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Non-invasive technique for in-situ expansion and/or shrinkage measurement of cement

IP.com Disclosure Number: IPCOM000234599D
Publication Date: 2014-Jan-21
Document File: 6 page(s) / 566K

Publishing Venue

The IP.com Prior Art Database

Abstract

A significant change in the physical volume of the set cement in an annulus, be it an excessive reduction (shrinkage), or an excessive increase (expansion), can play a major role in the success or failure of long-term wellbore annular isolation. Although a wide variety of tests and devices have been developed in an effort to determine both the type and amount of expansion/shrinkage that occurs, current methods suffer from some deficiencies, including those that only give single-point data, and those that cannot perform quantitative testing in a non-invasive fashion. The purpose of this invention is to introduce a new laboratory measurement technique called Gamma Ray Tomography (GRT) to measure the expansion and/or shrinkage of the cement system in-situ and non-invasively while the specimen to be measured is maintained at downhole conditions of temperature and pressure. GRT has been used extensively for void fraction, soil structure determination and phase concentration distribution measurements in two-phase flow systems such as two-phase horizontal pipe flows, trickle bed reactors, and bubble columns.

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Page 01 of 6

Non-invasive technique for in-situ expansion and/or shrinkage measurement of cement

Abstract

A significant change in the physical volume of the set cement in an annulus, be it an excessive reduction (shrinkage), or an excessive increase (expansion), can play a major role in the success or failure of long-term wellbore annular isolation. Although a wide variety of tests and devices have been developed in an effort to determine both the type and amount of expansion/shrinkage that occurs, current methods suffer from some deficiencies, including those that only give single-point data, and those that cannot perform quantitative testing in a non-invasive fashion. The purpose of this invention is to introduce a new laboratory measurement technique called Gamma Ray Tomography (GRT) to measure the expansion and/or shrinkage of the cement system in-situ and non-invasively while the specimen to be measured is maintained at downhole conditions of temperature and pressure. GRT has been used extensively for void fraction, soil structure determination and phase concentration distribution measurements in two-phase flow systems such as two-phase horizontal pipe flows, trickle bed reactors, and bubble columns.

Description of the Invention

Tomography is derived from two Greek words "tomos", meaning "to cut or section" and graphein, meaning "to write". Tomography is a non-intrusive and non-invasive technique for imaging the interior of an object. This technique measures the spatial distribution of a physical quantity of the phases present in the area of interest. It is done by imaging the object from either transmission or reflection data collected by illuminating it from many different directions. The current system brings about value added changes in the current API expansion/shrinkage measurement to carry out dynamic in-situ volumetric change measurement in oil well sealants, while respecting and maintaining the industry standards. Figure 1 shows the schematic of high resolution gamma ray computed tomography system that can be used for the scanning of the required geometry or system.


Page 02 of 6

Figure 1:

Schematic of

high resolut

ion Gamma R

ay Compute

d Tomograph

y System

modules list

t pages.

he Gamma R

ted below. D

ay Tomogra

etail descr

phic Scann

iption

ing

Figure 2 of each o


1. API Ex


2. Autocl


3. Source

shows the
f these mod

pansion/Sh

ave

, Detectors

current syst

ules is disc

rinkage Mol

and Data A

em which in

ussed in the

d

cquisition S

cludes the

subsequen

ystem for th

A

utoclave

Data Ac

cquisition Sys

stem

D

De

tector

API Exp

ansion/Shrin

kage Mold 

Gamm

a Ray Source

 

Figure 2: S

chematic of c

urrent set-up


Page 03 of 6

API Expa

nsion/Shrin

Standard

retaining inner ring

cement f

outer spl balls, wit

standard

API mold c

bolt. After

and the ou

rom the spli it ring, one e

h a microm

API expans

kage Mold

ontains ma

assembly o

ter circular t; grease is

ach on eith

eter, is an ion/shrinkag

, Figure 3, b

sample is f

ough the ho...