Lost-circulation composition, lost-circulation material and use thereof
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Solution Overview
Problem
Existing lost-circulation compositions fail to effectively plug water-bearing formations due to dilution, low retention, and poor high-temperature resistance, leading to inadequate plugging in flowing water-bearing formations.
Innovation Solution
A cross-linkable polymer-based composition that forms a gel before or during injection, which is cured to create a lost-circulation material with high mass retention and shear strength, suitable for temperatures up to 180°C, using ingredients like polyacrylamide, cross-linking agents, and enhancers to enhance adhesion and resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lost circulation slurry is used in water-bearing formations, then the slurry can be injected into the formation, but the slurry is easily diluted and displaced by water flow, resulting in reduced viscosity and concentration, and the material flows away instead of being retained
Solution Approach 1:
The patent changes the physical and chemical parameters of the lost circulation material by using cross-linkable polymers that transform from soluble state to gel state through cross-linking reactions. This parameter change enables the material to resist water dilution and maintain retention capability in water-bearing formations, directly resolving the contradiction between retention and water dilution.
Solution Approach 2:
The patent employs composite material systems combining cross-linkable polymers, cross-linking agents, and consolidating materials. These composite materials exhibit enhanced properties including water resistance, adhesion, and structural integrity, allowing the slurry to withstand water flow displacement and achieve reliable retention in flowing water-bearing formations.
2Reliability
If conventional lost circulation slurry is used in flowing water-bearing formations, then the slurry can be injected, but the slurry is quickly taken away by formation water, preventing plugging wall formation and causing plugging operation failure
Solution Approach 1:
The patent applies preliminary action by enabling the lost circulation material to undergo cross-linking and consolidation before being fully displaced by water flow. The cross-linkable polymer forms a gel structure in advance, and the consolidating material prepares for curing, creating a pre-strengthened plugging wall that resists water flow displacement and ensures plugging effectiveness in flowing water-bearing formations.
Solution Approach 2:
The patent utilizes the curvature and continuity of the gel network structure formed by cross-linked polymers. This continuous three-dimensional network provides structural integrity and coherence to the plugging wall, enabling it to withstand water flow forces and maintain plugging effectiveness, directly addressing the failure of conventional linear or discrete material systems.
3Strength
If conventional lost circulation slurry is used in high-temperature formations, then the slurry can be injected, but the slurry cannot be properly coagulated and cured after dilution, or the setting strength is greatly reduced, causing plugging operation failure
Solution Approach 1:
The patent employs parameter changes by selecting cross-linking and consolidation reactions that are optimized for high-temperature conditions. The cross-linkable polymers and consolidating materials are chosen to undergo effective cross-linking and curing reactions within the temperature range of 50-180°C, maintaining setting strength despite thermal conditions and water dilution, thus resolving the contradiction between strength development and high-temperature resistance.
4Strength
If pretreating agent is used to form substance with high adhesion and wall-hanging property, then the substance can be formed in water-bearing layer, but the substance is easily washed away by water in flowing water-bearing formation
Solution Approach 1:
The patent uses composite materials combining cross-linked polymer gels with consolidating materials that provide both adhesion to formation surfaces and resistance to water washing. The cross-linked network structure provides cohesive strength while the consolidated material provides adhesive bonding and water resistance, enabling the plugging material to maintain both high adhesion and resistance to water flow in flowing water-bearing formations.
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 90% mass retention and 0.1-0.14 MPa lap anti-shear strength, providing effective plugging and resistance to water dilution and high temperatures, suitable for water-bearing formations.
Implementation Method 1
the lost-circulation composition can be cross-linked to form a gel before or during being injected into the formation
Implementation Method 2
the gel can be cured at the lost-circulation formation to form a lost-circulation material
Data Source
AI summary
A lost-circulation composition for oil drilling operations can be cross-linked to form a gel before or during being injected into the formation, and the gel can be cured at the lost-circulation formation to form a lost-circulation material. The mass retention rate of the gel when scouring at 50-180° C. for 30 min at a water flow rate of 10 m/min is 90% or more. The lap anti-shear strength of the lost-circulation material is 0.1-0.14 MPa. The lost-circulation composition of the present invention is suitable for a water-bearing formation having a temperature of not higher than 180° C., especially a flowing water-bearing formation. The lost-circulation composition can be cross-linked to form a gel, and after being injected into the water-containing formation, the gel can realize strong retention around a wellbore, and can be cured under formation conditions to form a lost-circulation material, which finally blocks the lost-circulation formation.