Wells, oil

It appears that corrosion in high-pressure flowing wells that produce pipeline oil has become almost commonplace in many areas. Three methods are used to combat this corrosion as follows  

Coated mbing has found most favor. Epoxy paints and powder epoxy coatings should be used. 

These wells handle oil with higher sulfur contents than sweet wells and represent a more corrosive environment. In high- HjS wells there may be severe attack on the casing in the upper part of the well where the space is filled with gas. Water vapor condenses in this area and picks up HjS and COj. 

Corrosion is reduced by inhibitors that are injected continuously or periodically depending on the well corrosivity. 

Condensate wells handle fluids (gas containing dissolved hydrocarbons) at pressures up to 680 bars (10 000lb/in ). Depths run up to 4570m (15 000 ft). 

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Oil well - completed Oil bearing reservoir - not completed + In combination with well symbol e.g. 

The above examples are shown for water coning and cusping. The same phenomena may be observed with overlying gas being pulled down into the producing oil well. This would be called gas coning or cusping. 

If water or gas breakthrough occurs (in an oil well) from a high permeability layer it can dominate production from other intervals. Problems such as this can sometimes be prevented by initially installing a selective completion string, but in single string... 

The techmque was first employed, in real-world conditions, for monitoring external corrosion in the large diameter steel tubing used for oil well casings. In the late fifties, T.R. Schmidt at Shell Developments, pioneered the technique in those demanding applications, although the technique itself was invented, by W.R. MacLean, (Ref. 1) somewhat earlier. T.R Schmidt has written a history (Ref. 2) of much of the early work in the technology, which contains many references, others which may be of interest are held on the NTIAC database (Ref 3). 

A much more forgiving yet limited extraction method can be used to isolate phenol species such as eugenol and chavicol. You see farther back in this chapter where one can use dilute NaOH to remove eugenol from sassafras oil Well, why not use it to isolate the damn things for further research. It works like a charm ... 

Uses. Propargyl alcohol is a component of oil-well acidizing compositions, inhibiting the attack of mineral acids on steel (see Corrosion and CORROSION control). It is also employed in the pickling and plating of metals. 

Nitrile mbber finds broad application in industry because of its excellent resistance to oil and chemicals, its good flexibility at low temperatures, high abrasion and heat resistance (up to 120°C), and good mechanical properties. Nitrile mbber consists of butadiene—acrylonitrile copolymers with an acrylonitrile content ranging from 15 to 45% (see Elastomers, SYNTHETIC, NITRILE RUBBER). In addition to the traditional applications of nitrile mbber for hoses, gaskets, seals, and oil well equipment, new applications have emerged with the development of nitrile mbber blends with poly(vinyl chloride) (PVC). These blends combine the chemical resistance and low temperature flexibility characteristics of nitrile mbber with the stability and ozone resistance of PVC. This has greatly expanded the use of nitrile mbber in outdoor applications for hoses, belts, and cable jackets, where ozone resistance is necessary. 

Explosives for Use at High Temperatures. Explosives that can withstand prolonged exposure to elevated temperatures without detonating find considerable use ia such appHcations as detonators for deep oil wells, space travel, and componentry for specialised appHcations. The explosives developed for this purpose are primarily nitroaromatic compounds, the most important of which are hexanitrostilbene and... 

Fluorine reacts with the halogens and antimony to produce several compounds of commercial importance antimony pentafluoride [7783-70-2J, bromine trifluoride [7787-71 chlorine trifluoride [7790-91 -2J, and iodine pentafluoride [7783-66-6J. Chlorine trifluoride is used in the processing of UF (see Uraniumand uranium compounds). Bromine trifluoride is used in chemical cutting by the oil well industry (see Petroleum). Antimony and iodine pentafluorides are used as selective fluorinating agents to produce fluorochemical intermediates (see Fluorine compounds, inorganic). 

The earliest oil marketed in the United States came from springs at Oil Creek, Pennsylvania, and near Cuba, New York. It was used for medicinal purposes and was an article of trade among the Seneca Indians. At that time, the term Seneca Oil appfied to all oil obtained from the earth. The first oil well was drilled in 1859 in Pennsylvania to a depth of 21.2 m for Seneca Oil Co. It produced 280 t (2000 bbl) in that year. This was the beginning of cmde oil production. 

Aqueous Hydrochloric Acid. Muriatic acid consumption in 1993 was about 1.57 million metric tons (100% basis). The largest captive use of aqueous HCl is for brine acidification prior to electrolysis in chlorine/caustic cells and the largest merchant markets for HCl are steel pickling and oil-well acidizing, which accounted for 25 and 16% of merchant production, respectively, during 1989. 

Electric Submersible Oil Well Pump Cable. These cables are rated up to 5 kV and are designed for highly corrosive oil wells that besides oil also contain brine and other harsh chemicals as well as gases under high pressure and high temperatures (6). Insulations can be based on polypropylene for low temperature wells or on ethylene—propylene mbber which is compounded with special ingredients in order to resist the environments of high temperature wells (Fig. 4). 

Fig. 4. Submersible oil well pump cable. A, SoHd copper conductor B, EPR-based insulation C, chemical barrier D, lead sheath E, filler E, galvanised...

Petroleum. Apart from its use ia petrochemicals manufacture, there are a number of small, scattered uses of lime ia petroleum (qv) production. These are ia making red lime (drilling) muds, calcium-based lubricating grease, neutralization of organic sulfur compounds and waste acid effluents, water treatment ia water flooding (secondary oil recovery), and use of lime and pozzolans for cementing very deep oil wells. 

As the natural pressures in the reservoir decrease, oil production declines. The oil well may then be placed on-pump to maintain production at economic levels. The pump draws oil to the surface and lowers the height of the fluid column ia the wellbore. The pressure of a column of fluid can decrease the rate of fluid entry into the wellbore. 

Primary production typically recovers 10—25% of the oil originally ia the reservoir. Efficiency of primary production is related to oil properties, reservoir properties, geometric placement of oil wells, and the drilling and completion technology used to drill the wells and prepare them for production. Pumping the well can maintain production at economic levels for years. 

Eig. 2. Cychc steam stimulation of an oil well (a) steam, injected into a well over a period of days or weeks in a heavy oil reservoir, introduces heat (huff) that, coupled with (b), alternate soak periods lasting a few days to allow (c) a production phase of weeks or months (puff), thins the oil. This process may... 

Organophosphoms compounds, primarily phosphonic acids, are used as sequestrants, scale inhibitors, deflocculants, or ion-control agents in oil wells, cooling-tower waters, and boiler-feed waters. Organophosphates are also used as plasticizers and flame retardants in plastics and elastomers, which accounted for 22% of PCl consumed. Phosphites, in conjunction with Hquid mixed metals, such as calcium—zinc and barium—cadmium heat stabilizers, function as antioxidants and stabilizer adjutants. In 1992, such phosphoms-based chemicals amounted to slightly more than 6% of all such plastic additives and represented 8500 t of phosphoms. Because PVC production is expected to increase, the use of phosphoms additive should increase 3% aimually through 1999. 

Enzymes for Extreme Conditions. The possibihty of using enzymes from extremophiles, which thrive in oil wells, hot temperatures, freezing conditions, etc, is being explored for the removal of environmental contaminants and survival at extreme temperatures (see Wastes, HAZARDOUS WASTE TREATlffiNT BlORETffiDIATION (SuPPLET NT)). 

Alkylbenzyldimethyl quaternaries (ABDM) are used as disinfectants (49) and preservatives. The most effective alkyl chain length for these compounds is between 10 and 18 carbon atoms. Alkyltrimethyl types, alkyl dimethylbenzyl types, and didodecyl dimethyl ammonium chloride [3401-74-9] exhibit excellent germicidal activity (151—159). Dialkyldimethyl types are effective against anaerobic bacteria such as those found in oil wells (94—97). One of the most effective and widely used biocides is didecyl dimethyl ammonium chloride [7173-57-5]. 

Petroleum Recovery. Steam is iajected iato oil wells for tertiary petroleum recovery. Steam pumped iato the partly depleted oil reservoirs through iaput wells decreases the viscosity of cmde oil trapped ia the porous rock of a reservoir, displaces the cmde, and maintains the pressure needed to push the oil toward the production well (see Petroleum, enhanced recovery). Steam is also used ia hot-water extractioa of oil from tar sands (qv) ia the caustic conditioning before the separatioa ia a flotatioa tank (35). 

Nonreplenishable (fossil) groundwater can be tapped, but such extraction depletes reserves in much the same way as extractions from oil wells do. The terrestrial renewable freshwater supply, RFITTj, equals precipitation on land, which then subdivides into two major segments evapotranspiration from the land, and mnoff to the sea, T. Because groundwater and surface water are often hydrauhcaHy coimected, soil infiltration and groundwater... 

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