Diester-Based Drilling Fluid Emulsion for Low Toxicity and Thermal Stability
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Solution Overview
Problem
Conventional oil-based drilling fluids pose environmental concerns due to their pollutant characteristics, particularly in offshore and deep-water drilling, where they are not biodegradable and toxic, necessitating the development of low-toxicity and high-biodegradability alternatives for drilling in challenging conditions.
Innovation Solution
A drilling fluid composition in the form of an inverted emulsion with a predominant oil phase comprising a mixture of diesters A and B, which are thermally stable and biodegradable, replacing traditional paraffinic and olefinic phases, and are formulated with specific diester ratios and additives to maintain stability and lubricity under high pressure and temperature conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional oil-based drilling fluids (paraffins, olefins, kerosene) are used, then lubricity and drilling performance are maintained, but environmental pollution and toxicity increase
Solution Approach 1:
The patent changes the chemical composition parameters of the oil phase by using diesters with specific carbon chain lengths (C12-C24) and molecular structures, replacing conventional paraffinic and olefinic bases. This parameter change maintains the necessary lubricity and film strength while improving biodegradability and reducing aromatic content to below 5%, thereby resolving the contradiction between drilling performance and environmental harm.
Solution Approach 2:
The invention uses composite ester formulations combining different diester types (e.g., dibutyl sebacate, diisopentyl adipate, dibutyl glutarate) to create an oil phase that integrates multiple beneficial properties: adequate viscosity, high lubricity, thermal stability, and enhanced biodegradability. This composite approach allows simultaneous achievement of drilling performance requirements and reduced environmental impact.
2Object-affected harmful factors
If aromatic-free oils are used to reduce toxicity, then environmental compatibility improves, but lubricity and film strength deteriorate
Solution Approach 1:
The patent optimizes the molecular structure parameters of the ester molecules by selecting specific carbon chain lengths (C12-C24) and ester linkage configurations that provide adequate film strength and lubricity. The controlled presence of unsaturation (0-40%) and specific acid/alcohol combinations enable the aromatic-free oil to maintain necessary tribological properties while achieving low toxicity and high biodegradability.
3Object-affected harmful factors
If vegetable oils and animal fats are used as biodegradable alternatives, then environmental compatibility improves, but thermal stability and oxidation resistance worsen
Solution Approach 1:
The patent modifies the thermal stability parameters by using refined ester formulations with controlled unsaturation levels (0-40%) and specific molecular weight distributions. The selection of diesters with longer carbon chains and saturated or partially saturated structures provides resistance to thermal degradation and oxidation while maintaining biodegradability, thus resolving the contradiction between environmental compatibility and thermal stability.
4Object-affected harmful factors
If inverted emulsion formulation is used, then water solubility and biodegradability improve, but emulsion stability and filler precipitation worsen
Solution Approach 1:
The patent uses composite emulsifier systems combining anionic, cationic, and non-ionic surfactants in specific ratios to create a stable inverted emulsion. This composite emulsifier approach provides sufficient interfacial stabilization to prevent filler precipitation and phase separation while maintaining the water-dispersible nature that enables biodegradability, thus resolving the contradiction between emulsion stability and biodegradability.
Data Source
AI summary
The present patent application discloses a low toxicity and high biodegradability drilling fluid composition in the form of an inverse emulsion containing an oil phase and an aqueous phase, wherein said oil phase comprises a mixture of at least two diesters obtained from the esterification of a carboxylic acid and an alcohol. The selected diesters are suitable for use in drilling of crude oil or natural gas deposits, exhibiting good stability in the formulations assessed under conditions of high pressure and high temperature and in the presence of divalent salt brines.