Directional Well Drilling Oriented Bent Sub

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Solution Overview

Problem

Existing directional drilling technologies face challenges in maintaining a straight borehole path due to tortuosity caused by delayed directional measurements and mechanical stress on orienters positioned close to the drill bit, leading to increased friction and reduced drilling distance.

Innovation Solution

A drilling assembly with a bent section terminating in a drill bit, suspended on coiled tubing, featuring an orienter with an electric motor and sensors positioned closer to the bit for real-time feedback, allowing continuous rotation to minimize tortuosity and reduce mechanical stress by distributing forces more evenly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the orienter is positioned close to the drill bit to reduce torque, then the torque required to rotate the motor and bent sub is reduced, but the bending moment on the orienter increases beyond acceptable limits

Engineering Contradiction:

Improvetorque required to rotateVSAvoidbending moment on orienter

Core Design Contradiction:

PowerVSStress or pressure

Solution Approach 1:

The patent transitions from positioning the orienter solely based on torque considerations to a multi-dimensional solution that includes an electric motor positioned in the bent sub to share the rotational load. This distributes the mechanical stress across multiple components and positions, resolving the contradiction between reducing torque requirements and minimizing bending moments.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The rotational function is segmented between two components: the orienter positioned away from the bent sub (reducing its bending moment) and an electric motor positioned in the bent sub (providing additional torque). This segmentation allows each component to operate within acceptable stress and torque limits simultaneously.

Inventive Principle:

Principle #1Segmentation

2Reliability

If sensors are positioned away from the drill bit, then they are easier to protect and position, but the feedback of hole position is delayed

Engineering Contradiction:

Improvesensor protection and positioningVSAvoiddelay in feedback

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent implements preliminary action by continuously rotating the bent sub with the orienter during drilling operations. This continuous rotation ensures that the bit drills away from the desired path equally in all directions, maintaining a straight hole path while the sensors positioned away from the bit still provide timely feedback through continuous monitoring.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The continuous rotation of the bent sub creates a spiral drilling pattern that effectively drills a straight hole. This continuous action compensates for the distance between sensors and bit, as the rotation ensures the bit remains on track despite the delayed positional feedback from sensors positioned away from the bit for reliability.

Inventive Principle:

Principle #20Continuity of useful action

3Shape

If the bent sub is continuously rotated to reduce tortuosity, then the borehole path becomes straighter, but the mechanical stress and friction forces increase

Engineering Contradiction:

Improveborehole straightnessVSAvoidfriction forces and mechanical stress

Core Design Contradiction:

ShapeVSForce

Solution Approach 1:

The rotational function is segmented between the orienter and an electric motor in the bent sub. This segmentation allows the bent sub to be continuously rotated at lower speeds and with distributed torque, reducing the instantaneous mechanical stress and friction forces while still achieving the desired straight borehole path through continuous rotation.

Inventive Principle:

Principle #1Segmentation

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

This configuration enables drilling of nearly straight holes with minimal tortuosity, reducing friction and mechanical stress, allowing for longer drilling distances and more accurate path control by providing immediate directional feedback and reducing the risk of mechanical failure.

Implementation Method 1

the orienter means includes an electric motor situated in the bent section

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the top section being suspended upon coiled tubing

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS8978784B2Directional well drilling

Publication Date: 2015.03.17 ANTECH

AI summary

A drilling assembly comprises a bent housing terminating in a drill bit (18), and a top section coupled to the bent section. The top section is suspended upon coiled tubing (10). The drilling assembly includes an orienter means (2-6) capable of rotating the bent housing with respect to the top section, wherein the orienter means includes an electric motor (34) situated in the bent section. The bent housing includes sensor means (30) for monitoring downhole physical variables, the sensor means being situated in the bent section. The orienter means may be an electro-mechanical motor.