Log Processing in Highly Deviated Wellbores Using Segmentation

Solution Overview

Problem

Current log processing methods are inadequate for highly deviated wellbores, particularly those exceeding 90 degrees of deviation, as they fail to account for changing dimensional effects and formation orientations, leading to inaccurate determination of true formation properties.

Innovation Solution

A method involving the segmentation of wellbores into constant dimensional effect segments and constant property intervals, using 3D measurement volumes and true stratigraphic thickness, allows for the processing of logging data to accurately determine formation properties by applying appropriate processing models based on specific environmental conditions and formation characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional log processing methods operating in TVD or MD are used, then processing is simple and straightforward, but accuracy deteriorates in highly deviated wellbores exceeding 90 degrees

Engineering Contradiction:

Improveaccuracy of formation property determinationVSAvoidcomplexity of processing method

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The wellbore is divided into multiple constant dimensional effect segments (CDES), each with uniform dimensional effects. This segmentation allows the complex highly deviated wellbore to be processed using simplified models for each segment, improving accuracy without requiring a single overly complex model for the entire wellbore.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different processing models are applied to different segments based on their specific dimensional effect characteristics. Each CDES receives processing tailored to its local conditions (deviation angle, formation orientation), rather than applying a uniform method throughout, thereby improving local accuracy while managing overall complexity.

Inventive Principle:

Principle #3Local quality

2Measurement precision

If a single processing model is used for the entire wellbore, then processing is efficient and quick, but accuracy deteriorates due to ignoring changing dimensional effects and formation orientations

Engineering Contradiction:

Improveaccuracy of formation property determinationVSAvoidprocessing efficiency

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The wellbore is divided into multiple constant dimensional effect segments (CDES), each with uniform dimensional effects. This segmentation allows the complex highly deviated wellbore to be processed using simplified models for each segment, improving accuracy without requiring a single overly complex model for the entire wellbore.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The processing approach changes parameters from continuous variation to discrete segment-based constant values. By defining CDES where dimensional effects are constant, the method simplifies calculations within each segment while capturing overall variations through the sequence of segments, balancing accuracy and efficiency.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If log processing accounts for varying dimensional effects and formation orientations in highly deviated wellbores, then measurement precision improves, but device complexity increases

Engineering Contradiction:

Improveaccuracy of formation property determinationVSAvoidcomplexity of processing system

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The wellbore is divided into multiple constant dimensional effect segments (CDES), each with uniform dimensional effects. This segmentation allows the complex highly deviated wellbore to be processed using simplified models for each segment, improving accuracy without requiring a single overly complex model for the entire wellbore.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The method transitions from processing in one-dimensional TVD or MD to a multi-dimensional approach that incorporates wellbore deviation angle, formation orientation, and segment position. This dimensional expansion allows accurate representation of complex 3D wellbore geometries while using simplified 1D models within each segment.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS8473212B2Log processing in highly deviated wellbores

Publication Date: 2013.06.25 SCHLUMBERGER TECH CORP

AI summary

A method for processing well logging data includes method dividing the well logging data into a number of constant dimensional effect segments, where each constant dimensional effect segment defines an interval having a similar dimensional effect on the log response. The well logging data is taken from a highly deviated well. The method further includes dividing the constant dimensional effect segments into a number of constant property intervals, each constant dimensional effect segment including at least one corresponding constant property interval, and each constant property interval defining a wellbore distance over which a formation property is substantially constant that results in a log response having a low variance. The method further includes providing the constant property intervals to an output device. The method further includes determining constant property intervals in 3D volume space projected them into true stratigraphic thickness, and providing the resulting log-squared data to the output device.