RU2250990C1 - Method for hydro-isolation of watered productive bed - Google Patents

Abstract

FIELD: oil industry.

SUBSTANCE: in the method for hydro-isolation of watered productive bed, including serial forcing into bed via tubing pipes string of isolation polymer substance - polymer solution with dispersion phase and then suspension of rubber powder, as dispersion phase water-resistant, but oil-soluble material is used, for example, special brand thermoelastoplast, and said dispersion phase until 20% is injected into rubber powder suspension.

EFFECT: higher efficiency, higher oil yield.

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Description

The invention relates to the field of the oil industry, and in particular to methods of waterproofing a watered reservoir, mainly in fractured formations.

A known method of waterproofing a waterlogged reservoir [AMELIN B.A. and others. New methods of non-metallic fastening of boreholes, M., Nedra, 1964, pp. 73-74] by injecting a polymer-clay solution into the formation.

Also known is a “Method of isolating water in fractured formations” [RU No. 2112875 C1, 1998], which includes sequential injection of dispersed phase polymer material and a suspension of crumb rubber with a particle size of 0.1-3 5 mm.

This method according to the technical nature and the achieved result is closer to the proposed one and can be adopted as a prototype.

A common disadvantage of these methods is that the dispersed phase in the form of clay particles contained in the insulating materials injected into the formation, entering the oil-saturated parts of the formation, reduces the reservoir properties of the formation, which leads to a decrease in production capabilities of the formation. At the same time, restoration of reservoir properties of a formation with clay particles that got there as a result of waterproofing works is laborious due to the impossibility of their extraction or destruction in reservoir conditions.

In addition, their use does not exclude the removal of sand from the formation into the well, especially “thin” sands. As you know, the removal of sand from the reservoir occurs most often from interlayers filled with “thin” sand. Rubber crumb does not pass into the pores of such interlayers, and if it penetrates, it is only partially, and when the well is developed, they are carried into the well, while the sand continues to flow.

 The aim of the present invention is to improve the waterproofing properties of the insulating material, reduce its negative impact on the reservoir properties of the formation and, therefore, increase the production capacity of the well.

This goal is achieved due to the fact that in the method of waterproofing an irrigated productive formation, which includes sequential injection of a tubing of insulating polymer material — a polymer solution with a dispersed phase and then rubber crumb suspension — into the reservoir of tubing, the water-insoluble but soluble is used as the dispersed phase in oil, a material, for example, DST-30 or DST-RM thermoplastic elastomer, and said dispersed phase up to 20% are introduced into a rubber crumb suspension.

Previously conducted patent studies with a retrospective of 20 years have shown that technical solutions for a similar purpose and with such a positive effect have not been found, which allows us to conclude that the proposal meets the criterion of “novelty” and inventive step, and its industrial applicability is shown in its full description.

The method is carried out in the following sequence.

First determine the path of water inflow and injectivity of the reservoir, as well as the expected pressure on the production string. Next, a tubing string with a packer is lowered into the well in the interval of the reservoir in its roofing part, disconnected from the rest of the well.

The first portion of the insulating material in the form of a polymer solution is prepared under field conditions using traditional technology with the addition of a dispersed phase, which is oil-soluble but water-insoluble material, such as thermosilicon grade DST-30R or DST-RM, which is produced by the Voronezh plant “Thermoelastoplast” Voronezhsintezkauchuk OJSC in the form of a powder according to TU 38.40327 - 98, Liter 0., date of introduction 05.09.98, DST-ZOR or DST-RM - are block copolymerization products of styrene and butadione in races hydrocarbon in the presence of an organolithium initiator, thermoplastic elastomers are soluble in light oils, benzene, toluene.

The polymer insulating solution is prepared in fresh or waste water. In this case, a water-soluble partially hydrolyzed high molecular weight polyacrylamide with a concentration of 0.01 - 0.05 wt.% Or water-soluble cellulose ethers with a concentration of 0.01 - 0.1 wt.%, Or salt-resistant polymers such as DK - Drill, are used as a polymer in solution. Proestol - 2540 with a concentration of 0.05 - 0.15 wt.%. Such polymer concentrations provide suspension stability.

The injection of the solution is carried out using pumping units, for example, type CA - 320 M in an amount of 3-10 m ³ per meter of thickness of the formation, depending on its injectivity and fracture, but not less than 10 m ³ , while monitoring the injection pressure with a pressure gauge installed on the mouth on the discharge line, and the volumetric flow rate of the solution.

A polymer solution based on thermoplastic elastomer, getting into the flooded reservoir, primarily in its cracks and channels of water inflow, pushing it deeper into the reservoir, creates a waterproof screen, and thermoplastic elastomer, which partially fell into the pores of the oil-saturated part of the reservoir, softens in contact with oil, and then during development or operation of a well, it is removed from the formation along with oil. After the calculated volume of polymer solution is injected into the formation, without interrupting the injection process, a suspension of rubber crumb (RC) is pumped in about 10-15 m ³ , the particle size of the RC is 0.1 -3.5 mm, at a concentration within 8-30 wt.%. The concentration and size of a portion of the RC in the suspension is selected depending on the opening of the cracks and the injectivity of the formation. The same thermoplastic elastomer powder, such as DST-30R or DST-PM, is used as the dispersed phase of the suspension of RK, and polymer solutions are used as the carrier of particles in the suspension.

The introduction of thermoplastic elastomer powder into the RK suspension is based on the data obtained during pilot operations at 1 m of the thickness of the perforated formation interval, which is reflected in the table below.

Collector type Rubber consumption
crumbs, kg Consumption of thermoplastic elastomer,
kg /% Pickup
wells at
m ^Z / h, P = 5 MPa Terrigenous 10 1-2 / 10-20 10-20 fissured twenty 2-4 / 10-20 20-30 Carbonate thirty 4-6 / 13.3-20 twenty fissured fifty 10/20 more than 20

In the process of pumping the suspension of the RK, the pressure at the mouth and the flow rate of the suspension of the RK are controlled. After pumping the calculated volume of the suspension of the RK, it is forced through with water, the packer is put into transport position, and the well is left alone to restore equilibrium in the near-stem part of the well. Then the well is washed and mastered using one of the known methods. When pumping a suspension of RK into the reservoir, the following occurs. Suspension of the RC during the injection process pushes the previous portion of the polymer solution deep into the reservoir, in which cracks and channels, first of all, are filled with the dispersed phase in the form of thermoplastic elastomer and rubber crumbs, while the thermoplastic elastomer, in contact with oil, swells, is like

cementing rock with crumb rubber, thereby reliably blocking the exit paths of not only the polymer solution pumped as the first portion, but also the “thin” sand from the interlayers.

The technical and economic advantage of the proposal is to increase the duration of the anhydrous period of oil production (or with a low content) by creating a better screen that prevents the exit of a pre-pumped polymer solution with thermoplastic elastomer, which is achieved due to the presence of the latter in both portions of the injected solutions. The widespread use of the method in the oil fields will give tangible economic benefits in terms of reducing labor costs and time, as well as material resources.

Claims (1)

A method of waterproofing a flooded reservoir, comprising sequentially pumping tubing into a reservoir of an insulating polymer material — a polymer solution with a dispersed phase and then a suspension of rubber crumb, characterized in that a water-insoluble but oil-soluble material is used as the dispersed phase, for example , thermoelastoplast brand DST-30 or DST-PM, and the specified dispersed phase up to 20% is introduced into a suspension of rubber crumb.