Continuous Well Logging Using Rock Cuttings for Mechanical Profiles
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Solution Overview
Problem
Conventional logging methods fail to provide a continuous and complete profile of the mechanical properties of a well section due to poor core recovery and alignment, leading to difficulties in obtaining accurate rock mechanical properties from rock cuttings.
Innovation Solution
A continuous logging method involving micro-indentation and triaxial compression experiments to determine correlations between static and dynamic parameters of rock cuttings and full-diameter core samples, enabling a formation mechanical property profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If full-diameter cores are obtained by well drilling and coring, then rock mechanical properties can be obtained through laboratory experiments, but poor columnar cores, serious core loss, low core recovery rate and low core alignment rate occur, resulting in difficulties in continuous coring
Solution Approach 1:
The patent uses rock cuttings as a substitute (copy) for full-diameter cores. Instead of relying on difficult-to-obtain core samples, the method analyzes rock cuttings which are easily collected during drilling, establishing correlation models between cuttings properties and core mechanical properties to achieve the same measurement objective
Solution Approach 2:
The patent introduces rock cuttings as an intermediary between the drilling process and mechanical property analysis. The cuttings serve as a mediator that can be easily obtained and analyzed, with correlation models acting as the intermediary mechanism to translate cuttings data into meaningful mechanical properties
2Productivity
If rock cuttings logging technology is used, then drilling fragment samples can be obtained, but it is difficult to obtain the rock mechanical properties of a target formation segment
Solution Approach 1:
The patent transforms the measurement approach by changing from direct mechanical testing of cores to indirect measurement through correlation models. Multiple parameters including mineral composition, microstructure characteristics, and physical properties are measured on cuttings, and these parameters are used in correlation models to derive mechanical properties
Solution Approach 2:
The patent replaces the mechanical testing system (triaxial compression experiments on cores) with a combination of chemical/mineralogical analysis and computational correlation models. Instead of physically testing core samples, the system uses mineral composition analysis and statistical correlations to determine mechanical properties
3Quantity of substance
If conventional logging methods are used, then logging data can be obtained, but a continuous and complete profile of the mechanical property of the whole well section cannot be drawn
Solution Approach 1:
The patent enables continuous logging by processing rock cuttings at regular intervals throughout the drilling operation. The method maintains continuous measurement capability by analyzing cuttings from each drilling segment, ensuring no gaps in the mechanical property profile along the well section
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 a continuous and complete profile of the mechanical properties of a well section, facilitating accurate analysis and identification of sweet and non-sweet spot regions for optimized fracturing and oil recovery.
Implementation Method 1
performing a micro-indentation experiment on the target rock cuttings to obtain a static parameter thereof
Implementation Method 2
performing a triaxial compression experiment on the full-diameter core samples to obtain a dynamic parameter and a static parameter thereof
Data Source
AI summary
A continuous logging method and device is provide, where the method includes obtaining drilling fragment samples and full-diameter core samples, and screening out target rock cuttings from the drilling fragment samples; performing a micro-indentation experiment on the target rock cuttings to obtain a static parameter thereof; performing a triaxial compression experiment on the full-diameter core samples to obtain a dynamic parameter and a static parameter thereof; determining a first correspondence between the static parameter of the target rock cuttings and the dynamic parameter of the full-diameter core samples; determining a second correspondence between logging data and the static parameter of the target rock cuttings based on the first correspondence; and drawing a formation mechanical property profile based on the second correspondence. The method solves the problem of conventional methods which cannot draw a continuous and complete profile of the mechanical property of the whole well section.