Block Polymer Fluid Loss Control in Oil Extraction
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Solution Overview
Problem
Existing fluid loss control agents in oil extraction are not fully effective, especially in the presence of additives like dispersing agents or set retarders, and fail to prevent fluid loss and gas migration in subterranean formations, leading to well instability and cement weakening.
Innovation Solution
The use of specific block polymers with a short block irreversibly adsorbed on particles and a long, soluble block to form a polymer layer that anchors to particles, creating a 'plug' to prevent fluid loss, even in the presence of harmful additives, by combining with particles in the subterranean formation or during cementing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fluid loss control agents are used, then some fluid loss control is achieved, but they become ineffective in the presence of dispersing agents or set retarders
Solution Approach 1:
The invention uses a block copolymer composed of two distinct blocks: a first block that is insoluble in the continuous phase and a second block that is soluble. This composite structure allows the first block to anchor to particles while the second block extends into the fluid phase to control fluid loss, achieving effectiveness even in the presence of other additives like dispersing agents or set retarders.
Solution Approach 2:
The block copolymer exhibits different properties in different parts of its structure. The first block (insoluble) provides localized anchoring to particles, while the second block (soluble) provides localized fluid loss control in the continuous phase. This local differentiation of properties allows the single polymer to perform multiple functions simultaneously without interference from other additives.
2Productivity
If fluid is injected under pressure into subterranean formation, then oil extraction is enabled, but fluid loss occurs into the rock
Solution Approach 1:
The block copolymer acts as an intermediary substance that forms a barrier layer around particles in the subterranean formation. The insoluble first block anchors to the particles while the soluble second block extends into the injected fluid, creating a protective interface that prevents direct contact between the fluid and rock, thereby controlling fluid loss while maintaining productivity.
3Reliability
If insoluble compounds are present in injected fluid, then fluid loss control is enhanced, but viscosity increases and mobility decreases
Solution Approach 1:
The invention changes the physical and chemical parameters of the fluid by introducing block copolymers with specific properties. The insoluble first block provides fluid loss control by anchoring to particles, while the soluble second block maintains fluid mobility by extending into the continuous phase. This parameter optimization allows simultaneous achievement of fluid loss control and acceptable fluid mobility.
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 block polymer system effectively controls fluid loss and gas migration, maintaining well integrity and cement stability, even in challenging formulations like oil cement grouts, drilling fluids, and fracturing fluids.
Implementation Method 1
a first block (A), also known as 'short block' hereinafter, with a weight-average molecular weight typically of less than 30 000 g/mol, which is adsorbed, preferably irreversibly, on at least a portion of the particles (p)
Data Source
AI summary
The present invention relates to the use of a block polymer as fluid loss control agent in a fluid injected under pressure into an oil-bearing rock, where:the fluid comprises solid particles and/or is brought into contact with solid particles within the oil-bearing rock subsequent to its injection,the polymer comprises:a first block which is adsorbed on at least a portion of the particles; anda second block with a composition distinct from that of the first and with a weight-average molecular weight of greater than 10 000 g/mol, for example of greater than 100 000 g/mol, and which is soluble in the fluid.