In-situ Polymerized Gel Plug for Drilling Fluid Loss
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Solution Overview
Problem
Current methods for mitigating lost circulation while drilling a wellbore, such as installing casing strings, are time-consuming, costly, and limited by frictional forces, necessitating the need for improved solutions to prevent mud loss into porous or fractured formations.
Innovation Solution
The method involves circulating drilling mud and detecting lost circulation events, followed by introducing a monomer solution and catalyst to polymerize a viscous plug within the wellbore, which is then flowed into the zone of loss to occlude fluid flow, thereby preventing further mud loss without the need for casing installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If casing strings are installed to mitigate lost circulation, then fluid flow into the formation is prevented, but the drilling process becomes time-consuming and costly
Solution Approach 1:
The invention changes the physical state and properties of the drilling fluid by polymerizing a monomer solution in-situ to create a gel plug. This transforms the fluid parameters (viscosity, density) to block fluid loss, eliminating the need for casing installation and resolving the time-cost contradiction while maintaining reliability.
Solution Approach 2:
The gel plug formed from polymerized monomer acts as an intermediary material between the drilling fluid and the formation. This gel plug prevents direct fluid communication with the formation, achieving the same function as casing but without the installation time and cost penalties.
2Reliability
If casing strings are installed to mitigate lost circulation, then fluid flow into the formation is prevented, but the overall wellbore depth is limited by frictional forces
Solution Approach 1:
By changing the physical parameters of the drilling fluid through in-situ polymerization, the gel plug provides effective fluid loss prevention without the mechanical constraints of casing strings. This allows the wellbore to extend to greater depths limited only by drilling capabilities rather than casing friction.
Solution Approach 2:
The invention extracts the fluid loss prevention function from the mechanical casing structure and implements it through a chemical gel plug. This removes the limiting factor of casing friction and enables greater wellbore depth while maintaining reliability.
3Reliability
If smaller casing strings are installed within existing casing strings to respond to subsequent lost circulation events, then fluid loss is prevented, but the process can only be repeated a limited number of times
Solution Approach 1:
The gel plug approach changes the method of fluid loss prevention from mechanical nesting to chemical transformation. This simplifies the device complexity by eliminating multiple casing strings and allows repeated treatment of lost circulation events without adding structural complexity.
Solution Approach 2:
The gel plug system provides self-service fluid loss prevention that can be deployed repeatedly without requiring complex nested casing structures. Each gel plug treatment is independent and can address subsequent lost circulation events without increasing overall system complexity.
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
This approach allows for continued drilling without casing installation, increasing wellbore length while effectively preventing mud loss into porous or fractured formations, thus enhancing drilling efficiency and reducing costs.
Implementation Method 1
combining the monomer solution and the catalyst to polymerize a monomer from the monomer solution, within the wellbore, and forming a viscous plug within the wellbore
Implementation Method 2
flowing at least a portion of the viscous plug within the wellbore and into a zone of lost circulation that extends within a subsurface region
Data Source
AI summary
Methods of mitigating lost circulation while drilling a wellbore. The methods include circulating a drilling mud to a downhole end of the wellbore via a drill string and, during the circulating, drilling the wellbore with a drill bit of the drill string. The methods also include detecting lost circulation within the wellbore while drilling the wellbore and include providing a monomer solution to the wellbore. The methods further include providing a catalyst to the wellbore responsive to detecting the lost circulation event and combining the monomer solution and the catalyst to polymerize a monomer from the monomer solution, within the wellbore, and forming a viscous plug within the wellbore. Subsequent to the combining, the methods include flowing at least a portion of the viscous plug within the wellbore and into a zone of lost circulation that extends within a subsurface region. The methods further include at least partially occluding fluid flow from the wellbore and into the zone of lost circulation with the viscous plug.