SU1231215A1 - Method of measuring well depth - Google Patents

Description

" one

The invention relates to geophysics, in particular, to methods for determining the coordinates of the bottom hole.

The purpose of the invention is to improve the accuracy of measuring the depth of the well.

The essence of the method is that the depth of the well is determined from the ratio of the time of propagation along the string of pipes of longitudinal and transverse oscillations excited at the bottom of the well And recorded at its wellhead. The method is based on the fact that longitudinal and transverse acoustic waves are formed in the column. For single-phase elastic solids, to which a drill string can be equated with a sufficient degree of accuracy, the expression for the acoustic signal propagation speeds has the form for a longitudinal wave

 P v p for transverse wave

(one)

v .- (

547) (2)

| U - elastic La constant

where l and

p is the density of the material. Taking into account the well-known relationship between the elastic Lame constants, it is possible, after a series of transformations, to obtain a formula for determining the well depth based on the propagation time of elastic longitudinal and transverse oscillations from bottom to top.

 g

wells:

|.

 P) f4i

rr f / TTl

op T. Miteiko 2547/38

Compiled by V. Sidorov Tehred I. Gaidosh

Cor Pod

Circulation 548 VNIIGO1 State Committee of the USSR

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Design, 4,

31215

Where

t. t, E - P is the time of propagation of the longitudinal wave of oscillations from the bottom to the wellhead; the propagation time of the shear wave oscillations from the bottom to the wellhead; elastic modulus; pipe material density; well depth.

 ten

The method is implemented as follows.

At the bottom of a well, a discrete or continuous acoustic signal is excited in one way or another, which is transmitted through rocks, drilling mud and a string of pipes to the wellhead. Due to the higher density and uniformity of the pipe material, the signal that propagates through the pipe string is perceived at the wellhead as the highest in intensity and reflective in phase. For this purpose, sensors are used - magnetostrictive, piezoelectric, etc.

The values of t, and t are obtained by measuring the time between the beginning of the reference pulse and the time of the first arrival of the longitudinal and transverse waves. The p value is determined for a given pipe material by reference or by measuring and weighing the pipe, which can also be carried out at the well.

The economic effect is achieved due to the greater durability and reliability of the device implementing the method.

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Claims (1)

METHOD FOR DETERMINING A WELL DEPTH, including registration at the wellhead of elastic vibrations excited at the bottom of a well and transmitted along a pipe string, with the aim of determining the propagation time of longitudinal and lateral vibrations from the bottom to the wellhead, and the depth of the well is found by the formula where t ₍ is the propagation time of the longitudinal wave of oscillations from the bottom to the wellhead; t ₂ - the propagation time of a transverse wave of oscillations from the bottom to the wellhead; E is the modulus of elasticity; P is the density of the pipe material; 1 - well depth. * 12