Telescopic Drill String for Thermal Expansion Compensation

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Solution Overview

Problem

Current formation testing methods face challenges in maintaining well control and compensating for thermal expansion and contraction of well strings during open hole formation testing, which can lead to mechanical damage and compromised seal functionality.

Innovation Solution

The proposed solution involves a formation testing assembly that includes a hydraulic bladder or packer to seal the well annulus, circulation of drilling mud to compensate for thermal expansion, and a method to adjust the well string length based on thermal changes, ensuring stable operation and accurate pressure measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If formation testing is conducted in open hole conditions, then production evaluation can be performed, but thermal expansion and contraction of well strings causes mechanical damage and seal compromise

Engineering Contradiction:

Improveseal functionalityVSAvoidthermal expansion damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system transitions from a static drill string to a dynamic system with a telescopic joint that can extend and retract to accommodate thermal expansion and contraction of the well string during formation testing operations

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the physical parameter of well string length dynamically through the telescopic joint mechanism, allowing the inner tube to slide within the outer tube to compensate for thermal dimension changes

Inventive Principle:

Principle #35Parameter changes

2Reliability

If well string length is fixed, then structural simplicity is maintained, but thermal expansion causes mechanical damage and seal compromise

Engineering Contradiction:

Improvemechanical integrityVSAvoidwell string structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The drill string incorporates a dynamic telescopic joint section with nested tubes that can change length, transforming the rigid fixed-structure into an adaptable system that responds to thermal conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The well string is divided into separate telescopic sections with inner and outer tubes that can move independently, allowing localized adjustment without affecting the entire string structure

Inventive Principle:

Principle #1Segmentation

3Reliability

If packer is used to seal well annulus, then well control is improved, but thermal expansion compromises seal functionality

Engineering Contradiction:

Improvewell controlVSAvoidthermal expansion damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The telescopic joint is pre-configured to compensate for thermal expansion before it occurs, allowing the inner tube to slide outward in anticipation of heat-induced expansion during mud circulation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses dynamic adjustment of the telescopic joint to maintain constant tension on the packer, ensuring continuous seal effectiveness despite thermal dimension changes

Inventive Principle:

Principle #15Dynamics

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 approach enhances well control and minimizes mechanical damage by accounting for thermal expansion and contraction, allowing for more accurate formation testing and reducing the risk of seal compromise.

Implementation Method 1

compensating for thermal expansion and contraction of well strings

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

circulation of drilling mud to compensate for thermal expansion

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS10087752B2Oilfield operation using a drill string

Publication Date: 2018.10.02 SCHLUMBERGER TECH CORP

AI summary

Collecting temperature data at a plurality of locations along a wellbore, performing thermo-mechanical simulations of a drill string in response to mud circulation wherein the drill string comprises a tool string suspended in the wellbore from a pipe string, determining changes in length of the pipe string due to temperature changes, positionally fixing the tool string at one of the locations, and adjusting the length of the pipe string based on the determined change in length of the pipe string. Positionally fixing the tool string may comprise lowering the drill string a side entry sub of the drill string is proximate a top end of the wellbore wherein the side entry sub is configured to allow a wireline cable to enter a bore of the drill string, positioning the side entry sub above a blow-out-preventer, and closing the blow-out-preventer around the drill string below the side entry sub.