RU2302513C2 - Method for reagent injection in well - Google Patents

Abstract

FIELD: oil and gas production, particularly for metered corrosion inhibitor, paraffin and salt accumulation inhibitor, as well as demulsifying agent injection in oil well.

SUBSTANCE: method involves performing periodic regent supply in hole annuity of well with the use of proportioning pump. In the case of underground repair of sticky well supply cable of centrifugal pump electric motor is substituted for cable with capillary pipe. The cable with capillary pipe is connected to flow string and is lowered in well. Chemical reagent is injected in well via the capillary pipe to downhole pump inlet or within perforation interval of the well. To provide chemical reagent supply capillary pipe end is connected with polyethylene capillary pipe having design length with the use of connection nipple provided with weighting jet.

EFFECT: provision of guaranteed reagent supply to pump inlet or within well perforation interval, possibility to change class of reagent to be supplied in well and amount of reagent in dependence of well operation parameters.

1 dwg

Description

The invention relates to the oil and gas industry, in particular to methods for dispensing corrosion inhibitors, paraffin deposits, scaling and demulsifiers into oil wells, and is intended to improve the protection efficiency of oil and gas equipment.

A known method of dispensing a reagent into a well (1), comprising periodically injecting a reagent into the annulus and supplying it through a dispensing unit to a stream of well production extracted from a tubing string to a pump, the reagent is supplied through a dispensing unit by continuously transferring part of the product from tubing columns through a calibrated channel made in the tubing string above the dynamic level of the borehole fluid, and as a metering unit Use uncoupler for tubular space defined consistently with a gap relative to each other annular elements of elastic material, wherein the thickness of the ring members are selected not exceeding the size of the gap, and their diameter is selected not smaller borehole diameters.

The disadvantages of this method is the small penetration of fluid into the well, the inability to supply reagents to the bottomhole zone, the difficulty of dispensing reagents into the well.

There is also a known method of supplying reagents to the well (2), which includes descent of the dispenser to the bottom of the pump and tubing, periodically pumping the reagent into the dispenser through an armored hose and supplying the reagent to the liquid.

The disadvantages of this method is the inability to control the flow of the reagent in the process of pumping formation fluid, the check valve is in the well, which increases the risk of an accident.

The aim of the invention is to ensure the guaranteed flow of the dosed reagent to the pump intake or perforation interval of the well, the possibility of changing the brand of the dosed reagent and its dosage without raising the downhole equipment, as well as adjusting the dosage of the reagent depending on changes in the parameters of the well (flow rate, water cut, formation water characteristic etc.).

The goal (task) is achieved by the fact that in the method of supplying the reagent to the well, which includes periodic supply of the chemical reagent to the annulus of the well / dosing pump /, according to the invention, the supply of the chemical reagent is carried out through the capillary channel of a special ESP power cable, and the flow is carried out either in the interval perforation of the well, or at the reception of a well pump.

The drawing shows a schematic diagram of a method of supplying reagents to the well. A special power cable is produced by the Ufa cable production department of the ESP of the Neftekamsk oilfield equipment plant according to TU 3542-018-00147275-2003 and consists of parallel or twisted round conductors with an insulating sheath for supplying electric energy to the engine, a capillary channel formed by an insulating sheath.

The method of supplying reagents is as follows. At the wellhead, a tank with a chemical reagent 1, a metering pump 2, a pressure gauge 3, and an adjusting valve 4 are installed. In the lemmon box 5, the end of the capillary tube of a special cable 6 is connected to the adjusting valve 4 of the metering pump 2. The metering tank is filled with a chemical reagent and using the metering pump dosing of the selected reagent into well A at the perforation interval of reservoir B.

Depending on the task, the dosing of the chemical reagent is carried out either in the interval of perforation in the reservoir B, or at the reception of the well pump 9.

During an underground repair of a complicated well, the power supply pipe of the ESP electric motor is changed to a special cable with a capillary tube 6 and lowered on the NKT-7 string into the well 8. When a chemical is supplied, a polyethylene capillary tube 11 of the estimated length is connected using the connecting cable to the end of the cable capillary tube the nipple 10 with the load-nozzle 12. The load-nozzle provides a reliable descent of the polyethylene tube under the liquid level.

During the operation of the ESP, the well flow rate, dynamic level, current load on the electric motor are controlled. With the right choice of chemical reagent, the performance of a well pump improves.

This reagent dosing technology allows you to quickly change the reagent dosage, grade and supply interval in the well, makes it possible to save an expensive chemical reagent by delivering the chemical directly to the desired injection point with the most effective dosage.

With this technology, the reagent is not spent on saturation of the oil column in the annulus, its adsorption on the surface of the casing and tubing. Recommended for use according to the proposed technology, inhibitors of ASPO SNPCH-7941, 7920, corrosion inhibitors SNPCH-1004, SONPAR-9801, demulsifiers with corrosion inhibiting and bactericidal properties of Reapon-IF.

Information sources

1. A.S. 1810498 A1, "Method for dispensing a reagent into a well", 04/23/1993.

2. A.S. 883343 A1, "Device for supplying reagent and water to the bottom of the well", 11.23.1981.

Claims (1)

A method for supplying a reagent to a well, including a periodic controlled supply of reagent to the annulus of the well with a dosing pump, characterized in that during underground repair of a complicated well, the power cable of the centrifugal pump motor is changed to a cable with a capillary tube, which is lowered onto the tubing string into the well and chemical reagent is supplied through its capillary channel, while the supply is carried out either at a well pump or in the interval of perforation of wells others, for which a polyethylene capillary tube of the calculated length is connected to the end of the cable capillary tube using a connecting nipple with a nozzle load.