Drilling Impedance Model for Real-Time Rock Property Identification

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Solution Overview

Problem

Current methods for determining rock properties in the drilling industry are inaccurate, costly, and time-consuming, failing to identify depleted zones and abnormalities in real-time, leading to inefficient drilling and potential economic losses.

Innovation Solution

A method utilizing a mathematical model of a drill bit to determine rock properties such as compressive strength and porosity in real-time by correlating operational parameters like rate of penetration, weight on bit, and bit revolutions per minute, and using intrinsic drilling impedance to identify abnormalities and depleted zones.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If core sampling testing is used to determine rock properties, then measurement accuracy is improved, but cost and time consumption increase significantly

Engineering Contradiction:

Improverock property measurement accuracyVSAvoidtime consumption

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the mechanical core sampling system with a drilling impedance measurement system. Instead of physically extracting and testing core samples, the system uses sensors to measure drilling impedance parameters (torque, power, weight on bit) and calculates rock properties through mathematical models, eliminating the need for mechanical coring operations.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces drilling impedance measurements as an intermediary between the drilling process and rock property determination. The impedance parameters serve as intermediate variables that correlate with rock strength, allowing indirect but accurate measurement of rock properties without direct core sampling.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Loss of time

If wireline log interpretation is used to determine rock properties, then cost and time are reduced, but measurement accuracy and real-time identification capability deteriorate

Engineering Contradiction:

Improvetime consumptionVSAvoidrock property measurement accuracy

Core Design Contradiction:

Loss of timeVSMeasurement precision

Solution Approach 1:

The patent performs rock property determination during the drilling process itself, before the drilling equipment is disassembled. By measuring drilling impedance in real-time and calculating rock properties immediately, the system enables preliminary identification of rock characteristics and depleted zones while the drilling rig is still positioned at the well site.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements real-time feedback by continuously monitoring drilling impedance parameters and immediately calculating rock properties. This feedback loop allows operators to identify depleted zones and abnormalities during drilling, enabling timely adjustments to drilling parameters or equipment configuration based on actual rock conditions.

Inventive Principle:

Principle #23Feedback

3Measurement precision

If drilling equipment is brought back to the well after disassembly to identify depleted zones, then accurate identification is possible, but cost increases significantly

Engineering Contradiction:

Improvedepleted zone identification accuracyVSAvoidcost

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The patent performs depleted zone identification during the drilling operation before equipment disassembly. By calculating rock properties and identifying depleted zones in real-time using drilling impedance data, the system eliminates the need for costly re-mobilization of drilling equipment to conduct additional logging operations after the well is drilled.

Inventive Principle:

Principle #10Preliminary action

4Reliability

If drill bit is removed prematurely due to inability to identify abnormalities, then safety is improved, but productivity decreases

Engineering Contradiction:

Improvedrilling safetyVSAvoiddrilling efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent provides real-time feedback on drilling conditions through continuous monitoring of impedance parameters and calculation of rock properties. This immediate feedback allows operators to distinguish between normal variations and actual abnormalities or depleted zones, enabling informed decisions about whether to continue drilling or remove the bit, thereby avoiding premature bit removal while maintaining safety.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS8082104B2Method to determine rock properties from drilling logs

Publication Date: 2011.12.20 VAREL INT IND LP

AI summary

A method of identifying one or more rock properties and/or one or more abnormalities occurring within a subterranean formation. The method includes obtaining a plurality of drilling parameters, which include at least the rate of penetration, the weight on bit, and the bit revolutions per minute, and then normalizing these plurality of drilling parameters by calculating a depth of cut and an intrinsic drilling impedance. Typically, the intrinsic drilling impedance is specific to the type of bit used to drill the wellbore and includes using a plurality of drill bit constants. From this intrinsic drilling impedance, the porosity and/or the rock strength may be determined which is then compared to the actual values to identify the specific type of the one or more abnormalities occurring. Additionally, the intrinsic drilling impedance may be compared to other logging parameters to also identify the specific type of the one or more abnormalities occurring.