SU738523A3 - Device for measuring pressure in drill well - Google Patents

Abstract

1511513 Pressure gauges SPERRY-SUN WELL SURVEYING CO 6 May 1975 [6 May 1974] 18956/75 Heading G1L Borehole pressure change rates are measured by pumping fluid down a small bore tube 29 to a much larger diameter chamber 27 having a volume greater than that of the tube and situated at the depth of the hole where pressure is to be measured, the base of the chamber communicating with the borehole environment. The chamber may be a simple tube with which the tube 29 communicates through a filter (42), Fig. 2 (not shown) at the top or an annular chamber 50 may surround the borehole pipe.

Description

(54) DEVICE FOR MEASURING THE PRESSURE IN THE DRILLING WELL

one

The invention relates to the field of drilling research:

A device for measuring pressure in a borehole, comprising a casing connected to a measuring unit, which is connected to a pressure source, and a probe installed at the bottom of the borehole, the probe connected by means of a manometric tube with measuring unit 1, is known.

The disadvantage of this device is the periodic measurement of pressure, which is not only difficult, but also takes a lot of time because of the need to introduce equipment into each borehole with each measurement.

The purpose of the device is to simplify the design and improve the measurement accuracy.

This goal is achieved due to the fact that the probe is made with holes for communication with the borehole, is installed in the lower part of the casing and is rigidly connected with the manometric tube.

FIG. 1 depicts a well and production equipment for production (including a pressure measurement system according to the present

invention), a partial section; in fig. 2 pressure measurement equipment located within the borehole; in fig. 3 variant of equipment for measuring pressure B inside the well; in fig. 4 is a graph of pressure measurement from the time in the device.

The device includes a casing 1 with perforation 2 at the lower end for receiving 10 NIN of fluid from the rock.

Claims (2)

A string of 3 pipes extends from the beginning of the well (at the surface) to its lower end. Spacing nozzles 4 for centering are provided in the pipe string; in the well. A mandrel 5 is attached to the lower end of the tubing string to place the probe 6, which measures the pressure in the well. The probe 6 is installed in the mandrel at the lower end of the pipe string. A manometric tube 7 emerges from the probe to measure pressure. It is located on the outer surface of the column 3 of the pipe and extends to the surface of the earth, the output through the fitting 8 to the pressure gauge 10, to which a source 9 of a liquid under pressure is connected, which can 37 be, for example, a gas cylinder with a douche gas, designed to measure the rate of pressure change when charging a system with pressure. The speed can be measured by any device measuring pressure as a function of time. Since the pressure is applied relative to time or is expressed as a sequence over time, it is possible to determine the rate of change of pressure. One embodiment of probe b is shown in more detail in FIG. 2. The probe 6 used inside the well is a closed chamber with openings through which the fluid communicates with the intra-cavity. The upper end of the manometric tube communicates the probe with the surface. The filter 12, which may be made of a porous material, prevents foreign bodies from entering the probe into the manometer tube 7 or vice versa. Holes 13 are provided in the bottom of the probe for entry and exit of drilling fluid. FIG. 3 shows another variant of the underground probe. Around the column 3 pipes concentrate; if there is a shell 14, the upper and lower ends attached to the column. A chamber 15 is formed between the shell and the column 3, which communicates at the upper end with the surface through the filter 12 and the manometric tube 7. The liquid from the borehole enters the chamber 15 through the holes 13 located in the lower part of the probe. Capacity of the probe , must exceed the capacity of the manometric tube connecting the probe with the device on the surface. Large capacity results in a reduction in the scale of the vertical movement of fluid flow in the casing chamber, due to pressure changes. The required capacity of the chamber is just that. It can be calculated by the formula Р-NJ WCiKO ТР and -h / iv.wH mp is the maximum pressure; -minimal pressure; - casing capacity; The ratio of the capacitance of the probe chamber to the bone of the casing can be expressed as follows: P-P 11 As a control fluid supplied by a pressure source, a number of fluids can be used, of which nitrogen has proved to be one of the most suitable in practice. The filling point of the casing or probe chamber can be adjusted by changing the pressure of the test fluid with the pressure of the pressure gauge 10. When the pressure curve of the test fluid is plotted against time, the characteristic image shown in FIG. 4, if the pipe and chamber are filled at a constant rate. The pressure will gradually increase from zero along the segment of the curve of FIG. 4 to peak. At this peak, the pressure of the control fluid reaches a value sufficient to displace fluid from the borehole from chamber 15 of FIG. 2). After the start of the displacement of the test well fluid, the pressure decreases. The borehole fluid is displaced from the chamber, the control fluid itself begins to flow out through the openings 13 in the probe 6, the pressure of the control fluid can no longer change. This is clear from a portion of the pressure curve. The system is blocked, after which pressure changes in the borehole can be read directly from the manometer 10. Formula of the Invention A device for measuring the pressure in the borehole containing a casing associated with a measuring unit that is connected to a pressure source, a probe, a manometric tube, measuring An assembly, characterized in that, in order to simplify the design and improve the measurement accuracy, the probe is made with holes for communication with the borehole, is installed in the lower part of the casing and is rigidly connected to anometom1) with a tube. Sources of information taken into account in the examination 1. US patent number 3712129, cl. E 2 B 47/06, 1973.