Title: Distributed measurement of minimum and maximum in-situ stress in substrates

Abstract

A system for performing distributed measurements of in-situ stress includes an expandable element with at least one fiber optic sensor. The expandable element can be positioned at various depths in a hole in a substrate. A pressurizing device expands (and contracts) the expandable element when the expandable element is inserted in the hole in the substrate to exert pressure on the hole wall. A pressure sensor provides a sensor output indicative of a pressure applied to the hole wall by the expandable element. The fiber optic sensor and an optical interrogator measure strain along a length of the sensor in a continuous, high spatial resolution manner Based on the measured strain and pressure sensor output, the system determines various properties of the substrate such as, minimum principal stress, maximum principal stress, and/or principal stress direction associated with one or more fractures in the substrate, as well as substrate modulus.

Inventors:

Ohanian, III, Osgar John; Vandenberge, Daniel R.; Davis, Matthew Anthony

Issue Date:

2021-06-01

Research Org.:

Luna Innovations, Roanoke, VA (United States); Tennessee Technological Univ., Cookeville, TN (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1824024

Patent Number(s):

11022717

Application Number:

16/114,376

Assignee:

Luna Innovations Incorporated (Roanoke, VA); Tennessee Technological University (Cookeville, TN)

Patent Classifications (CPCs):

E - FIXED CONSTRUCTIONS E21 - EARTH DRILLING E21B - EARTH DRILLING, e.g. DEEP DRILLING

G - PHYSICS G01 - MEASURING G01L - MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE

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E - FIXED CONSTRUCTIONS E21 - EARTH DRILLING E21B - EARTH DRILLING, e.g. DEEP DRILLING

E21B47/06 - Measuring temperature or pressure
E21B49/006 - {Measuring wall stresses in the borehole

G - PHYSICS G01 - MEASURING G01L - MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE

G01L1/243 - {using means for applying force perpendicular to the fibre axis}

G - PHYSICS G01 - MEASURING G01N - INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES

G01N2021/4735 - {Solid samples, e.g. paper, glass}
G01N21/47 - Scattering, i.e. diffuse reflection

G - PHYSICS G01 - MEASURING G01V - GEOPHYSICS

G01V8/16 - using optical fibres

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DOE Contract Number:  

SC0015129

Resource Type:

Patent

Resource Relation:

Patent File Date: 08/28/2018

Country of Publication:

United States

Language:

English