SU1314012A1 - Method of consolidating hole-bottom zone of formation - Google Patents

Abstract

The invention relates to the oil production industry and makes it possible to increase the efficiency of the attachment of the downhole zone of the reservoir of oil wells. To do this, a cement mortar (CR) is pumped into the well and forced into the reservoir by means of a plastic fluid. The perforation of the productive interval, which is carried out before the CR solidifies, is then carried out. In order to speed up the setting time (curing) of the CR, calcium chloride is introduced into it in an amount of 1-6 wt.%. The presence of a visco-plastic fluid as a buffer element prevents the CR from diluting with a squeezing fluid and ensures that the perforation channels in the hardening CR are fixed. The presence of calcium chloride in the CR leads to a forced transfer of the CR to a solid state. 1 hp f-ly, 2 tab. (L

Description

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The invention relates to the oil industry, in particular, to the mounting of the bottomhole formation zone of oil wells exposed to sand and water.

The purpose of the invention is to increase the attachment efficiency.

The method of securing the near-wellbore zone of the reservoir involves injecting cement mortar into the well, pushing it into the reservoir by means of a plastic fluid and perforation of the productive interval, which is carried out before the cement (grouting) mortar is cured,

In order to accelerate the setting time (hardening) of the cement (cement) solution, calcium chloride is introduced into it in an amount of 1-6 wt.%.

The presence as a buffer element in a plastic fluid prevents dilution of the cement slurry with a squeezing fluid (technical water) and ensures the fixation of the perforation channels in the hardening cement slurry. The pressure from the initiated blast wave during the perforation of an uncured cement slurry contributes to its better penetration into cracks and cavities, an increase in the contact adhesion of the cement material to the formation rock, and a directional significant pressure drop formed during the combustion of the powder charge of the perforations causes compaction of the pressure relief bulbs. and the separation of excess water, which ensures the formation of cement (cement) stone with high strength and optimal filter indicators.

The explosive nature of the increase in pressure significantly reduces the time of setting (curing) of the cement slurry, and if calcium chloride is present in an amount of 1-6 wt.%, It leads to a forced transition - a solution to a solid state.

The proposed method of securing the bottomhole formation zone is performed by standard equipment and consists of the following.

Cement slurry is prepared in a mixing machine and pumped into the well to be processed by a casting machine. Following the cement slurry, the buffer is supplied to the well in a highly plastic fluid, and then

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technical water. After pressing the cement slurry in the ecoplastic fluid into the reservoir, the perforator is lowered into the well and the perforation interval is perforated in the wellbore zone in the wellbore zone.

To ensure forced setting (curing) of the solution, when performing perforation, calcium chloride in an amount of 1-6 wt.% Is introduced into the solution before injection.

After completing the perforation and lifting into the perforator from the well, it is put into operation using the soft start method.

The mass of the injected cement slurry, buffer fluid and process water, as well as the parameters of the perforator are determined by standard calculation, depending on the state of the column and the bottom of the well, the thickness of the reservoir to be fixed and its absorptive capacity.

The content in the solution of calcium chloride (CaClji) is regulated depending on the depth of the object and the temperature of the medium.

The effect of temperature at the boundary values of the CaCl2 content on the setting time of the cement slurry with a density of 1930 kg / m is given in Table 1.

From tab. 1, it follows that the starting time for the cement mortar to begin to set, with boundary values of calcium chloride in the bottomhole temperature range of 293-323 K, varies from 55 to 305 minutes. Considering

these intervals of setting of the solution and the ratio of its total time spent on all operations associated with the final work on the mounting (leaching of excess cement mortar, raising the filling pipe from the well, carrying out perforation and final operations), and the necessary concentration of CaCl is selected .

A nomogram has been developed to determine the CaCl content in the solution for particular well-1k conditions.

The main purpose of the MAS in the proposed method is to ensure the fixation of the perforations in the forced hardening cement slurry.

At the time of perforation, the VAS (which is not in the perforation channels, which are not yet present) is pushed aside by the pressure of the gases from both the cement slurry and into it. At the time of the explosion of powder charges, the VUS (not losing its plastic-elastic properties) is separated into the boundary with the solution and into the channels.

When channels appear, the VUS manages to occupy the cavity of the channels before they begin to deform under the weight of the upstream rocks and cement, which is facilitated by the fact that the cement is forced into a solid state, and the hydrostatic column of the well fluid prevents the flow of the VUS.

The accelerator setting time (CaCl) in the proposed method is used to adjust the setting time and allows you to accurately determine the time at which the perforation is to be performed.

PRI me R. For the purpose of comparative analysis, a test of the proposed method for fastening the bottomhole zone of the plastar was carried out in wells characterized by frequent repairs and losses of oil production due to abundant sands that had previously been anchored by known technology.

The well is equipped with a production column (168 mm) with artificial bottomhole of 1272 m. The existing filter in the range of 1244-1250 m and exploits the productive horizon. The well was put into operation after the return of July 01, 1984. With a flow rate of 0.7 tons of oil and 5.0 tons of total fluid and the presence of mechanical impurities in the amount of 1.4%. The interrepair period (well operation) was 10–15 days. In order to combat sanding in the well, the bottom was filled with cement mortar according to standard technology with an overpressure at the mouth of 10 MPa with vymatshanie cement to the bottom (1272 m). Used 5.0 tons of portland cement.

After treatment, the well came into operation with a flow rate of 0.7 tons of oil and 5.0 tons of total fluid with the same indicators of repair and the overhaul period of work. Thus, the mounting using standard technology was not effective.

01.22.85. Work was done to secure the well bottom zone

The proposed fastening method with perforation in uncured cement mortar.

In the CM-20 cement mixing machine, 3.0 tons of cement mortar were prepared with the addition of calcium chloride (3% by weight of the solution) and the TSA-320 cementing unit pumped it (at an overpressure at the mouth of 10 MPa) through pump-compressor pipes and openings the existing well filter into the bottomhole zone with leaching of residual solution to a depth of 1272 m. Then a 2.0 m buffer in a coplastic fluid — oil (characteristics shown in Table 2) is pumped into the well; after 5 h, the existing filter is clouded PC-80 perforator.

After mastering. The well was commissioned using the mechanized method (NSV-1) using the method of smoothly increasing the depression to a formation with a flow rate of up to 2.7 tons of oil and 3.9 tons of total fluid.

After the implementation of the process, the well is more than 2 months. works without repairs, and the volumetric content of mechanical impurities in the produced fluid decreased to 0.04%.

Thus, the proposed method allows increasing the current and total oil withdrawals by improving the reservoir opening, significantly limiting sand and water supply by creating a reliable cement screen and enhancing the contact of the cement stone with the production column and productive rock, and also significantly reducing the strain of the rock. by reducing the hydraulic resistance in the bottomhole formation zone.

Claims (2)

1. A method of securing the near-wellbore formation zone, which includes pumping cement mortar into the well, forcing it into the reservoir and producing a perforation of the productive interval, characterized in that, in order to increase the attachment efficiency, the cement mortal is forced into the reservoir, and productive interval perforation produced prior to curing the cement slurry. 2. The method according to p. 1, about tl and h and u and with the fact that, in order to accelerate 293 323 305 120 293,874 220.0 313 860 180.9 Editor E. Kopcha Compiled by I. Lopakova Tehred L.Oleynik Proofreader N. King Order 2189/33 Circulation 533 Subscription VNIIPI USSR State Committee for inventions and discoveries P3035, Moscow, Zh-35, Raushsk nab. D. 4/5 Production and printing company, Uzhgoro; d, st. Project, 4 - 13140126 The scientific research institute of terms for scaling cement mortar, Kala chloride is introduced into it; 1and in the amount of 1-6 May.%, Table 1 155 55 210 85 table 2