SU54862A1 - Pressure gauge for well pressure measurement - Google Patents

Description

The gauge of the proposed design is intended to study the pressure inside the wells under conditions when, in the presence of high pressure, mainly due to the high level of drilling mud, it is required to measure minor changes in this pressure caused by the absorption of drilling mud by individual layers and from the formations of drilling waters. The pressure gauge is lowered into the well, and its readings are transmitted to the surface using a normal carotene cable and recorded with normal carotene equipment. Thus, the pressure gauge is an additional tool for cartographic batches. In the manufacture of a device of small diameter and descent on the oil-resistant cable, the proposed pressure gauge can also be used in operational wells and serve to study the regime of reservoir pressure in the flowing wells.

The proposed pressure gauge is of the type known pressure gauges, working according to the method of partial compensation of the measured pressure using a piston and Bourdon

tube control electrical contact alarm.

A distinctive feature of the proposed pressure gauge is the use, as an organ creating back pressure, which compensates a part of the measured pressure, of a load suspended from the pressure gauge.

The proposed pressure gauge is shown in the attached drawing and consists of a steel cup 7, which is lowered onto a three-core cable 2 into the well. Inside the cup is chamber 3. connected to the pressure gauge 4. Chamber 3 and the tube of the pressure gauge 4 are filled with oil, which can be compressed by the pressure 5. This pressure is influenced by well pressure through the corrugated membrane cylinder b and the oil-filled cavity 7 of the glass.

Since the pressure in the wells reaches up to 300 atm., And the recording of the change in pressure must be carried out with an accuracy of one, and sometimes even a fraction of the atmosphere, it is advisable to record with a more sensitive manometer. Therefore, the apparatus provides for the installation of a 10-50 atmospheric pressure gauge with pressure relief by a counterweight in the form of a vessel 8 connected by a piston 9 to a piston 5- Pressure relief is performed when the arrow goes beyond the scale. For this purpose, the following device is used. As soon as the gauge needle 10 reaches the zero (left) position, this arrow presses the beam //, which turns slightly, thereby turning off the connection of the reichord 76 to the ground and connecting to the ground of the circuit 12 supplying the relay / 5. This relay opens the valve J4, through which the vessel 8 is unloaded. At the same time, the pressure on the piston 5 increases and the pressure gauge again comes to its maximum (right) position. In this case, the arrow moves to the right and, in its extreme position, presses the second arm of the rocker arm 77, as a result of which the rocker turns slightly clockwise and thereby turns off the relay (according to which the valve 7 closes) and turns on the chain of the reichord 76. Load 8 is filled with mercury or lead shot.

When the pressure in the well changes, the arrow W, moving along the rail / 6, includes a potential difference proportional to the pressure on the pressure gauge. This potential difference is transmitted through the wires W and L and is measured on the surface at the well by conventional carotene recording equipment.

The end of the measurement limit by the pressure gauge, the moment at which the reichord is turned off and the relay is turned on, is recognized by the change in current which, when passing through the reichord, has a much smaller value. Registering the moments of current change and stopping the pressure gauge on these sections before balancing it with a load, it is possible to construct a pressure change curve according to the data of the diagram segments.

Using the static pressure gauge in the flowing wells is carried out in exactly the same way. The pressure gauge is loaded with a somewhat large back pressure, which at the point of installation of the apparatus is discharged until the moment when the needle of the device leaves the zero position. To do this, it is enough to raise the device slightly above the test point and turn on the current, and then, when the pressure reaches its maximum, lower the device. Power is supplied through the wire L; the return wire is ground. During the descent, in order to avoid the premature opening of the valve 74, the apparatus is not powered by current and the descent is performed with the valve M closed.

When uniformly lifting the instrument, it is possible to open the valve 4 at the beginning of the lift and, choosing the nozzle diameter depending on the lift rate and the specific gravity of the drilling mud, gradually discharge the pressure along an inclined straight line that expresses the dependence of the hydrostatic pressure increase with depth. In this case, the manometer will register only deviations from the regular change in hydrostatic pressure caused by the reasons indicated at the beginning of the description.

The present pressure gauge also provides for: a) the ability to work during descent. In this case, instead of unloading the backpressure, there is a load by infusing, as opposed to mercury, from a tank located above the counterweight (the scheme is similar to that stated); b) replacing a load with a mercury nozzle of a series of lead weights connected to each other by conventional electromagnetic clutches that release and eject the load at times when, according to the attached diagram, current must be directed to the relay.

The subject matter of the invention.

1. A manometer for measuring pressure in wells, operating according to a method of partial compensation of a measured pressure, using a piston and a Bourdon tube, controlling an electrical contact signaling system, characterized in that, as a counter-pressure organ, compensating part