Synthetic base fluids

Phosphate Esters. Phosphate esters are one of the larger volume classes of synthetic base fluids. A typical phosphate ester stmcture where R can be either an aryl or alkyl group is... 

Synthetic antioxidants, 12 60, 10 828 Synthetic-based fluids (SBF), 9 6 Synthetic-based muds, 9 6 Synthetic-based oil soluble sulfonates,... 

Base fluids (BFs) represent the major ingredient of nonaqueous drilling mud systems. They act as the continuous phase in OBMs and SBMs. Oil-based fluids (OBFs) such as diesel and mineral oils have been replaced with synthetic-based fluids (SBFs) because of the deleterious environmental hazards of OBMs. The SBFs contain fatty adds which are usually derived from vegetable oil (e.g., palm oil) or fish oil. SBFs usually constitute about 50-90% by volume of the fluid portion of the SBM [27] and about 20-40 % of the mass of the mud [35]. Ethers, esters, acetals, polymerized olefins (poly-a-olefins, linear a-oleftns, and internal olefins), enhanced mineral oils, and paraffins are used most frequently as SBFs (Table 11.2) in mud formulations [8, 36, 37]. 

A Comparison of the Environmental Performance November 2006 of Olefin and Paraffin Synthetic Base Fluids (SBF). American Chemistry Council, Washington, DC, 2006. 

Abstract The chemical nature and technology of the main synthetic lubricant base fluids is described, covering polyalphaolefins, alkylated aromatics, gas-to-liquid (GTL) base fluids, polybutenes, aliphatic diesters, polyolesters, polyalkylene glycols or PAGs and phosphate esters. Other synthetic lubricant base oils such as the silicones, borate esters, perfluoroethers and polyphenylene ethers are considered to have restricted applications due to either high cost or performance limitations and are not considered here. Each of the main synthetic base fluids is described for their chemical and physical properties, manufacture and production, their chemistry, key properties, applications and their implications when used in the environment. 

Synthetic lubricants have been available for many years in the early 1930s, synthetic hydrocarbon and ester technologies were simultaneously developed in Germany and the United States. Development of a catalytic polymerisation process of olefins in the United States led to the formulation of automotive crankcase lubricants with improved low-temperature performance [1,2]. These products were not commercialised due both to the inherent cost of these new synthetic base fluids and to performance improvements of mineral oil-based lubricants. In Germany, low-temperature performance drove the development of similar products [3], although the main objective was to overcome the general shortage of petroleum base stocks. 

Phosphate esters have been produced commercially since the 1920s and now have important applications as plasticisers, lubricant additives and synthetic-based fluids for hydraulic and compressor oils. Their first use in lubrication was as anti-wear additives. Later developments in aircraft hydraulic control systems, particularly during the Second World War, introduced phosphate esters as less flammable hydraulic fluids. As esters of orthophosphoric acid they have the general formula OP(OR)3, where R represents an aryl or an alkyl group or, very often, a mixture of alkyl and/or aryl components. The physical and chemical properties of phosphate esters can be varied considerably depending on the choice of substituents [59, 60], selected to give optimum performance for a given application. Phosphate esters are particularly used in applications that benefit from their excellent fire-resistant properties, but compared to other base fluids they are fairly expensive. 

The behaviours of mono-, di- and friesters of glycerol oleate were compared as a range of commercial organic friction modifiers in a synthetic base fluid. Of the esters studied, the monoester gave the lowest friction and base fluid polarity had no discernable effect on boundary friction [18]. 

Synthetic-based fluid (SBM) (Otherwise known as Low Toxicity Oil Based Mud or LTOBM)... 

Synthetic-based fluid is a mud where the base fluid is a synthetic oil. This is most often used on offshore rigs because it has the properties of an oil-based mud, but the toxicity of the fluid fumes are much less than an oil-based fluid. This is important when men work with the fluid in an enclosed space such as an offshore drilling rig. 

However, vegetable oils are known to have less oxidative stability than mineral oils and synthetic-base fluids. This is due to the fact that they contain unsaturated fatty acids having allylic hydrogens, which are oxidatively unstable compared with fully saturated hydrocarbons. Saturated vegetable oils, while more oxidatively stable, exhibit... 

Neither oil-based nor synthetic-based fluids exhibited any significant shear viscosity sensitivity to fiber concentration at ambient or elevated temperature. It may be possible for OBM or SBM sweeps to be utilized in the field with no increase in BCD. 

Oil-based and synthetic-based fluids possess high resistance to separation of fibers from the base fluids. This could be attributed to the high yield stress that they exhibit and the presence of internal structure perhaps associated with their invert emulsion character. 

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