Low-Density Sealant Composition for Subterranean Fracture Prevention

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Solution Overview

Problem

In subterranean formation operations, existing conformance treatments face challenges in reducing the influx of water and gas into oil wells due to high-density conformance fluids, which can lead to unplanned fractures and loss of fluids, and the addition of gas to reduce density often results in unmanageable viscosities and equipment accessibility issues.

Innovation Solution

Development of low-density sealant compositions comprising an aqueous base fluid, a crosslinkable polymer composition, and a density segregation prevention agent, with the inclusion of particulate density reducing agents to achieve reduced densities suitable for conformance control, allowing for effective sealing and reduced fluid loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high-density conformance fluids are used for conformance control treatments, then the sealant can effectively block water and gas flow, but it causes unplanned fractures and loss of fluids due to exceeding the fracture gradient

Engineering Contradiction:

Improvesealing effectivenessVSAvoidunplanned fractures and fluid loss

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies the anti-weight principle by using low-density particulate materials (such as expanded perlite, vermiculite, or hollow glass spheres) to counterbalance the high density of the conformance control fluid. These particulates reduce the overall fluid density to below the fracture gradient of the formation, preventing unplanned fractures and fluid loss while maintaining the fluid's sealing effectiveness against water and gas influx.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The patent employs composite materials by combining conformance control fluids with low-density particulate matter to create a composite conformance treatment fluid. This composite formulation maintains the fluid's ability to seal against water and gas while the integrated low-density particulates reduce the overall density, allowing the fluid to be pumped into depleted zones without exceeding the fracture gradient.

Inventive Principle:

Principle #40Composite materials

2Weight of stationary object

If gas is added to conformance fluids to reduce density, then the fluid density decreases, but the viscosity becomes unmanageable and equipment accessibility is compromised

Engineering Contradiction:

Improvefluid densityVSAvoidviscosity management and equipment accessibility

Core Design Contradiction:

Weight of stationary objectVSEase of operation

Solution Approach 1:

The patent uses solid low-density particulate materials that can be easily added to the conformance fluid and provide permanent density reduction without the operational complications of gas. These particulates remain suspended in the fluid, providing continuous density reduction while maintaining manageable viscosity and pumpability, eliminating the need for complex gas injection equipment.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent avoids using gas (pneumatic approach) and instead employs a hydraulic approach by using liquid-based conformance control fluids combined with low-density solid particulates. This hydraulic system maintains fluid density reduction while ensuring the mixture remains pumpable and manageable through standard wellbore equipment, avoiding the viscosity and accessibility issues associated with gas-filled foams.

Inventive Principle:

Principle #29Pneumatics and hydraulics

3Reliability

If conventional high-density sealants are used, then effective sealing against water and gas is achieved, but significant fluid loss occurs into fractures and high-permeability zones

Engineering Contradiction:

Improvesealant performanceVSAvoidfluid loss

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent applies anti-weight by incorporating low-density particulate materials that reduce the overall sealant density to below the fracture gradient of the formation. This counterbalances the heavy weight of conventional high-density sealants, preventing the sealant from exceeding the fracture gradient and losing fluid into unplanned fractures and high-permeability zones, while maintaining effective sealing performance.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The patent creates a composite sealant formulation by combining conventional sealing agents with low-density particulate matter. This composite structure maintains the sealing effectiveness of the original high-density materials while the integrated low-density particulates reduce overall density, preventing fluid loss into fractures and improving conformance control efficiency.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS9969923B2Sealant compositions for use in subterranean formation operations

Publication Date: 2018.05.15 HALLIBURTON ENERGY SERVICES INC

AI summary

Embodiments herein include methods comprising providing a sealant composition comprising an aqueous base fluid, a crosslinkable polymer composition, and a density segregation prevention agent, wherein the crosslinkable polymer composition comprises a crosslinkable organic polymer and a crosslinker; introducing a particulate density reducing agent into the sealant composition, wherein the particulate density reducing agent causes the sealant composition to adopt a reduced density as compared to the sealant composition without the particulate density reducing agent, thereby creating a reduced density sealant composition; introducing the reduced density sealant composition into a subterranean formation; and crosslinking the reduced density sealant composition into a gel to form a seal in the subterranean formation.