Frequency Analysis of Drilling Signals for Directional Control

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Solution Overview

Problem

Directional drilling in oil and gas wells is hindered by the time-consuming process of adjusting toolface angles and the challenges of static frictional forces, particularly in deep wells, which increase drilling costs and reduce efficiency.

Innovation Solution

The method involves transforming surface sensor measurements from time domain to frequency domain data to adjust rotary drilling parameters such as rotation rate, weight on bit, and drilling fluid flow rate, allowing for directional control without slide drilling and reducing axial vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If slide drilling is used to change drilling direction, then directional control is achieved, but static frictional forces between drill string and borehole wall increase, making it difficult to adjust toolface angle and maintain weight on bit

Engineering Contradiction:

Improvetoolface angle adjustmentVSAvoidstatic frictional forces

Core Design Contradiction:

Ease of operationVSForce

Solution Approach 1:

The patent replaces the mechanical slide drilling system with a rotary drilling system that uses frequency analysis of vibrations to control directional drilling. Instead of relying on mechanical friction between the drill string and borehole wall, the system uses rotational movement combined with vibration frequency monitoring to achieve directional control, thereby eliminating the static friction problem.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operational parameters from static slide drilling to dynamic rotary drilling with varying frequencies. By analyzing vibration frequencies in different ranges (first frequency range for directional control, second frequency range for weight on bit control), the system dynamically adjusts drilling parameters to maintain optimal control without experiencing static friction limitations.

Inventive Principle:

Principle #35Parameter changes

2Loss of information

If toolface angle is communicated via low bandwidth mud pulse telemetry, then directional information is transmitted, but the adjustment process becomes highly time consuming

Engineering Contradiction:

Improvetoolface angle communicationVSAvoidtoolface angle adjustment time

Core Design Contradiction:

Loss of informationVSLoss of time

Solution Approach 1:

The patent replaces the mud pulse telemetry communication system with a surface-based vibration analysis system. Instead of transmitting toolface angle information through the drill string using low-bandwidth mud pulses, the system monitors vibrations at the surface during rotary drilling, eliminating the need for downhole communication and dramatically reducing the time required to obtain directional control information.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system uses the drilling operation itself to generate the control information. By analyzing vibrations produced during rotary drilling, the system self-determines the toolface angle and drilling conditions without requiring separate communication systems or additional downhole sensors, thereby eliminating transmission delays.

Inventive Principle:

Principle #25Self-service

3Stability of the object's composition

If rotary drilling is used to maintain current drilling direction, then directional stability is achieved, but the ability to change drilling direction is limited compared to slide drilling

Engineering Contradiction:

Improvedrilling direction stabilityVSAvoiddrilling direction change capability

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic control to rotary drilling by utilizing vibration frequencies. Instead of static rotary drilling that maintains a fixed direction, the system applies controlled vibrations at specific frequencies to enable the drill bit to interact with the formation in a way that allows directional changes while maintaining rotational movement. This dynamic approach combines the stability of rotary drilling with the directional change capability of slide drilling.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent employs periodic vibrations at specific frequency ranges during rotary drilling to achieve directional control. By applying periodic vibrational forces to the drill string, the system creates controlled interactions with the borehole wall that enable directional changes while maintaining the overall rotary drilling process, thus combining directional stability with adaptability.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS10487642B2Frequency analysis of drilling signals

Publication Date: 2019.11.26 SCHLUMBERGER TECH CORP

AI summary

A method for directional drilling a subterranean borehole includes transforming surface sensor measurements from time domain sensor data to frequency domain sensor data. A rotary drilling parameter may be changed when a parameter of the frequency domain sensor data reaches a threshold or is within a predetermined range of values.