Crosslinked Oxidized Xanthan Acidizing Fluid Deep Penetration
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Solution Overview
Problem
Conventional acidizing fluids for subterranean formations face challenges such as limited deep penetration due to rapid spending and the use of synthetic polymers that leave undesirable residues, while natural biopolymers like xanthan have struggled with crosslinking and stability issues.
Innovation Solution
The use of in-situ crosslinked spent acids and crosslinked live acids comprising derivatized xanthan, which acts as a gelling agent to enhance penetration and prevent residue formation, along with optional base fluids and additives for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional acidizing fluids with high acid strength are used, then the acid reacts quickly with formation materials to clean damage, but the acid becomes spent before achieving deep penetration into the formation
Solution Approach 1:
The patent applies preliminary action by pre-crosslinking the xanthan polymer before acid injection to establish a controlled viscosity structure that will maintain acid front stability and enable deep penetration throughout the treatment process
Solution Approach 2:
The patent changes the physical-chemical parameters of the acidizing fluid by using crosslinked xanthan to modify viscosity and gel structure, transforming the fluid from a conventional low-viscosity acid solution to a structured high-viscosity fluid that maintains pressure and enables deep penetration while controlling reaction rate
2Length of moving object
If synthetic polymers are used to gel acidizing fluids for delayed gel effect, then the fluid can penetrate deeper, but undesirable residues are left in the formation
Solution Approach 1:
The patent employs a biodegradable natural polymer (xanthan) that serves as a temporary structuring agent during the acidizing process and then naturally degrades, eliminating the need for removal operations and avoiding long-term residue problems associated with synthetic polymers
Solution Approach 2:
The patent changes the chemical composition from synthetic polymers to natural biopolymers, fundamentally altering the degradation behavior and environmental compatibility of the gelling agent while maintaining the desired rheological properties for deep penetration
3Object-generated harmful factors
If natural biopolymers like xanthan are used for crosslinking, then the fluid is biodegradable and leaves no residue, but crosslinking ability and stability are insufficient
Solution Approach 1:
The patent creates a composite system by combining natural xanthan polymer with metal ion crosslinking agents (such as calcium, zinc, or iron ions) to achieve both the biodegradability of natural polymers and the crosslinking stability required for effective acidizing fluid structure maintenance
Solution Approach 2:
The patent introduces metal ions as intermediary crosslinking agents that bridge the hydroxyl groups of xanthan polymer chains, forming stable coordinate bonds that provide the necessary gel strength and structural stability while maintaining the natural, biodegradable character of the base polymer
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 deeper penetration and longer effective fracture lengths, reduces fluid loss, and avoids leaving residues, effectively stimulating production and dissolving damage in subterranean formations without the drawbacks of conventional acidizing fluids.
Implementation Method 1
in-situ crosslinked spent acids and crosslinked live acids comprising derivatized xanthan
Implementation Method 2
crosslinked oxidized xanthan...acts as a gelling agent
Implementation Method 3
the acid reacts with the formation itself, fines and damage nearest the well bore
Implementation Method 4
dissolving damage in subterranean formations
Data Source
AI summary
Many methods are provided herein including, in one embodiment, a method comprising: providing a fluid that comprises an acid, crosslinked oxidized xanthan, and optionally, a base fluid; placing the fluid in a well bore penetrating a subterranean formation; and allowing the fluid to acidize at least a portion of the formation or damage contained therein. In another embodiment, herein provided is a fluid for subterranean uses comprising an acid and crosslinked, oxidized xanthan.