RU2369739C1 - Method of evaluation of static and dynamic levels of fluid in annular space of well equipped with electric centrifugal pump - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: invention refers to oil industry and can be implemented at survey of wells. The method of evaluation of static and dynamic levels of fluid in annular space of a well equipped with an electric centrifugal pump includes evaluating of levels by geo-physic methods. Prior to evaluation of levels a hole is made in a face plate. A perforated plastic pipe narrowed in its lower part and secured on external surface of a flow string is lowered together with the flow string and the pump into the well. Bottom of the plastic pipe is arranged 0.5-1.0 m above the pump; an upper end of the plastic pipe comes out to surface through the hole in the face plate. A gap between the plastic pipe and the hole of the face plate is leak proofed; a measuring tape with a level sensor is lowered inside the plastic pipe. Surface of fluid is contacted; a level is measured and the measuring tape is withdrawn out of the plastic pipe.

EFFECT: simplification of measuring procedure of fluid level.

Description

The invention relates to the oil industry and may find application in well research.

There is a method of determining the level in pipes rising through the formation tester during testing of a well, which comprises measuring the subcritical gas flow with a washer meter, a stopwatch and aneroid barometer-aneroid of air flow from the pipes and the absolute initial pressure in them (mm water), closing the washer and measuring the time of pressure rise in the pipes to the final value. After calculating the change in the volume of empty pipes as the product of air flow by the time the washer was closed, according to the Boyle-Mariotte law, the initial volume of empty pipes is determined, dividing them by their specific volume, the level in the pipes is determined (RF patent No. 2104395, published. 1998.02.10).

The known method is inaccurate due to indirect level determination.

Closest to the proposed invention in technical essence is a method for determining the static and dynamic fluid levels in the annular space of an oil well equipped with an electric centrifugal pump, including determining the levels by geophysical methods according to gamma-gamma measurements by a scattering density meter and a highly sensitive thermometer during the operation of the electric centrifugal pump. Before starting the electric centrifugal pump, an additional background measurement of a gamma-gamma-ray scattering densitometer is carried out, this measurement is compared with the measurement when determining levels during the operation of the electric centrifugal pump, and, based on the test results, it is concluded that there is oil or oil with foam gas in the range of discrepancies or no oil or oil with gas foam in the absence of discrepancies in the testimony (application for invention of the Russian Federation No. 2004125694, published. 2006.02.10 - prototype).

The method also provides for indirect determination of the level and requires the use of high-precision instruments of indirect measurement such as thermometry, the method is complex, multi-stage.

The proposed invention solves the problem of directly determining the level of fluid in the well, simplifying operations.

The problem is solved in that in the method for determining the static and dynamic fluid levels in the annular space of a well equipped with an electric centrifugal pump, including determining the levels by geophysical methods, according to the invention, a hole is made before determining the levels in the faceplate when the tubing string with the pump is lowered together with the string lower the perforated plastic pipe with a narrowing in the lower part, fixing it on the outer surface of the column, setting the bottom of the plastic pipe They are 0.5-1.0 m higher than the pump, the upper end of the plastic pipe is brought to the surface through the hole in the faceplate, the gap between the plastic pipe and the faceplate hole is sealed, a measuring tape with a level sensor is lowered inside the plastic pipe, contacted with the surface of the liquid, measured level and remove the measuring tape from the plastic pipe. The features of the invention are:

1) determination of levels by geophysical methods;

2) making holes in the faceplate;

3) during the descent of the tubing string with the pump, together with the string, the descent of the perforated plastic pipe, fixing it on the outer surface of the string;

4) a plastic pipe with a narrowing in the lower part;

5) the bottom of the plastic pipe is installed at 0.5-1.0 m above the pump;

6) the conclusion of the upper end of the plastic pipe to the surface through the hole in the faceplate;

7) sealing the gap between the plastic pipe and the faceplate hole;

8) descent inside the plastic pipe of the measuring tape with a level sensor;

9) contacting with the surface of the liquid;

10) level measurement;

11) removing the measuring tape from the plastic pipe.

Sign 1 is common with the prototype, signs 2-11 are the salient features of the invention.

SUMMARY OF THE INVENTION

Existing methods for measuring the liquid level in the well are indirect or do not provide sufficient measurement accuracy, the methods are complex, multi-stage. The proposed method solves the problem of directly determining the liquid level in the well, simplifying operations, the problem is solved as follows.

Before determining the levels in the faceplate, a hole is made. When lowering the tubing string with the pump, the perforated plastic pipe is lowered along with the string with a narrowing in the lower part, fixing it to the outer surface of the string, for example, with straps, clamps, etc. The bottom of the plastic pipe is set 0.5-1.0 m above the pump. The upper end of the plastic pipe is brought to the surface through an opening in the faceplate. The gap between the plastic pipe and the faceplate hole is sealed, for example, by filling with sealant, inserting an internal expansion ring, etc. Inside the plastic pipe, the measuring tape with the level sensor is lowered, they are in contact with the surface of the liquid, the level is measured and the measuring tape is removed from the plastic pipe.

To beat the dynamic level, it is necessary that the well is in operation. To beat a static level, it is necessary that the well be idle. Due to perforation, i.e. drilled holes in the plastic pipe, filling the pipe with liquid is faster than the time required to restore or drop the level. Therefore, during the study, you can not take into account the filling time or the time of release of the plastic pipe from the liquid.

As a plastic pipe, polyethylene, polypropylene, polyvinyl chloride, fluoroplastic pipe, or a pipe from other thermoplastic polymers and their copolymers can be used.

The descent of the measuring tape outside the plastic pipe leads to the entwining of the tubing string and the cable on it and the inability to advance the tape either up or down.

The installation of the bottom of the plastic pipe 0.5-1.0 m above the pump contributes to the full coverage of all possible level changes in the well.

The diameter of the weight of the measuring tape is 14-16 mm. A sufficient inner diameter of the plastic pipe is 18-20 mm. To quickly fill the plastic pipe with liquid, holes with a diameter of 7–9 mm are drilled through it every 1-2 m. To prevent the weight of the tape with the tape falling into the hole when the tape breaks, the bottom of the pipe must be narrowed or may be partially extinguished. Concrete example

Determine the static liquid level in the annulus of a water well equipped with an electric centrifugal pump. The inner diameter of the casing is 154 mm. The outer diameter of the tubing string is 73 mm. The electric centrifugal pump of the ETsNV 5-8-100 brand should be placed at a depth of 70 m.

Before determining the levels in the faceplate, a hole with a diameter of 30 mm is made. When lowering the tubing string with the pump, the cable for pump power and the perforated plastic pipe made of polyethylene with an inner diameter of 20 mm, a wall thickness of 2.5 mm and with a narrowing in the lower part to a diameter of 8 mm are lowered together with the string. The plastic pipe is equipped with holes with a diameter of 8 mm every 1.5 m. Fasten the plastic pipe every 2 m on the outer surface of the column with straps. The bottom of the plastic pipe is set 0.7 m above the pump. The upper end of the plastic pipe is brought to the surface through an opening in the faceplate. Seal the gap between the plastic pipe and the faceplate hole with sealant. Inside the plastic pipe, the measuring tape of the USK-TE type electric contact level gauge with an electrode and a weight is lowered. When the water level in the borehole is fixed, sound and light signals appear on the electronic unit integrated in the level gauge. Contact with the surface of the liquid, measure the level and remove the measuring tape from the plastic pipe. Determine that the static fluid level in the well is at a depth of 40.85 m

Launch the well into operation. Power is supplied via cable to the electric centrifugal pump and water is pumped out of the well for 2 days. Inside the plastic pipe, the measuring tape is lowered, in contact with the surface of the liquid, the level is measured and the measuring tape is removed from the plastic pipe. Determine that the dynamic fluid level in the well is at a depth of 58.12 m.

Thus, it is possible to directly determine with high accuracy the static and dynamic fluid level in the well.

The application of the proposed method will allow to solve the problem of direct determination of the liquid level in the well and simplify the measurement operations. The proposal also allows for accurate monitoring of fresh stocks, including drinking, water when using it in the national economy.

Claims (1)

A method for determining the static and dynamic fluid levels in the annulus of a well equipped with an electric centrifugal pump, including determining the levels by geophysical methods, characterized in that a hole is made before determining the levels in the faceplate, when the tubing string with the pump is lowered, the perforated plastic pipe is lowered along with the tubing string with a narrowing in the lower part, fixing it on the outer surface of the column, the bottom of the plastic pipe is installed 0.5-1.0 m above the pump, hny end of the plastic pipe exteriorized through an opening in the faceplate, sealed gap between the plastic pipe and the hole chuck, inside the plastic tube is lowered metering tape with a level sensor in contact with the liquid surface level is measured and the measuring tape is removed from the plastic tube.