Wellbore Strengthening Fluids for Drilling Stability
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Solution Overview
Problem
In drilling operations, lost circulation due to fluid leakage into permeable formations and fractures leads to non-productive drilling time and increased costs, particularly in formations with narrow mud weight windows where overbalance pressure can induce fractures, causing fluid loss and requiring remedial treatments.
Innovation Solution
The design of wellbore strengthening additives and fluids based on the assessment of wellbore strengthening materials, involving the use of tools with sensors to measure plug properties such as normal plug pressure and displacement, allowing for the derivation of values like sustained increased hoop stress and compressive strength, which informs the development of more effective wellbore strengthening materials and fluids to expand the mud weight window and prevent fluid loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If overbalance pressure is increased to prevent formation fluids from entering the wellbore, then wellbore stability is improved, but fracture pressure is exceeded causing induced fractures and lost circulation
Solution Approach 1:
The patent applies preliminary action by introducing wellbore strengthening materials into the drilling fluid before encountering problematic zones. These materials are positioned in advance to create a strengthened zone around the wellbore, allowing the wellbore to withstand higher overbalance pressures without inducing fractures. The strengthening effect is established before the harmful pressure effects occur.
Solution Approach 2:
The patent uses composite materials by combining wellbore strengthening materials (such as fibers, particles, or polymers) with the drilling fluid to create a composite drilling fluid system. This composite fluid provides both the necessary overbalance pressure for wellbore stability and enhanced fracture resistance through the reinforcing properties of the strengthening materials.
2Loss of substance
If wellbore strengthening materials are used to expand the mud weight window, then lost circulation is reduced, but device complexity increases due to additional tools and sensors required for assessment
Solution Approach 1:
The patent applies copying by using a scaled-down model or simulation system to assess the properties of plugs formed by wellbore strengthening materials. Instead of requiring complex downhole testing equipment, the invention uses a laboratory-scale apparatus that replicates downhole conditions, allowing assessment of plug strength, compressibility, and other critical properties using simpler, more accessible equipment.
3Strength
If plug strength is increased to withstand higher pressures, then wellbore strengthening effect is improved, but manufacturing precision requirements increase for controlling plug properties
Solution Approach 1:
The patent applies parameter changes by systematically varying key parameters of the wellbore strengthening materials (such as concentration, particle size distribution, fiber aspect ratio, and chemical composition) to optimize plug strength. By understanding the relationship between material parameters and plug performance, the invention enables control of plug properties through adjustable formulation parameters rather than requiring extreme manufacturing precision.
Data Source
AI summary
Generally, assessing the properties of a plug comprising wellbore strengthening materials may enable the design of more efficient wellbore strengthening additives and fluids because the properties of the plug may translate to the near wellbore strengthening effect of the wellbore strengthening materials of the plug. Assessing such properties may involve applying a differential pressure to a plug formed in a passageway of a tool comprising at least one sensor proximal to the passageway plug, and then measuring at least one attribute selected from the group consisting of a normal plug pressure, a normal plug displacement, and any combination thereof with the at least one sensor.