Downhole Probe Perforator for Cased Borehole Evaluation

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Solution Overview

Problem

Current technologies face limitations in performing formation evaluation and perforation in cased boreholes, as existing tools are not adaptable for long-term use in various wellbore conditions and are prone to differential sticking and damage during conveyance, while also failing to effectively reach beyond the altered zone around the borehole.

Innovation Solution

A downhole tool with a probe assembly for sealing the borehole wall, a perforator capable of penetrating consolidated formations, casing, and cement, and a pump for fluid communication, designed for conveyance via wireline or drillstring, with a dual bit system for efficient perforation and fluid injection, and inflatable packers for sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing tools are used for formation evaluation in cased boreholes, then some formation testing can be performed, but the tools are prone to differential sticking and damage during conveyance

Engineering Contradiction:

Improvetool reliabilityVSAvoiddifferential sticking and damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The probe assembly is designed to be movable between a retracted position (for safe conveyance through the borehole) and a deployed position (for sealing and perforation operations). This dynamic configuration allows the tool to adapt to different operational phases, reducing the risk of damage during conveyance while enabling effective formation evaluation when deployed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The probe assembly seals off a region of the borehole wall before perforation occurs. This preliminary sealing action prevents differential pressure from causing sticking or damage during subsequent perforation and fluid injection operations, thereby protecting the tool while enabling reliable formation testing.

Inventive Principle:

Principle #9Preliminary anti-action

2Adaptability or versatility

If existing tools are used for formation evaluation, then some testing capability is provided, but they fail to effectively reach beyond the altered zone around the borehole

Engineering Contradiction:

Improveperforation capabilityVSAvoidperforation depth

Core Design Contradiction:

Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The system separates the sealing function (probe assembly) from the perforation function (perforator), allowing the perforator to project through the sealed region and penetrate deep into the formation. This segmentation enables the tool to effectively reach beyond the altered zone around the borehole while maintaining a sealed testing environment.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The probe assembly acts as an intermediary that creates a sealed environment, allowing the perforator to safely penetrate through casing and cement into the formation without compromising the sealing integrity. This mediator enables deep perforation while maintaining controlled testing conditions.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If a probe assembly is deployed to seal the borehole wall, then formation testing accuracy is improved, but tool complexity increases

Engineering Contradiction:

Improveformation testing accuracyVSAvoidtool complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The probe assembly serves multiple functions: it seals off the borehole wall to create a isolated testing region, provides a mounting structure for the perforator, and enables both formation evaluation and perforation operations. This multi-functionality reduces the need for separate tools, thereby managing complexity while improving measurement precision.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Strength

If the perforator projects through the probe assembly, then effective perforation of consolidated formation, casing and cement is achieved, but the risk of tool damage during conveyance increases

Engineering Contradiction:

Improveperforation effectivenessVSAvoidtool damage risk

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The probe assembly is retracted during conveyance to protect the perforator, and only deployed when the tool reaches the target formation. This dynamic positioning minimizes the exposure of vulnerable components during high-risk conveyance operations while enabling effective perforation when needed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The probe assembly is deployed to seal the borehole wall before the perforator is activated. This preliminary sealing prevents formation fluids and pressures from interfering with the perforation process, thereby protecting the tool while enabling effective penetration through consolidated formation, casing, and cement.

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS8991245B2Apparatus and methods for characterizing a reservoir

Publication Date: 2015.03.31 SCHLUMBERGER TECH CORP

AI summary

An apparatus comprising a downhole tool configured for conveyance within a borehole penetrating a subterranean formation, wherein the downhole tool comprises: a probe assembly configured to seal a region of a wall of the borehole; a perforator configured to penetrate a portion of the sealed region of the borehole wall by projecting through the probe assembly; a fluid chamber comprising a fluid; and a pump configured to inject the fluid from the fluid chamber into the formation through the perforator.