SU77197A1 - Instrument for determining reservoir pressure in wells - Google Patents

Description

Gauge depth measuring instruments are already known, provided with an open bottom and a closed top tube, in which air is compressed by the pressure of a column of water entering the tube to a height corresponding to the external pressure.

The proposed device {see drawing) is different from the known ones. The PSN consists of a housing /, a plug 2 into which a bottom 5 with a tube 4 and a cap 5 is screwed. a tube 6 with a tip 8. A gland 7 serves to seal the tube 6.

Before measurement, bottom 3 is filled to the brim with oil or oil. Then the device on the cable is slowly lowered into the well. When the device reaches the water surface, the tube through the tube 4 and the cap 5 penetrates into the instrument and enters the bottom 3. At the same time, the oil floats up, the air from the instrument begins to exit through the tube 6 until the water level in the instrument (Compared with the lower end tubes 6. With further lowering30 Code. Issue 10, 1949.

The scientific research institute of the device, the remaining air in it with a volume of Vo will be compressed with water according to the Boyle-Mariott law,

R.V, P, V ,, where:

Vi is the air volume in the device at pressure P;

PI is the desired pressure;

jPo - atmospheric pressure (10 m water column);

Vo is the volume of air remaining in the device,

the value of which is predetermined and on a scale can be counted on the outer surface of the casing 14 according to the position of the hole in the tip 8 of the tube 6.

The tube 6 may be raised or lowered before measurement, depending on the depth to which the device is to be lowered.

In addition to the digits of the corresponding volume, the cover can be engraved with numbers corresponding to the depth ranges.

When the device reaches the maximum depth, all the air from the body / will be squeezed out into the tube with water //. When filling tube 11, oil or oil, located on the surface of the water, wet the rail W.

465

Removing the device to the surface, unscrew the plug 12, remove the rail 10 and measure the drain on it, which is not wetted with oil. The product of the length of this teaching (stk) to the cross section of tube 11 (minus the cross-sectional area of the slats) will give the value of the airflow Ub to which the initial bopp of the above-mentioned Boyle-Mariott mule was compressed and the reservoir pressure is determined:

At p.

R.

P J.lA// /

Where:

/.- length of the non-wetted part

slats ./0; / is the section area of the tube 11.

In order to reduce the pressure of the device pulling piece onto the surface of the foam formed, it could not splash the rail 10, a mesh 13 is soldered into the lower part of the tube.

The resultant formation pressure determination should be corrected for temperature. For this purpose, it is necessary to suspend a closed thermometer from the instrument, which will indicate the temperature of the wellbore point where the reservoir pressure was determined.

Since, according to the Gay-Lussacs law, a change in volume by a constant pressure from an increase in temperature

by 1 ° Knock "h, it is. On, from

273

values need to subtract the increase in volume due to the increase in temp

 1 fo

-1/1 temperature equal to

273

Then the calculated pho view:

1/0 PO /,,

R.

/ V tt

 Io

 i (l +

273

subject matter

Claims (2)

1. An instrument for determining reservoir pressure in wells, provided with a closed at the upper end and an open at the lower measuring tube, in which air is compressed by the pressure of a water column entering the tube under the action of external pressure at a height corresponding to this pressure, which is only By the fact that, in order to control the volume of air compressed in the tube, the tube is mounted into the dividing body of the device into two parts, a partition into which the height-adjustable air outlet tube is inserted. 2. In the device of clause I, use a rail inserted into the measuring tube and intended to determine the volume of compressed air by its non-wetted end.