Directional Core Drill Packer Pressure Control

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Solution Overview

Problem

Existing directional core drilling systems face challenges with maintaining consistent packer pressure independent of flow rate, requiring steady flow rates for pressurization, limited adjustment of toolface angles, and inadequate cooling of bearing elements, which complicates drilling operations and core sample collection.

Innovation Solution

Integration of a pressure-controlled valve in the core tube assembly to ensure consistent packer pressure, an instant counter-clockwise engaged coupling for toolface angle adjustment independent of fluid pressure, and a 3-point support arrangement for the eccentric bearing to allow tilt and maximize core sample diameter, along with direct exposure of trust bearings to drilling fluid for enhanced cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If a packer assembly is used to pressurize the drill bit in existing directional core drilling systems, then the drill bit can be pressedurized to achieve directional control, but the packer pressure becomes dependent on steady flow rate which limits operational flexibility

Engineering Contradiction:

Improvepacker pressureVSAvoidoperational flexibility

Core Design Contradiction:

Stress or pressureVSEase of operation

Solution Approach 1:

The patent replaces the fluid-pressure-dependent mechanical packer system with a motor-driven pressurization system. The motor directly drives the packer assembly through a transmission mechanism, eliminating dependence on steady flow rate and providing independent control over packer pressure. This mechanical substitution allows the packer to be pressurized regardless of drill fluid flow conditions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system incorporates a flow restriction device that automatically maintains a predetermined flow rate to the drill bit while the motor independently controls packer pressurization. This self-regulating flow restriction eliminates the need for external flow control operations, allowing the operator to focus solely on directional control through motor speed adjustment.

Inventive Principle:

Principle #25Self-service

2Productivity

If flow rate is increased to improve cooling and bit performance, then drilling efficiency improves, but packer pressure becomes unstable and directional control is compromised

Engineering Contradiction:

Improvedrilling efficiencyVSAvoiddirectional control stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent segments the drilling system into independent functional modules: a motor-driven packer assembly for directional control, a flow restriction device for stable flow rate maintenance, and a drill bit for cutting. This segmentation allows each component to operate independently at optimal parameters - the motor controls packer pressure for directional stability while the flow restriction device maintains consistent fluid flow for cooling and bit performance, eliminating the trade-off between productivity and control stability.

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If the drill string is rotated to adjust toolface angle in existing systems, then directional deviation can be corrected, but the operation becomes complex and time-consuming

Engineering Contradiction:

Improvetoolface angle adjustmentVSAvoidoperation complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces the traditional mechanical rotation method with a motorized adjustment mechanism. The motor-driven packer assembly can be rotated independently of the drill string rotation, allowing toolface angle adjustment through controlled motor movement rather than complex string rotation operations. This substitution simplifies the adjustment process and reduces operational complexity while maintaining adaptability for correcting directional deviations.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables reliable and efficient drilling with consistent packer pressure, easy adjustment of toolface angles, and improved cooling and sample size, reducing operational complexities and enhancing drilling performance.

Implementation Method 1

pressurization of a packer assembly (9) in a steerable core barrel assembly (1)

Methodology Applied

Scientific EffectFluid pressure: Pressure Increase

Implementation Method 2

direct exposure of trust bearings to drilling fluid for enhanced cooling

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP3710669B1A directional core drill assembly

Publication Date: 2021.10.13 HUYGENS AS

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AI summary

The present invention relates to directional core drilling operations in the bedrock, and in particular an apparatus and method for steering a core barrel in a pre-defined path and at same time collect core samples of the bedrock, using said core barrel. In particular the invention describes an apparatus and method for controlling the pressure applied to a packer assembly in said drilling system. More specifically to provide a device and method for the pressurization of a directional core drill packer assembly that ensure the packer pads are exposed to a predefined pressure regardless of flow rate. Furthermore a system that enables adjustment of the predefined pressure without pulling the drill to the surface as well as adjustment of the toolface in a steerable drilling tool where the down hole system presspressure is pre-defined to only one specific value.