RU2456431C1 - Water influx isolation method - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: water influx isolation method involves installation of process shield using the solution containing Mikrodur RU, Sulfatsell, ethylene glycol and water at water-cement ratio of 0.8-0.9. Installation of the above shield is performed in terrigenous formation which is by 5-10 m higher than oil-water contact on the basis of 0.5-2.0 m³ per 1 m of effective formation thickness at the following component ratio, wt %: Mikrodur RU 51.7-54.6, Sulfatsell 0.6, ethylene glycol 1.1, and water 43.7-46.6.

EFFECT: improving bottom water insulation, providing the reduction of water content of wells during development of oil and gas deposits.

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Description

The invention relates to the oil and gas industry and is aimed at improving the efficiency of bottom water isolation in the development of oil and gas fields. There is a method of isolating the influx of bottom water into the well, which consists in pumping an aerated cement mortar into the bottomhole zone and then a fluorosilicon fluid product (USSR author's certificate No. 939739 E21B 43/32). The disadvantage of this method of isolating bottom water is the low efficiency of water isolation, the increased complexity of the technology for injecting solutions into the bottom-hole formation zone (PZP).

Closest to the proposed technical solution for isolating bottom water inflow is a method of injecting an organosilicon emulsion into an aquifer, which consists in increasing the thickness of the natural lenticular layer by creating an artificial screen under it with a radius equal to twice the thickness of the cut-off layer of the aquifer, providing an anhydrous mode of operation for the oil-water layer. Anhydrous mode of operation of the well is achieved by creating an artificial screen under a sealed lenticular layer. When determining the thickness of the screen proceed from the condition that a meter of the thickness of the layer withstands a pressure drop of 15 Pa. After injection of the insulating substance and its curing, a screen is obtained that can withstand a pressure drop of 3.0-8.0 MPa. Then, a cement bridge or explosion packer is installed and perforated in the zone of the subsequent fluid selection (RF patent No. 20155312 E21B 43/22).

This method has insufficient reliability of isolating plantar water when creating a technological screen, since when an organosilicon emulsion is injected into an aquifer under a sealed lenticular interlayer, a screen is formed, which is an unstable gel composition, which collapses during development by contacting it with formation water, which leads to disintegration technological screen and penetration of produced water into the perforation interval.

This method has a significant consumption of chemical reagents and is ineffective in the absence of a densified natural lenticular layer in the section of the well to create a technological screen in order to isolate plantar water.

The objective of the invention is to develop an effective way to reduce water cut in oil and gas wells.

The technical result of the invention is to increase the isolation of bottom water, providing a reduction in water cut in wells in the development of oil and gas fields.

The specified technical result is achieved by reducing the water cut of the wells by installing a technological screen from a solution of microdura RU with sulfacell and ethylene glycol with a water-cement ratio (W / C) of 0.8-0.9, which is pumped into the perforation interval 5-10 m above the oil-water contact from the calculation of 0.5-2.0 m ³ per 1 m of the effective thickness of the terrigenous layer in the following ratio of components, wt.%.

microdur RU 54.6-51.7 sulfacell 0.6-0.6 ethylene glycol 1.1-1.1 water 43.7-46.6

This method is based on the creation of a technological screen to reduce the water cut of oil and gas wells during their operation. The creation of the screen is achieved by injection of a solution of microdura RU with sulfacell and ethylene glycol and a chemical reaction between them during the formation of the technological screen in the terrigenous layer.

The main component of the solution is microdur RU - a mineral hydraulic binder with a certain stable chemical and mineralogical composition, is divided into three grades according to the maximum particle size, which should not exceed a weight percentage of d ₉₅

- Xd ₉₅ <6.0 μm;

- Ud ₉₅ <9.5 μm;

- Fd ₉₅ <16.0 μm.

Produced by DyukkerHoff - Sukhoi Log LLC, Sukhoi Log.

Sulfacell is produced in accordance with TU 2231-013-32957739-2001 of Polycell CJSC, Vladimir.

Ethylene glycol is produced in accordance with GOST 10164-75 LLC "Biomedkhim", Ufa.

The method is as follows. According to geophysical research data, the nature of oil and gas saturation is established in the production casing and the oil-water contact is established. 5-10 m above the oil-water contact, the production string is perforated. The tubing is lowered into the well with a PD-YAG packer 2, which is placed 10-15 m below the perforation interval of the production formation. After that, the calculated amount of a solution of microdura RU with sulfacell and ethylene glycol with a water-cement ratio (CC) of 0.8-0.9 at the rate of 0.5-2.0 m ³ per 1 m of the effective thickness of the terrigenous reservoir is pumped through the tubing with a cementing unit. The injection is carried out with constant monitoring of the injection pressure and injectivity at a maximum injection pressure not exceeding 0.8 formation pressure. Then the tubing string and the PD-YAG packer 2 are raised to a height of 50-100 m and the well is washed. In the injection zone of the solution of microdura RU with sulfacell and ethylene glycol, a cement bridge is installed and pressure tested.

For experiments on checking the quality of water supply isolation by this method, samples of quartz sand were taken, which were previously dried in an oven to a constant weight and pressed in a cylindrical container at a pressure of 25.0 MPa, which corresponds to the effective rock pressure for the Lower Cretaceous deposits of deposits in Western Siberia. The sample was saturated with formation water with a salinity of 18 g / l and placed in a core holder of a simulator of reservoir conditions, where formation water was filtered through the sample and the permeability of the formation water was determined.

After determining the permeability, a solution of microdura RU with sulfacell and ethylene glycol was pumped into the sample until the filtration was completely attenuated. The experiment was stopped to hold the sample for reaction from 19 to 20 hours, which was established experimentally with sample samples in surface conditions. After the solution was solidified, pressure was applied to the sample and the screen resistance to penetration of formation water and pressure drop were determined, at which the process screen retains its stability. According to the data of the experiments, the resistance of the screen to the penetration of formation water is from 11.0 MPa to 11.5 MPa (table).

Claims (1)

The method of isolating water inflow, which consists in installing a technological screen, characterized in that from the solution of microdura RU with sulfacell and ethylene glycol with a water-cement ratio of 0.8-0.9, a technological screen is installed in a terrigenous layer 5-10 m above the oil-water contact based on 0.5-2.0 m ³ per 1 m of effective formation thickness in the following ratio of components, wt.%:
microdur RU 54.6-51.7 sulfacell 0.6-0.6 ethylene glycol 1.1-1.1 water 43.7-46.6