Reverse Drill Stem Testing Fluid Pill Injection

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Solution Overview

Problem

Conventional drill stem testing (DST) methods face challenges in accurately evaluating subsurface formations due to environmental and safety concerns, as well as the risk of damaging the formation during testing, which can lead to inaccurate results and increased operational costs.

Innovation Solution

A customized injection fluid with particulates is used, which is designed to match the weight of the drilling mud, allowing for precise injection and filtration, enabling a reverse drill stem testing method that minimizes formation alteration and uses a fluid pill to simulate hydrocarbon extraction potential without causing wellbore collapse, while also incorporating a tracer for fluid differentiation and additives for stability and cleanliness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional drill stem testing methods are used to evaluate subsurface formations, then formation evaluation data can be obtained, but environmental and safety concerns arise and the formation may be damaged leading to inaccurate results

Engineering Contradiction:

Improveformation evaluation accuracyVSAvoidformation damage and environmental risk

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the conventional DST approach by injecting fluid into the formation rather than withdrawing formation fluid into the wellbore. This reverse approach allows evaluation of formation properties while avoiding the formation damage and safety issues associated with conventional fluid withdrawal methods

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent uses a specially formulated injection fluid as an intermediary substance that matches the density of drilling mud to prevent wellbore collapse while enabling formation evaluation. This intermediary fluid serves as a safe medium that eliminates environmental concerns and formation damage risks

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If fluid is injected into the formation for testing, then formation properties can be evaluated, but the injection fluid may cause wellbore collapse or formation damage

Engineering Contradiction:

Improveformation property evaluationVSAvoidwellbore stability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent changes the density parameter of the injection fluid to match the drilling mud density, preventing wellbore collapse. The injection fluid is formulated with specific density, viscosity, and composition parameters that ensure wellbore stability while enabling accurate formation evaluation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies different fluid properties at different locations: the injection fluid has matched density in the wellbore area to prevent collapse, while maintaining different chemical composition and viscosity characteristics in the formation zone to enable accurate permeability and pressure evaluation

Inventive Principle:

Principle #3Local quality

3Reliability

If drilling mud is used directly for injection testing, then wellbore stability is maintained, but accurate formation evaluation is compromised due to mud composition interference

Engineering Contradiction:

Improvewellbore stabilityVSAvoidformation evaluation accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent segments the fluid system into two distinct components: drilling mud for wellbore stability and a separate injection fluid for formation evaluation. The injection fluid is introduced as a distinct fluid pill within the mud stream, allowing it to reach the formation without the interfering composition of drilling mud while the mud maintains wellbore stability

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 approach allows for more accurate and safe formation evaluation by stabilizing the wellbore, preventing collapse, and providing clear, controlled injection tests that reduce environmental impact and operational risks, while enhancing the accuracy of hydrocarbon extraction potential assessments.

Implementation Method 1

The packers can be deployed to seal the zone to isolate the test zone from the wellbore

Methodology Applied

Scientific EffectSealing:

Implementation Method 2

a filter to remove a particulate from a fluid pill prior to injection of the injection fluid into the zone

Methodology Applied

Scientific EffectFiltration: Filter (physical)

Data Source

PatentUS11624279B2Reverse drill stem testing

Publication Date: 2023.04.11 HALLIBURTON ENERGY SERVICES INC

AI summary

A method comprises flowing a mud into a wellbore, wherein the mud has a mud composition and has a weight in a defined range. The method includes introducing a fluid pill into the mud flowing into the wellbore, wherein the fluid pill has an injection fluid with an injection composition that is different from the mud composition. A particulate has been added to the injection fluid to increase the weight of the fluid pill. After flowing the mud into the wellbore such that the fluid pill is positioned in a zone of the wellbore: filtering out the particulate from the injection fluid; injecting, after the filtering, the injection fluid into the zone; measuring a downhole parameter that changes in response to injecting the injection fluid into the zone; and determining a property of the formation of the zone based on the measured downhole parameter.