Oxidized Polyethylene Waxes for High-Temperature Drilling Fluid Rheology
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing rheological additives for drilling fluids, particularly those based on oxidized polyethylene, face challenges such as incomplete dissolution during coating manufacturing, particle-induced gloss issues, and incompatibility with oil-based drilling fluids, which affect the stability and performance of drilling fluids at high temperatures.
Innovation Solution
The use of both low-density oxidized polyethylene (LDoxPE) and high-density oxidized polyethylene (HDoxPE) waxes as rheological additives in oil-based drilling fluids, combined with organoclays, to create a stable shear thinning rheology that persists at high temperatures, improving suspension and pumpability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If LDoxPE is used as rheological additive in coating manufacturing, then viscosity control is improved, but incomplete dissolution occurs at manufacturing temperatures
Solution Approach 1:
The patent changes the temperature parameter by using cryogenic temperatures to grind the LDoxPE, creating a fine powder that can then dissolve completely at elevated coating manufacturing temperatures. This parameter change resolves the contradiction by enabling both complete dissolution and effective viscosity control.
Solution Approach 2:
The patent segments the LDoxPE into fine particles through cryogenic grinding, breaking down the material into smaller units that can more completely dissolve at processing temperatures while still providing the desired rheological control in the final coating.
2Stability of the object's composition
If cryogenic grinding is used to disperse LDoxPE, then particle dispersion is improved, but manufacturing cost increases
Solution Approach 1:
The patent uses cryogenic grinding as an intermediary process that creates a fine powder intermediate form. This intermediate can then be easily dispersed in the coating formulation at lower costs, separating the high-energy size reduction step from the final dispersion step.
3Ease of operation
If volatile solvent dispersions of LDoxPE are used, then rheological control is improved, but compatibility with oil-based drilling fluids is lost
Solution Approach 1:
The patent changes the chemical composition parameter by replacing volatile organic solvents with water-based or oil-compatible formulations. This allows the LDoxPE dispersion to maintain its rheological control functionality while becoming compatible with oil-based drilling fluid systems.
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 combination of oxidized polyethylene waxes and organoclays provides thermal stability and a flat rheological profile, enhancing the suspension of weighting agents and drill cuttings while maintaining fluid pumpability and penetration rate at elevated temperatures, making it suitable for high-pressure, high-temperature applications.
Implementation Method 1
The MPA type LDoxPE dispersions are added to the pigment grind during the coating production process wherein temperatures can reach 125 F. The high shear dispersion and elevated temperature in the pigment grind ensure complete incorporation of the LDoxPE dispersion. Once fully incorporated into the coating the LDoxPE forms a loose network of LDoxPE molecules that imparts very low shear rate viscosity to the coating while not appreciably increasing high shear viscosity
Implementation Method 2
The oxidation of the PE introduces carboxylic acid sites on the PE molecule. The degree of oxidation of the PE is expressed in terms of acid number. Acid number is defined as, 'mg KOH required to neutralize the acidity in 1 gram of oxPE.' In industrial applications this acidity can be neutralized with KOH, NaOH, or amines in order to help emulsify the oxPE in water.
Data Source
AI summary
The invention describes the use of both low-density oxidized polyethylene wax (LDoxPE) and high-density oxidized polyethylene wax (HDoxPE) as rheological additives in oil-based drilling fluids (OBF). This includes both 100% oil and invert emulsion drilling fluids in which the continuous phase is diesel oil, mineral oil, synthetic esters, synthetic olefins, or other organic fluid.