Annular Interval Density Computation for Wellbore Inflow Detection

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Solution Overview

Problem

Current methods lack the capability to compute sequential and non-sequential pressure and temperature interval densities in subterranean wellbores, and fail to utilize these measurements to characterize formations, drilling fluid, and drilling processes effectively.

Innovation Solution

Deploying a tool string with axially spaced pressure sensors in a subterranean borehole to compute annular interval densities, which can indicate inflow or outflow events, and using these measurements to determine the density of inflow constituents and identify lost circulation events.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If along string pressure and temperature measurements are taken, then real-time monitoring capability is improved, but the ability to compute interval densities and characterize formations is insufficient

Engineering Contradiction:

Improvereal-time monitoring capabilityVSAvoidinterval density computation capability

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The patent transforms raw pressure and temperature measurements into derived parameters (interval densities, inflow constituent densities) through computational processing. This parameter transformation enables characterization of subterranean formations, drilling fluid, and drilling process conditions that cannot be obtained from raw measurements alone, thereby resolving the information loss issue while maintaining real-time monitoring capabilities

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If multiple axially spaced pressure sensors are deployed, then detection capability for inflow/outflow events is improved, but device complexity increases

Engineering Contradiction:

Improvedetection capability for inflow/outflow eventsVSAvoidnumber of pressure sensors

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the wellbore into multiple axial intervals, each monitored by dedicated pressure sensors. This segmentation enables localized detection of inflow/outflow events at specific depth intervals, providing precise spatial resolution of formation interactions while distributing the measurement function across multiple simple sensor units rather than requiring a single complex sensor system

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent replaces complex mechanical intervention methods with electronic sensor arrays and computational analysis. Instead of requiring physical sampling or invasive formation testing, the system uses distributed pressure sensors coupled with interval density computations to detect and characterize inflow/outflow events, reducing mechanical complexity while enhancing detection precision

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Loss of information

If interval density computations are performed, then characterization of drilling fluid and formations is improved, but processing time and computational requirements increase

Engineering Contradiction:

Improvecharacterization capabilityVSAvoidprocessing time

Core Design Contradiction:

Loss of informationVSLoss of time

Solution Approach 1:

The patent performs interval density computations continuously as pressure and temperature data become available during drilling operations, rather than waiting for complete data sets. This preliminary processing approach enables real-time characterization of drilling fluid properties and formation conditions, preventing information loss without requiring excessive processing time by computing results incrementally as measurements are taken

Inventive Principle:

Principle #10Preliminary action

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 timely detection of inflow and outflow events, allowing for timely mitigation of potential kicks and identification of lost circulation, thereby improving drilling operation efficiency and safety.

Implementation Method 1

acquiring first and second subsurface annular pressure measurements at corresponding first and second measured depths in the wellbore

Methodology Applied

Scientific EffectPressure measurement:

Implementation Method 2

causing a processor to process the first and second annular pressure measurements to compute an annular interval density between the first and second measured depths in the wellbore

Methodology Applied

Scientific EffectDensity computation from pressure gradient:

Implementation Method 3

changes in the computed interval density with time may be used as an indicator of either an inflow of formation fluid into the wellbore

Methodology Applied

Scientific EffectFluid density detection:

Data Source

PatentUS10190407B2Methods for evaluating inflow and outflow in a subterraean wellbore

Publication Date: 2019.01.29 SCHLUMBERGER TECH CORP

AI summary

A method for evaluating inflow or outflow in a subterranean wellbore includes acquiring first and second axially spaced pressure measurements in the wellbore. The pressure measurements may then be processed to obtain an interval density of drilling fluid between the measurement locations. A tool string including a large number of axially spaced pressure sensors (e.g., four or more or even six or more) electronically coupled with a surface processor via wired drill pipe may be used to obtain a plurality of interval densities corresponding to various wellbore intervals. The interval density may be measured during static conditions or while drilling and may be further processed to compute a density of an inflow constituent in the annulus. Changes in the computed interval density with time may be used as an indicator of either an inflow event or an outflow event.