Drilling Fluid Additive Composition for High-Pressure Plugging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current plugging methods for lost circulation in well drilling, such as bridge plugging and cement plugging, face challenges in controlling setting times and achieving high-strength seals, leading to uncertainties and potential leaks due to mismatched particle sizes and high differential pressures.
Innovation Solution
A drilling fluid additive composition comprising a weak-crosslinked copolymer, modified silicon dioxide nanoparticles, a dimer acid-organic amine copolymer, carboxymethyl chitosan with a dopamine-derived group, and a binary polyamino acid inhibitor, which synergistically provides bridging, plugging, anti-collapse, and shale inhibition effects, ensuring effective sealing and pressure resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bridge plugging is used to seal fractures and pore channels, then the leak formation can be sealed under bridging and plugging effects, but the success ratio is compromised because the particle size distribution of the bridging agent cannot be matched to the unknown widths of fractures and sizes of pores in the leak formation
Solution Approach 1:
The bridging agent is divided into multiple particle size segments (0.1-1mm, 1-2mm, 2-4mm, 4-8mm, 8-16mm) to cover a wide range of fracture and pore channel dimensions. This segmentation allows the plugging composition to adapt to unknown leak formation characteristics without requiring prior knowledge of fracture sizes.
Solution Approach 2:
The plugging composition is designed with multi-functional components that work together: nano-plugging agents for fine pores, micro-plugging agents for larger fractures, rheological modifiers for flow control, and shale inhibitors for wall stabilization. This universal composition can handle various leak scenarios without requiring formulation changes.
2Reliability
If cement plugging is used to plug fractures and solution cavities, then the leak formation can be sealed, but the initial setting time and final setting time are difficult to control, leading to high construction risk and potential downhole accidents
Solution Approach 1:
The rheological modifier (dimer acid-organic amine copolymer) enables precise control of the plugging slurry's flow parameters and setting characteristics. By adjusting the concentration and molecular weight of the copolymer, the setting time can be controlled within a wide range without affecting the final plugging effectiveness, eliminating the timing control problems associated with cement plugging.
3Strength
If conventional plugging materials are used, then plugging can be attempted, but the plugged formation doesn't have high strength and may leak again owing to the high differential pressure in the well drilling process
Solution Approach 1:
The plugging composition combines multiple materials with complementary properties: nano-plugging agents (modified silicon dioxide) for fine pore sealing, micro-plugging agents (weak-crosslinked copolymers) for fracture bridging, rheological modifiers for structural integrity, and shale inhibitors for wall stabilization. This composite approach creates a multi-layered plugging structure with high strength and excellent resistance to differential pressure that prevents subsequent leaks.
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 composition achieves successful one-off plugging with high pressure bearing capability, improves mud cake smoothness and density, and maintains effective rheological properties, reducing the risk of leaks and operational costs by matching fracture sizes and stabilizing well walls.
Implementation Method 1
the bridging agent is a weak-crosslinked copolymer that contains structural units represented by formula (1), structural units represented by formula (2), and structural units represented by formula (3), and content of cross-linker structures in the weak-crosslinked copolymer is 0.1-1 wt. %
Implementation Method 2
The nano-plugging agent is a modified silicon dioxide nano-particle, modifying group on the modified silicon dioxide nano-particle includes an acrylic copolymer chain
Implementation Method 3
the rheological modifier is a dimer acid-organic amine copolymer comprising structural units from dimer acid, structural units from alkylamine and structural units from arylamine
Implementation Method 4
the bionic wall bracing agent is carboxymethyl chitosan with a dopamine-derived group represented by the following formula (I-1) grafted on its main chain
Implementation Method 5
the bionic shale inhibitor is composed of structural units represented by the following formula (III-1) and structural units represented by the following formula (IV-1)
Data Source
AI summary
The present invention relates to the well drilling field in petroleum industry, in particular to a drilling fluid additive composition and a water-based drilling fluid suitable for high pressure plugging while drilling. The composition contains a bridging agent, a nano-plugging agent, a rheological modifier, a bionic wall bracing agent, and a bionic shale inhibitor, wherein, the bridging agent is a weak-crosslinked copolymer, in which the content of cross-linker structures is 0.1-1 wt. %; the nano-plugging agent is modified nanometer silicon dioxide particles; the rheological modifier is a dimer acid-organic amine copolymer; and the bionic wall bracing agent is carboxymethyl chitosan with a dopamine-derived base group grafted on its main chain. With a synergistic effect among the bridging agent, the nano-plugging agent, the rheological modifier, the bionic wall bracing agent, and the bionic shale inhibitor in the composition provided in the present invention, the water-based drilling fluid containing the composition as additive can attains an excellent plugging effect in a drilling process.