SU732518A1 - Device for determining permeability of rock sample - Google Patents

Description

I

The invention relates to field geophysics and can be used to study the permeability of rock samples.

A device for determining the permeability of rocks is known, comprising an outer rigid body and an elastic inner chamber 1.

A device for determining the permeability of a rock specimen is known, comprising a housing, a working head with inlet and outlet fluid valves and an elastic sealing chamber made in the form of a cylindrical cup in which sample 2 is placed.

However, this device is not suitable for studying a hollow cylindrical rock sample, since the elastic chamber due to direct fit of the rock sample eliminates the possibility of radial filtration in it and creating an external uniform all-round load on it.

The purpose of the invention is to increase the determination accuracy with a uniform uniform load on the sample.

The goal is achieved by the fact that the chamber is annular, with the lateral surfaces of the chamber and the sample forming annular cylindrical channels that communicate with the inlet and outlet fluid channels 5 and are filled with granular material.

The drawing shows the proposed device, a longitudinal section.

The device includes a housing 1, a cover 2, a working head 3 with a supply 4 and a discharge channel 5, connected with 10 means for pumping fluid and measuring pressure and temperature (not shown). A retaining ring 6 is installed inside the working head. The device also contains an elastic annular chamber 7 inserted into a perforated cup 8, which with the working head and with the test hollow cylindrical rock sample 9 forms separated annular channels 10 and 11 filled with granular material with a known permeability which includes inlet and outlet channels. Between the cup 8 and the housing 1 there is a hydro-pressing chamber 12. The device also contains a gasket 13, grundbuksu 14.

Preparing the device for operation and determining the permeability of a hollow cylindrical rock sample is performed as follows. An extracted and dried hollow cylindrical specimen of rock with a flat end is pressed into the elastic chamber and pressed through a gasket to the end of the working head. Then, granular material is poured into the annular channels.

After that, the chamber with the rock sample and quartz sand in the annular channels is inserted into a perforated cup 8, which, after installing a head into it, inside which a retaining ring is installed at a certain level to prevent the elastic chamber from breaking through, is inserted into the body. Then, the packing book 14 is put on the working head. The lid of the chamber is pre-compacted and the ends of the specimen of the rock are pressed against the end of the working head and the bottom of the chamber.

The assembled device is connected to an apparatus or device for determining permeability.

A comprehensive uniform external load on a hollow cylindrical rock specimen, equal to the difference between rock pressure on the reservoir and intra-pore pressure in the reservoir, is created by injecting a fluid (with a press or pump connected to the body with line 15) into the hydro-pressing chamber. By means of an elastic chamber and a granular material with a known permeability, which is located in annular gaps, pressure is transmitted to the filter surfaces of the rock specimen.

After the device is heated to reservoir temperature, a certain amount of fluid (liquid or gas) is pumped through the rock sample 9 at a constant pressure drop. This completes the process for determining the permeability of the rock sample.

The main advantage of the device is that it increases the accuracy of determining the permeability of fractured rocks by providing an examination of hollow samples during radial filtration.

Claims (2)

1. USSR Author's Certificate No. 135277, cl. E 21 V 49/00, 14.11.60. 2. Core holder. Factsheet No. 597-74, North-Caucasian Interdisciplinary Territorial Center for Scientific-Technical Information and Propaganda, 1974 (prototype).