Lost Circulation Material Evaluation Under Simulated Downhole Conditions
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Solution Overview
Problem
Current methods for evaluating lost circulation materials in drilling fluids are limited by their inability to accurately simulate downhole conditions, leading to inadequate assessment of material properties under high pressure and temperature, which can result in inefficient wellbore strengthening and increased risk of fluid loss.
Innovation Solution
A system and method that uses an apparatus with a cylindrical wall, piston, and screen to simulate downhole conditions by adjusting volume and applying pressure and temperature, allowing for continuous measurement of stress-strain relationships of lost circulation materials, including a heater and insulation to mimic downhole environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If lost circulation materials are used to increase particle size to plug thief zones, then the ability to seal larger openings is improved, but the pumpability of drilling fluid is worsened due to size limitations
Solution Approach 1:
The lost circulation material is segmented into multiple size fractions, with a majority of particles in a smaller size range (e.g., 2-8 mesh) for pumpability and a minority in larger sizes (e.g., 4-20 mesh) for sealing capability. This segmentation allows the material to be pumped effectively while still providing adequate plug zones for larger openings.
Solution Approach 2:
Different regions of the lost circulation material population have different size qualities optimized for different functions. The smaller particles are distributed throughout the drilling fluid for pumpability and baseline sealing, while larger particles are concentrated in specific fractions to target and plug larger thief zones and cracks.
2Measurement precision
If current evaluation methods are used, then the assessment process is simple, but the accuracy of material property assessment under downhole conditions is insufficient
Solution Approach 1:
An intermediary evaluation system is introduced that includes a pressure vessel, heating apparatus, and compression device. This intermediary system simulates downhole conditions (temperature, pressure, confining stress) in a laboratory setting, allowing accurate assessment of lost circulation material properties without requiring actual downhole testing.
Solution Approach 2:
The evaluation system changes key parameters (temperature, pressure, confining stress) to match downhole conditions. The heating apparatus raises temperature to downhole levels, the pressure vessel applies hydrostatic pressure, and the compression device applies confining stress, thereby transforming laboratory conditions into realistic downhole simulation conditions for accurate material assessment.
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 the accurate evaluation of lost circulation material properties under simulated downhole conditions, providing continuous data on pressure and compaction/expansion, thereby improving wellbore strengthening and reducing fluid loss during drilling.
Implementation Method 1
The lost circulation material residing within the cavity is heated to a specified test temperature mimicking a downhole temperature
Implementation Method 2
applying force on the piston to pressurize the test fluid residing within the cavity to a specified test pressure mimicking a downhole pressure
Data Source
AI summary
A lost circulation material is placed in a cavity. The cavity is defined by an inner bore of a cylindrical wall, intermediate of a piston and a screen. A distance between the piston and the screen is defined as the height of the cavity, which is adjustable. The piston is slid longitudinally, such that the piston comes in contact with the lost circulation material. The lost circulation material is heated to a specified test temperature mimicking a downhole temperature. A compression test is performed on the lost circulation material. The compression test includes flowing a test fluid into the cavity and applying force on the piston to pressurize the test fluid to a specified test pressure mimicking a downhole pressure. The force on the piston is released. The pressure of the test fluid and the height of the cavity are measured throughout the compression test.