;

2) it is possible to obtain a dense and compositionally stable swab that reliably prevents formation water from entering the well;

3) the cost of treatment is reduced by eliminating the need for repeated or repeated hydroisolation of the aquifer.

Claims (1)

Formula for Acquisition A method of isolating water-producing formations, comprising injecting aqueous solutions of calcium chloride and aluminum sulphate, characterized in that prior to injection of aqueous solutions of calcium chloride and aluminum sulfate, an aqueous solution of polyecrylamide is injected, solutions of calcium chloride and aluminum sulfate are injected separately, after the injection of each solution, fresh water is pumped, while lioecrylamide is used with a concentration of 0.1-0.2 May. % and in the amount of 1.0-2.0 m - for each l / s of produced water entering the well.