SU1350644A1 - Central electrode of shielded-electrode logging - Google Patents

Abstract

The invention relates to the field of well logging using three-electrode side logging. The aim of the invention is to improve the reliability of the insulation and, as a consequence, the accuracy of measuring the electrical resistance of rocks. The central side logging electrode contains a housing with an electronic unit placed in it, a current-conducting sleeve mounted on the housing and connected to the electronic unit, a sleeve stroke limiter and an elastic shell of the housing. In this case, the conductive sleeve is made with side holes and annular and longitudinal grooves and is connected to the s-block by means of a conical candle. 1 il. (L made about 4 {

Description

The invention relates to geophysical surveys of drilling wells with a three-electrode side logging (BF) method for measuring apparent, p resistivity of the rocks intersected by the well,

The purpose of the invention is to increase the reliability of the insulation and the accuracy of measuring the apparent electrical resistance of rocks.

The drawing shows the central electrode of the side logging (CEBK) „

The electrode includes a housing 1, a current-conducting sleeve 2 mounted on the housing, a wire 3, a conical candle 4 sealing the electrically insulating monolith-sheath 5, a transformer 6, an electronic unit 7 and a nut 8 limiting the stroke of the sleeve 2. Pressing the insulating sealing monolith 5 is made through the holes A in the sleeve 2 in a special mold. Fixing the conductive sleeve 2 in the mold from the longitudinal movement during the insertion of the insulating sealing monolith is carried out by annular grooves B and C, and from turning by a longitudinal groove G.

CEBK works as follows.

In the study of drilling wells by electrical methods, a remote electrode, located 20 meters or more above the instrument case, on which the CETC is located, creates a field with a frequency of 300-400 Hz through the rock that composes the wellbore walls. Since case 1 of the TSEBK is galvanically and mechanically integral with the case of the device including the CEBK, through the conductive sleeve 2 of the CEEB, wire 3, the spark plug 4, due to the isolation of the sleeve from the case by the pressed insulating monolith 5, and the formation rocks opposite the sleeve current flows through the primary winding of the transformer 6. The result of this is

In the transformer winding circuit, an electrical signal is supplied to the electronic unit 7, which, after conversion, is fed to a telemetering system.

The nut 8 limits the possible mechanical movements of the conductive sleeve and protects it from damage during measurements.

When pulling the device along the well, it is in the medium of drilling fluid under pressure up to 1500 kgf / cm. Under these conditions, the rubber monolith 5, bounded by a nut 8, isolates the conductive sleeve 2 from the housing 1, the electric wire 3 and the conical candle 4 from the well fluid and, as a result, from a short to the body circuit. A cone candle 4 protects the cavity of the body 1 from penetration of drilling mud into it during mechanical damage to the rubber monolith.

Thus, due to the high reliability of the insulation, the measurement accuracy of the apparent resistivity of rocks is improved.

Claims (1)

Invention Formula The side runner's central electrode, comprising a housing with an electronic unit placed in it, a conductive sleeve mounted on the housing and connected to the electronic unit, a sleeve stroke limiter, and an elastic shell of the electrode housing, in order to improve the accuracy of measuring the apparent electric current. the resistance of rocks by means of increasing isolation reliability, the cable guide sleeve is made with side holes and annular and longitudinal grooves and is connected to the electronic unit through a rod a sleek candle. 623  5 G S B R eight G7