SU1004625A1 - Method of working bottom-adjoining zone of injection well - Google Patents

Description

The invention relates to the oil industry and can be used to increase the injectivity of injection wells in oil fields.

The known method of increasing the injectivity of injection wells, based on hydraulic fracturing, consists in artificial formation and expansion of cracks in bottom-hole formation rocks by creating elevated pressures in fluid that is injected into formation 1,

The disadvantage of this method is the difficulty of creating high pressures in the reservoir and multiple treatments.

Closest to the proposed method is a method for treating the wellbore zone of an injection well, which involves injecting a reagent into the wellbore zone, followed by drilling the well into a self-draining C21. Hydrochloric acid is most often used as a reagent.

The main disadvantages of this spot are the complexity and duration of the work due to the need for installation

A large number of special equipment and long periods of reagent delivery, lacked effectiveness, as the reagent. Highly permeable interlayers, mainly due to their use: expensive reagent and equipment corrosion

10 wells.

After well pumping on a self-discharging fluid after acid injection, large quantities of the liquid are to be collected, transported and buried in

15 special places.

The purpose of the invention is to increase the injection capacity of the injection well and simplify the technology of the method.

2Q

The goal is achieved by the fact that, according to the method of treatment, the bottom-hole zone of the injection well, including injection into the bottom-hole zone of the reagent well 25, followed by treatment of the wells with self-priming, the water-hydrate mixture is injected as a reagent.

The water hydrate mixture has low filtration properties in

30 in the injection process, it is filtered on the rocks of the bottomhole zone, clogging up: liquid channels and reducing the permeability of the bottomhole zone. At the initial moment, the hydration phase of the most permeable intervals of the wellbore zone of the injection well is blocked by the hydration phase, as a result the profile of the injectivity is leveled.

When reducing the injectivity of the well by not less than 50%, the injection of the water-hydrate mixture should be stopped and the well should be worked to self-discharge. As a result of a sharp decrease in pressure at the wellhead to the atmospheric hydrate phase in the wellbore, it is decomposed into gas and water, which contributes to intensive well development on the principle of gas lift fc by the difference that the gas appears directly in the water flow. After a well is started at the self-pouring out, the least blocked by the hydrate phase is -., From the interlayer with the lowest permeability, at the initial moment the greatest inflow of fluid into the well occurs, which ensures their intensive cleaning. During the decomposition of hydrates, gas is released under high pressure, which promotes the ejection of dirt, mechanical impurities and rust from the near-abomal zone.

In the most permeable interlayers, decomposition of the hydrate phase begins from the borehole wall deep into the formation. The gas and water released during decomposition of hydrates contributes to intensive and uniform in depth removal of dirt from the bottomhole zone.

Thus, in the proposed method, the hydrivative phase is used as a temporary clogging material to create large ones. depressions in the bottomhole zone during the decomposition of hydrates, filtered to a shallow depth in the formation to obtain, as a result of the decomposition of the hydrate, a fine mixture, the movement of which with high velocities in the bottomhole zone sharply increases the effect of its purification from dirt and mechanical impurities; to ensure uniform bottomhole zone cleaning regardless of the initial permeability of the seams.

The proposed method is implemented as follows.

The injection well is connected to the water conduit, and a gas injection device is installed near the wellhead. The source of gas supply may be gas wells or gas pipelines of the associated petroleum gas collection system.

The water injection pressure, water temperature, and gas flow rate are selected in accordance with the conditions for the formation of hydrates from this gas. The hydrate mixture is pumped into the well until the nofta pickup rate is not less than half. After that, the well is stopped for 2-4 hours, and then it is worked out by self-ebbing until the water flow stops.

The table presents the test results.

Pumping

water

Self-motivated

ten

Pumping

1.4 water

ten

The liquid is light without significant content of dirt

ten

81

Liquid carbonated containing particles of clay and rust

ten

First, the effect of a well on a discharge on its injectivity is determined. For this, water is injected into the well (P 90 atm), with a maximum discharge of 1000. After the stop, the well is worked on self-oil for 10-12 hours. Then water is again supplied to the well, with the limiting flow rate being 1000 m / day. As can be seen from the table, the injectivity of the well does not change.

The second stage of testing is the injection of a water-hydrate mixture into the well. For this, a water from a well at a flow rate of 1000 w / day and a pressure of 90 atm is supplied through the mixer with gas from the well in a ratio that ensures its full transition to the hydrate phase at the bottom of the well (see table). After 6 hours of pumping the mixture, the injectivity of the well is halved. The well is stopped for 3 hours and then worked on a self-outflow. The water coming from the well contains a significant amount of mud and rust particles. Then water is again supplied to the well at a pressure of 90 atm. At the same time, the limiting flow rate of water is 1,400 m / day.

Thus, as can be seen from the test results, acceleration

the injection well is increased by 40%.

Analysis of the results of treatment of wells with hydrochloric acid (in 5 wells) and a water hydrate mixture (in one experimental well) indicates the effectiveness of the water hydrate (40%) as compared to hydrochloric acid (30%). processing.

According to preliminary calculations, the economic effect on one injection well is 20 thousand rubles. in year.

The form of the invention

The method of treating the bottomhole zone of the injection well, including the injection of a reagent into the wellbore zone of the well, followed by drilling the well into a self-flowing, characterized in that, in order to increase the injectivity of the injection well and to simplify the process, a water mixture is hydrated.

Sources of information taken into account when examining

1. Muraviev I.M. and others. Development and exploitation of oil and gas fields. M., Nedra, 1965, p. 208.

2. In the same place 199 (prototype).

Claims (1)

SUMMARY OF THE INVENTION ^ 5 Method for treating a bottom-hole zone of an injection well, comprising injecting a reagent into the bottom-hole zone of a well, followed by self-discharging of the well, characterized in that ,’’ j 25 mixtures.