Angular Polymeric Lost Circulation Objects for Fracture Bridging
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Solution Overview
Problem
Drilling fluids face significant challenges in preventing lost circulation due to the loss of fluid into fractured or permeable formations, where existing solutions fail to effectively balance pore pressures and fracture pressures, leading to fluid leakage and formation fluid ingress.
Innovation Solution
Development of polymeric solid objects with specific size and shape characteristics, such as edges, corners, and projections, which are designed to be rigid and resilient, allowing them to lodge in fractures and form bridges or plugs to prevent fluid loss, made through a curing process in molds and potentially enhanced with additives for neutral buoyancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lost circulation materials (flakes, granules) are used to plug fractures, then fluid loss is reduced, but the materials lack defined shape characteristics that would improve their ability to lodge effectively in fractures
Solution Approach 1:
The patent applies parameter changes by specifying precise geometric parameters for the lost circulation materials, including particle size (0.5-5mm), shape factors (aspect ratio 0.5-2.0), and surface area (0.01-10mm²). This transforms the conventional undefined particle morphology into controlled geometric parameters that optimize fracture plugging effectiveness while maintaining flowability in the drilling fluid.
2Reliability
If drilling fluid pressure is increased to prevent formation fluid ingress, then pore pressure control is improved, but fracture pressure is exceeded causing drilling fluid loss
Solution Approach 1:
The patent applies preliminary action by introducing lost circulation materials into the drilling fluid before encountering the fracture. These materials are carried by the drilling fluid to the fracture zone in advance, where they proactively plug the fracture pathways before significant fluid loss occurs, preventing the need to exceed fracture pressure to maintain well control.
3Reliability
If larger particles are used to plug fractures, then plugging effectiveness is improved, but particle transport to fracture becomes difficult
Solution Approach 1:
The patent resolves this contradiction through optimized parameter selection: particles with sizes of 0.5-5mm and controlled aspect ratios (0.5-2.0) achieve sufficient plugging effectiveness while maintaining adequate transportability. The specific surface area parameters (0.01-10mm²) ensure particles are large enough to bridge fractures but small enough to remain suspended and transported by the drilling fluid flow.
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
The polymeric objects effectively mitigate fluid loss by engaging with fracture surfaces, reducing permeability and preventing further leakage, while maintaining structural integrity under drilling conditions.
Implementation Method 1
filling the mould with a curable liquid organic pre-polymer composition, curing the composition to a solid state in the mould
Data Source
AI summary
Solid polymer objects have size at least 0.5 mm in each of three orthogonal dimensions and shape such that each object has one or more edges, points or corners and/or has a plurality of projections which extend out from a core portion. Such objects may be included in a drilling fluid as a lost circulation additive intended to bridge fractures and mitigate fluid loss. Their angular shape features make it harder for them to slide over fracture faces or each other and helps them to bridge a fracture. A method of making these objects provides a travelling endless belt made of elastomer and defining mould cavities. The mould cavities are filled with a polyerisable liquid composition, which is cured in the mould as the belt advances, and the cured objects are ejected from a mould as the belt bends around a roller.