Thermochemical Wellbore Cleaning Method
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Solution Overview
Problem
Conventional methods for well cleanup, such as using mud acids, are inefficient and environmentally harmful, and fail to effectively remove drilling fluid residues and scale buildup, leading to reduced well productivity and injectivity, especially in horizontal wells.
Innovation Solution
A method involving pre-treatment injectivity testing, acid cleaning, gel jetting, and the use of thermochemical mixtures to generate heat and pressure, which solubilizes and removes wellbore damage, improving injectivity and reducing the need for toxic chemicals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional mud acids are used for well cleanup, then some cleaning effect is achieved, but the method is inefficient, environmentally harmful, and fails to effectively remove drilling fluid residues and scale buildup
Solution Approach 1:
The patent changes the chemical parameters of the cleaning fluid by using biodegradable acids (acetic acid, propionic acid, butyric acid) instead of conventional mud acids (hydrofluoric acid, hydrochloric acid). This parameter change achieves effective removal of drilling fluid residues and scale buildup while being environmentally friendly and biodegradable, thus improving well injectivity without environmental harm.
Solution Approach 2:
The patent converts the harmful effect of acid corrosion into a beneficial cleaning mechanism. The biodegradable acids are designed to corrode and remove the harmful scale buildup and drilling fluid residues from wellbore surfaces, while the acids themselves are environmentally benign and biodegradable, thus converting a potentially harmful chemical process into a beneficial cleaning action.
2Reliability
If drilling fluid is used to maintain borehole stability, then borehole stability is achieved, but filter cake and scale buildup form that reduce well productivity
Solution Approach 1:
The patent applies preliminary cleaning action before the well completion process. The biodegradable acid formulation is injected into the wellbore to pre-remove filter cake and scale buildup that formed during drilling operations. This preliminary action restores wellbore permeability and prepares the well for optimal productivity while maintaining borehole stability through controlled acid-rock reactions.
Solution Approach 2:
The biodegradable acid formulation acts as an intermediary substance that selectively dissolves the harmful filter cake and scale buildup without damaging the underlying formation. The acids serve as a mediator between the wellbore environment and the formation, removing the impermeable layers that block fluid flow while maintaining the structural integrity of the borehole.
3Loss of energy
If filter cake is formed to prevent filtrate leak-off, then fluid loss control is achieved, but an impermeable layer forms that increases resistance to formation fracturing
Solution Approach 1:
The patent replaces the mechanical barrier approach (filter cake as a physical barrier) with a chemical cleaning approach. Instead of relying on the mechanical integrity of the filter cake to prevent fluid loss, the biodegradable acids chemically dissolve the filter cake and scale buildup, converting the mechanical barrier into a chemical removal process that restores wellbore permeability without compromising formation strength.
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 method significantly increases well injectivity by 3000% and effectively removes wellbore damage without causing microfractures, reducing the need for sidetracking and shortening flowback time, while being more environmentally friendly.
Implementation Method 1
A method involving pre-treatment injectivity testing, acid cleaning, gel jetting, and the use of thermochemical mixtures to generate heat and pressure, which solubilizes and removes wellbore damage
Implementation Method 2
injecting a thermochemical mixture into the well bore, thereby increasing temperature and pressure and cleaning build up from the well bore
Implementation Method 3
performing an acid cleaning of one or more of a coiled tubing and the well bore using a hydrochloric acid mixture of 7 to 15 wt % hydrochloric acid
Data Source
AI summary
A method for the removal of well bore damage, the method including performing an acid cleaning of one or more of a coiled tubing and the well bore using a hydrochloric acid mixture of 7 to 15 wt % hydrochloric acid and displacing the hydrochloric acid mixture with a first fresh water stream. After acid cleaning, a composition comprising at least 10 wt % acetic acid into the wellbore is injected into the wellbore. After injecting acetic acid, gel jetting of the well is performed with a gel mixture, and the gel mixture is subsequently displaced with a second fresh water stream. After gel jetting, an organic solvent mixture is injected into the well bore and allowing the organic solvent mixture to soak for 2 to 6 hours. Finally, a thermochemical mixture is injected into the well bore, thereby increasing temperature and pressure and cleaning build up from the well bore.