RU115404U1 - DEVICE FOR PREVENTING CORROSION OF WELL EQUIPMENT - Google Patents

Abstract

A device for preventing corrosion of downhole equipment, containing a protective case, an electrode, perforated insulators and couplings, characterized in that the electrode is made of composite, the upper part of which is made of steel, the lower part of the electrode is screwed into a magnesium rod placed in a sealed lower case, centered by a dielectric retainer and filled with electrolyte, the tightness of the composite electrode is provided by the upper and lower sealing glands, the bottom of the cover is equipped with a drain plug.

Description

The utility model relates to devices for equipping borehole pumps designed for pumping liquids of high water cut, mineralization, viscosity from oil wells under conditions that cause intense corrosion of oilfield equipment, as well as in the presence of salt and paraffin deposits of oilfield equipment.

A well-known sucker-rod pump for pumping highly viscous fluids from wells (Oilfield equipment; Handbook / Ed. By E.I. Bukhalenko. - 2nd ed., Revised and additional - M .; Nedra, 1990. - 559 p .; silt . (one).

When the plunger moves down in the area of the cylinders enclosed between the plungers, a vacuum is created, due to which the lower valve of the valve unit opens and the formation fluid enters the said zone. The closed upper valve of the valve block unit perceives the pressure of the liquid column and creates an additional downward load, which helps to overcome the hydraulic resistance in the pump and the friction forces of the rod string against the pumped out highly viscous liquid. The latter is very significant, since it eliminates the hang of the rods due to excessive friction.

A disadvantage of the known device is the inability to use a device for pumping fluids from wells with high water cut and mineralization, the presence of a significant amount of abrasive substances, both at the bottom of the wells and washed out of the reservoir, factors contributing to fatigue-corrosion wear of oilfield equipment, including pump and compressor pipes (tubing), sucker rods and borehole pump, due to the occurrence of electrochemical processes that cause its corrosion.

The closest in technical essence and purpose to the proposed invention is a sucker rod pump for pumping highly mineralized liquid and in the presence of significant mechanical impurities (Patent No. 2303164, C1. Published July 20, 2007, BI No. 20) [2].

A drawback of the device’s design is its high hydraulic resistance, significant abrasive wear of the magnesium tread by mechanical impurities (sand) in the fluid to be lifted, and the possibility of tread wear products entering the pump’s flowing part if chemically active reagents (acids, inhibitors, solvents) contribute to the chemical dissolution of the tread.

The purpose of the utility model is to increase the efficiency of the tread device in complicated geological and technical conditions, that is, to reduce the negative effects of carbon dioxide corrosion, salt and paraffin deposits without additional wear of the magnesium electrode.

This goal is achieved in that the device for preventing corrosion of downhole equipment containing a protective housing, an electrode, perforated insulators, and couplings, characterized in that the electrode is made integral, the upper part of which is made of steel and screwed into a magnesium rod placed in a sealed lower housing, centered by a dielectric retainer, and filled with an electrolyte, for example 25% NaCl solution, the tightness of the composite electrode is provided by the upper and lower sealing glands and, the bottom of the lid contains a drainage plug.

The proposed design eliminates the negative influence of the corrosive medium on the pump design and creates conditions for ensuring electrochemical reactions in the sealed device case, prevents deposits of oil emulsions on the working surface of the magnesium electrode, while maintaining the cathodic polarization conditions of the downhole equipment.

In FIG. depicted the inventive device for preventing corrosion of downhole equipment.

A device for preventing corrosion of downhole equipment includes a steel electrode 1, pipe 2, couplings 3, magnesium rod 4, body 5, upper sealing gland 6, mounting ring 7, lower sealing gland 8, dielectric centralizer 9 with holes 10, bottom cover 11, drainage plug 12, the internal cavity A of the device will be filled with a lift fluid, and the cavity B is pre-filled with an electrolyte, for example, 25% NaCl solution.

A device for preventing corrosion of downhole equipment operates as follows.

After installing the borehole tread below the sucker rod pump (SHG) filter, the flow of lift fluid to the pump is provided through the inlet windows of the nozzle 2, excluding the passage of fluid through the active zone of the tread device, protecting it from mechanical wear and chemical dissolution. Under the influence of an electric field formed using a chemical current source Fe - Mg, in the mineralized water emulsified in oil, tread protection of the pumping equipment will be provided, at the same time, due to secondary electrochemical reactions on the metal surfaces of the device and pumping equipment, including the casing, electrically charged gas bubbles that prevent the formation of paraffin hydrate deposits on the walls of the pump casing and pipes and facilitate their separation. In turn, the viscous friction of the elevated flow is reduced and a gas-liquid medium is created with a density of lower liquid density in the annulus. By changing the geometric dimensions of the electrode (diameter and length, quantity and concentration of electrolyte), the efficiency and duration of the cleaning and prevention of corrosion and corrosion deposits on the surfaces of the deep pump equipment and casing are regulated.

Information sources:

1. Oilfield equipment; Handbook / Ed. EI Bukhalenko, - 2nd ed., Rev. and add. - M .; Nedra, 1990 .-- 559 p .; silt.

2. Patent No. 2,303,164, C1. Published July 20, 2007, BI No. 20.

Claims (1)

A device for preventing corrosion of downhole equipment, comprising a protective housing, an electrode, perforated insulators and couplings, characterized in that the electrode is made integral, the upper part of which is made of steel, the lower part of the electrode is screwed into a magnesium rod placed in a sealed lower case centered by a dielectric clamp and filled with electrolyte, the integrity of the composite electrode is provided by the upper and lower sealing glands, the bottom of the lid is provided with a drain ruyuschey stopper.