RU1802084C - Method for blocking lost-circulation formation - Google Patents

Abstract

Usage: oil and gas industry. The inventive pumped as 1 reagent bentonite chalk solution of the composition, wt.%: Bentonite clay powder 20.0-25.0: ground chalk 7.0-8.0; sulfanol 0.10-0.15; carboxymethyl cellulo. ea 1.0-1.5; the rest is water, which is prepared by mechanical stirring, and inhibited reagent hydrochloric acid in the amount of 10-20% of the volume of the first reagent as 2 reagent. As inhibited hydrochloric acid, a solution containing (wt.%) Hydrochloric acid 23-24, KI-1 inhibitor 1.0-1.5, and the rest is used. The KI-1 inhibitor is a mixture of 25% catapine B-300-alkylpolybenzylpyridinium chloride, 25% urotropine, and the rest. After the delivery of two reagents to the absorbing layer, they are mixed and the well is left to sediment for 4-6 hours. 1 table .. 1 s. P. f-ly. ate with

Description

The invention relates to the oil and gas industry, in particular, to methods and compositions for blocking absorbing formations before installing dividing cement bridges during well overhaul.

The aim of the invention is to improve the quality of blocking the absorbing formations by creating a highly viscous non-filtering composition in the well from easily pumpable initial compositions. This goal is achieved by the fact that in the known method, including the separate injection into the well of reagents with their subsequent mixing into the interval of occurrence of the absorbing layers, two types of compositions are pumped in turn, having low rheological characteristics and good pumped g,

bentonite-chalky. and then a hydrochloric acid inhibited by a KI-1 inhibitor. moreover, the second volume is 10-20% of the first, and the formation of an unfiltered, highly viscous carbonated swab occurs during the mixing and chemical reaction of these formulations, increasing the quality of the blocking of the absorption interval.

Stock solutions from which a highly viscous, non-filtering composition is formed include the following components. The first composition, wt.%. bentonite clay powder 20-25 ground chalk 78 sulfanol. 0.1 0.15 KM C 1.0-1.5 water the rest

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The second composition, wt.%: Hydrochloric acid 12% concentration 23-24 KI-1 inhibitor 1.0-1.5 water the rest The second composition takes 10-20% of the volume of the first.

If it is necessary to destroy highly viscous carbonated gel in the uncemented part of the interval of the reservoir, an additional amount of hydrochloric acid solution is pumped into the bottomhole zone in a volume equal to the destruction volume of the gel, as in the well-known technology of hydrochloric acid treatment of the reservoirs.

A comparable analysis of the proposed technical solution with the prototype shows that the inventive method differs from the prototype by the separate injection of two reagents, when the gel is formed as a result of chemical interaction.

Thus, the proposed method meets the criterion of novelty. The proposed method for blocking the bottom-hole zone is easy to implement and has high reliability. The implementation of the method is as follows.

A calculated volume of a bentonite-chalk solution with a density of 1230-1270 kg / m is prepared and pumped into the well, then a hydrochloric acid solution of 12% concentration inhibited by the KI-1 inhibitor in the ratio of May 1-1.5,% is pumped. The KI-1 inhibitor is a mixture of 25% catapine B-300-alkylpolybenzylpyridinium chloride

Spnap + 1 SBH4CH2 (SBH4CH2), where 25% of urotropine;

the rest is water, (B. G. Loginov and other Guidelines for acid treatment of wells, Nedra, M., 1966, p. 44, 73-74). The volume of the injected hydrochloric acid solution with the addition of a KI-1 inhibitor is 10-20% of the volume of the bentonite-chalk solution. During the sale of these solutions to the interval of the absorbing formations, they are mixed and reacted with the release of carbon dioxide, the formation of calcium chloride.

As a result of the reaction, a highly viscous carbonated gel is obtained. After delivery of the initial components to the design interval, the pump-compressor pipes are raised above the absorbing layer. The excess volume of the blocking composition is washed off and the well is left to sediment for 4-6 hours. During this time, the reaction between the chalk and hydrochloric acid has completely passed and the mixture of both compositions turns

a viscous, non-filtering carbonated gel that is difficult to push into the formation. A cement separation agent is installed over the resulting in an elastic-elastic swab.

bridge. After hardening of the bridge, overhaul of the well is carried out. The use of the proposed method and compositions for blocking the absorbing formations eliminates contamination of the formations in the process

overhaul of wells. If it is necessary to destroy the highly viscous gel, an additional amount of hydrochloric acid solution is pumped into the bottomhole zone in the volume of the gel to be destroyed. AT

the reaction produces carbon dioxide, water and water-soluble calcium chloride. Wells are easily mastered without loss of production.

The following are specific examples.

an implementation of a method for producing a gel at the boundary contents of the components.

The presence of an excess of chalk in a bentonite-chalk solution allows the gel to be destroyed by hydrochloric acid

processing. When the gel solutions are kept in laboratory conditions in a thermostated water bath at a temperature of 80 ° C for 3 hours, the structure

solutions did not change.

Implementation of a method for blocking absorbing formations under field conditions.

A bentonite-chalk solution is prepared in a clay mixer or in a milling-jet mill by mixing with water. After preparing the estimated volume of the bentonite-chalk solution (0.2-0.3 m3 per 1 m of the opened interval)

a sublevel is added a surfactant solution. A hydrochloric acid solution is prepared in the tank of the Azinmash-30 aggregate.

The proposed method is illustrated in the diagrams of Figs. 1 and 2, where: 1 - tubing; 2 - gate valve fountain; 3 - valve on the pipe head of the fountain valves; 4 - killing fluid; 5 - bentonite-chalk solution; 6 - separation fluid; 7 hydrochloric acid solution to form a gel; 8 is a squeeze solution (killing fluid); 9 - carbonated gel; 10 - destroyed gel; 11 - filtered part of the well; 12 - cement bridge;

13 is a hydrochloric acid solution for disrupting the gel.

Estimated volume is pumped into the well plugged through the fluid through the valve 2 and tubing 1, with the valve 3 closed, with the pump unit

a bentonite-chalk solution 5, then a separation volume of water 6, 100-150 l and a calculated volume of 12% hydrochloric acid 7. The solutions are discharged into the bottom-hole zone of the formation with a squeezing volume of water 8. When the bentonite-chalk solution of the filter part of well 11 reaches solutions in the formation, where they were mixed, forming a gel. The subsequent sharp increase in pressure during the delivery of solutions will indicate blocking of the bottom-hole zone of the Pasta with the formation of aerated, highly viscous gel 9,

With a sharp increase in the purge pressure of the solutions, the valve 3 must be open. The installation of the cement bridge 12 in the well should be carried out after washing the wellbore.

In order to obtain an inflow of gas or oil from the uncemented part of the formation, it is necessary to destroy the gel by injection of hydrochloric acid 13. Having obtained the destroyed gel 10, a well is developed.

The advantages of the proposed method of blocking the absorbing layers in comparison with the known following:

improving the quality of blocking the pit-hole zones of the absorbing formations;

reduction in the cost of repairs due to the reduction in cost of the initial components used in blocking;

reducing the complexity of blocking;

raising the culture of production; reduction of repair time and well development.

Claims (2)

1. A method of blocking absorbing formations, comprising separately injecting two reagents into the formation with their subsequent mixing, with the exception that in order to improve the quality of blocking, a solution containing, by weight, is used as the first reagent .%: Bentonite clay powder 20-25; ground chalk 7-8; sulfanol 0.10-0.15; carboxymethyl cellulose 1.0-1.5; water-water, and as a second, inhibited hydrochloric acid, the second reagent being pumped in an amount of 10-20% of the volume of the first reagent. 2. The method according to claim 1, characterized in that a solution containing, in mass%:% hydrochloric acid 23-24; KI-11.0-1.5 inhibitor; water. the rest. Structure Ratio of components wt.% Bentonite Clay Powder - 10 Ground chalk - 5 Surfactant (sulfanol) - 0.05 KMTs-0.5 Water - the rest HCI Ingibir. - 10 from the volume of the reaction. I (catapine 1.0) Bentonite Clay Powder-20 Ground chalk - 7 SAW-0.1 CMC - 1.0 Water - the rest HCI Ingibir. (from V pear. I) .19- - (gfvGdpin 1) Parameters, density - kg / m3, conditional viscosity Those. SNS-Pa Water loss (V) cm3 / 30 min Peel thickness p, mm Malov Zkiy carbonated gel T - not flowing NSYO 50.6-44.2 At 39.5 n 22 Highly viscous carbonated gel Low surfactant and CMC content Structure Ratio of component wt.% Bentonite Resin 21 Ground chalk - 7 SAW -0.15 CMC - 1.5 Zoda - the rest HCI Ingibir. (from V10 (catapine 1.0) Bentonite Resin 21 Ground chalk - 8 Surfactant-0,1 KMTs-1,5 Water - the rest HCI Ingibir. (from V 15 (catapine 1.0) Bentonite glsh about to - 25 Ground chalk - 8 SAW -0.1 CMC - 1.0 Water - the rest HCI Ingibir. (from V 20 (catapine 1.0) Bentonite Bowl - 25 Ground chalk 8 SAW - 0.15 CMC - 1.5 Water - the rest HCI Ingibir. (from V 20 (catapine 1.0) Table continuation Parameters, density kg / m3, conditional viscosity Those. SNS-Pa Water loss (V) cm3 / 30 min The thickness of the crust plmm  p-1240 T - not SNSyo-62.2-56.6 At 38 n 24 T - not flowing NSy- 73.8-69.3 At 36 n 26.5 High viscosity carbonated gel with a low content of surfactants and CMC T - not flowing NSYO-91.4-88.1 At 34 n 29 High viscosity carbonated gel with a low content of surfactants and CMC Vysokov carbonated gel