Sour wells

Titanium alloys suffer crevice corrosion in hot aqueous chloride media, but the alloy containing molybdenum, 3A1-8V-6 Cr-4Zr-4 Mo has good resistance to crevice corrosion and is successfully used in hot sour well and geothermal brine... 

Sulfide stress cracking (SSC), a form of hydrogen embrittlement, is a serious problem in the oil industry because of the potentially catastrophic nature of a failure of high strength carbon steel casing, tubing, or surface equipment. Inhibition is not a reliable means to prevent SSC because treatment interruptions could lead to failure. Control of SSC is accomplished by carefiil specification and quality control of equipment for sour wells. Materials that are acceptable for service in sour enviromnents are defined in NACE Standard MR0175. This standard is updated annually. 

The sourest gas plant in Canada was opened at Harmattan, near Shantz, which had a hydrogen sulfide content of 52%, by Canadian Superior Oil Limited (purchased by Mobil Oil in 1984) in 1966. While Harmattan is the sourest natural gas processing plant, even more sour wells have been discovered. In the U.S., a very sour well (H2S = 78%) was discovered at Black Creek, near Biloxi, Mississippi. Philips Petroleum and Pan American Petrolerrm investigated the production of sulfur from this site, but decided not to proceed with commercialization after the price of sulfur had fallen in 1969. 

Sweet wells do not contain hydrogen sulfide, whereas sour wells do. The source of CO2 can be mineral dissolution or a by-product of the petroleum-forming process. The source of H2S can be dissolution of mineral deposits in the rocks, a by-product of the petroleum-forming process, or bacterial action at any time in the history of the petroleum deposit. Oxygen always originates from air and can only come in contact with petroleum fluids after the recovery process begins. It does not exist in the undisturbed hydrocarbon deposit. 

Sour corrosion. In sour wells, hydrogen sulfide is the primary corrosive agent, and frequently carbon dioxide is present as well. The presence of various iron sulfides in the corrosion products at different concentrations of hydrogen sulfide has been identified. Based on this evidence the net corrosion reaction due to hydrogen sulfide can be written as follows ... 

Corrosion inhibitors used in the past to combat corrosion in sour wells include aldehydes, cyanamide thiourea, and urea derivatives. The most widely used inhibitors are organic amines. Although organic amines are known to be less effective inhibitors in acid solution, inhibition by amines in the presence of hydrogen sulfide is greatly... 

In the treatment of sour wells (wells produdng H S gas), the possibility of iron sulfide (FeS) precipitation exists. FeS precipitates at a pH of about 2, which poses a potential problem as acid spends and pH rises. Hall and Dill have shown that a mixture of nitrilotriacetic add (NTA), mutual solvent (EGMBE), and a sulfide modifier can control the precipitation of EeS. Sulfide modifier additives are available from service companies and may be included in the iron control additive package. 

Uses Surfactant, film-former and corrosion inhibitor for sour wells in oil systems Features Builds strong org. layer protecting the internal metallic surfaces not recommended for very high temps. does not contain chlorides and halides, which can affect refinery woite incompat.with anionics Properties Transparent liq. oil-sol. water-disp. insol. in brine water and methanol dens. 0.826-0.835 g/cm f.p. < - 35 C b.p. > 200 C. flash pt. 64 C DanoxDB-1 [KaoCoq). SA]... 

A persistent idea is that there is a very small number of flavor quaUties or characteristics, called primaries, each detected by a different kind of receptor site in the sensory organ. It is thought that each of these primary sites can be excited independently but that some chemicals can react with more than one site producing the perception of several flavor quaUties simultaneously (12). Sweet, sour, salty, bitter, and umami quaUties are generally accepted as five of the primaries for taste sucrose, hydrochloric acid, sodium chloride, quinine, and glutamate, respectively, are compounds that have these primary tastes. Sucrose is only sweet, quinine is only bitter, etc saccharin, however, is slightly bitter as well as sweet and its Stevens law exponent is 0.8, between that for purely sweet (1.5) and purely bitter (0.6) compounds (34). There is evidence that all compounds with the same primary taste characteristic have the same psychophysical exponent even though they may have different threshold values (24). The flavor of a complex food can be described as a combination of a smaller number of flavor primaries, each with an associated intensity. A flavor may be described as a vector in which the primaries make up the coordinates of the flavor space. 

The practical importance of the higher sulfanes relates to their formation in sour-gas wells from sulfur and hydrogen sulfide under pressure and their subsequent decomposition which causes well plugging (134). The formation of high sulfanes in the recovery of sulfur by the Claus process also may lead to persistance of traces of hydrogen sulfide in the sulfur thus produced (100). Quantitative deteanination of H2S and H2S in Claus process sulfur requires the use of a catalyst, eg, PbS, to accelerate the breakdown of H2S (135). 

Most natural gas is substantially free of sulfur compounds the terms. sweet and. sour are used to denote the absence or presence of HgS. Some wells, however, dehver gas containing levels of hydrogen sulfide and other sulfur compounds (e.g., thio enes, mercaptans, and organic sulfides) that must be removed before transfer to commercial pipehnes. Pipehne-company contracts typically specify maximum allowable Emits of impurities HgS and tot sulfur compounds seldom exceed 0.023 and 0.46 g/m (1.0 and 20.0 gr/100 std fF),... 

Most of the early work carried out in relation to these aspects of the problem used nitrates as the cracking environment where low-strength steels have been the objects of interest. Consequently most of what follows refers to cracking in boiling concentrated nitrate solutions except where otherwise stated. The medium and higher strength steels, such as involved in sour oil well equipment and other applications, are more frequently tested in chloride- or sulphide-containing environments related to service conditions, but the failure of these steels is dealt with elsewhere (see Section 8.4). 

The release of gas causes the batter to rise. The weak acids are provided by the recipe, generally in the form of lactic acid from sour milk or buttermilk, citric acid from lemons, or the acetic acid in vinegar. Baking powder contains a solid weak acid as well as the hydrogen carbonate, and carbon dioxide is released when water is added. 

When John told his mother that I was with child, she had perforce to give us joy, but the sourness lingered in her voice. I got little help from her in the first, sickly weeks, but Mai said that the sickness heralded a boy, and this hope strengthened me to ignore her. By the fourth month I was in better health, and all still seemed to be well. 

Leahey DM, Schroeder MB. 1986. Predictions of maximum ground-level hydrogen sulfide concentrations resulting from two sour gas well blowouts. J Air Pollut Control Assoc 36 1147-1149. 

A sour natural gas stream can be anaerobically desulfurized by a process, which employs a consortium of chemoautotrophic bacteria (ATCC 202177). The H2S and other sulfur species are converted into elemental sulfur, which is recovered as a product [287], The process conditions involve pressures lower than 1000 psi and temperatures up to 60°C. Sulfur content might be diminished from 10,000 ppm H2S to pipeline standards of <4ppm. Further, C02 content can be reduced as well from levels as high as 10% to <2%. 

Sour dough bread has a range of flavours that are not present in other bread also it keeps relatively well. The keeping properties, no doubt, originate from some of the products of the side-reactions that have taken place in the dough. There is no need to add propionic acid as a mould inhibitor as some is likely to be present naturally. Quite possibly, some of the substances produced by the fermentation would not be permitted as additives ... 

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