Oil and gas wells

Alkanolamine Chelates. Alkanolamine chelates, which are prepared by reaction of tetraalkyl titanates with one or more alkanolamines, are used primarily in cross-linking water-soluble polymers (qv) (see Alkanolamines) (104). The products are used in thixotropic paint emulsion paints, in hydrauhc fracturing and drilling of oil and gas wells, and in many other fields. The stmcture of... 

Production and Consumption. About 80% of the world s barite production is used as a weighting agent for the muds ckculated in rotary drilling of oil and gas wells (see PETROLEUM, DRILLING FLUIDS AND OTHER OIL RECOVERY CHEMICALS). Table 2 shows the U.S. production—consumption balance. The 1988 demand for barite increased nearly 40% over that recorded in 1987. However, by the end of 1988, oil prices had declined and renewed economic uncertainties depressed exploration and development activity. Barite demand fell accordingly and imports of lower cost foreign product exceeded domestic production. 

Process Description The installation of deep wells for the injection of wastes closely follows the practices used for the drilling and completion of oil and gas wells. 

The hydrocarbon methane (CH,) is the major component of natural gas (around 90 percent) that is found in oil and gas wells throughout the world. Since the begiiitiiiig of time, methane has also been produced by a number of biological sources—both natural and huiiiaii—by the decoiiipositioii of organ-... 

New Mexico occupational health and safety recommended practices for oil and gas well drilling and service operations, State of New Mexico Environmental Improvement Division Report No. EID/OHS-82/2, 1982. 

Additionally, there may be COj, HjS or bacteria present, all of which substantially increase the corrosivity of formation waters. Furthermore, whilst in a young oil and gas well the levels of produced formation waters (termed watercut ) may well be very low, at later stages of maturity, the watercut may reach values in excess of 90%. Consequently, oil and gas production systems may often be subject to increasing corrosion risk with time. 

It should be noted that there are still many deficiencies in the science and technology of corrosion monitoring, mainly in the areas of localised corrosion (pitting) and the inability to monitor at inaccessible sites such as downhole (oil and gas wells) and subsea installations (satellite wells and pipelines). 

Corrosive wear results from a chemical reaction of the wear surface with the environment. In this section, only corrosion that occurs in conjunction with mechanical wear is considered. Purely corrosive wear is reviewed in Sec. 4.0 below. The chemical resistance of a given coating material must be assessed if the application involves a corrosive environment. A typical example is the environment found in deep oil and gas wells (over 500 m.), which usually contain significant concentrations of CO2, H2S, and chlorides. The corrosive effect of these chemicals is enhanced by the high temperature and pressure found at these great depths. 

A fluid loss additive useful in cementing oil and gas wells is a blend [423,424,1015] of a copolymer of acrylamide/vinyl imidazole. The second component in the blend is a copolymer of vinylpyrrolidone and the sodium salt of vinyl sulfonate. Details are given in Table 2-2. The copolymers are mixed together in the range of 20 80 to 80 20. Sodium or potassium salts or a sulfonated naphthalene formaldehyde condensate can be used as a dispersant. 

Furthermore, an a,P-ethylenically unsaturated aldehyde together with organic amines will form intermediate products, which are further reacted with a carboxylic acid, an organic halide, or an epoxide-containing compound [ 1760]. The final products are suitable corrosion inhibitors for preventing corrosion of steel in contact with corrosive brine and oil and gas well fluids. 

An inhibitor during drilling and servicing of oil and gas wells is a condensate of aminopyrazine and an epoxide compound, such as the glycidyl ether of a mixture of Cn to C14 alkanols [604]. 

The use of polyisoprene or butadiene-styrene latex with bentonite or chalk filler and polyoxypropylene as an additive has been used in a plugging solution for oil and gas wells [1042]. The solution can be pumped but coagulates within the formation at temperatures of 100° C within 2 hours. This causes a reduction in permeability. The formulation is particularly useful in deep oil deposits. 

Small amounts of pyridine bases increase the corrosion resistance of cement stone without any associated loss of strength [1016]. The use of nitrilo-trimethyl phosphonic acid and an adduct between hexamethylene tetramine and chlorinated propene or butene improves the adhesion to the metal, hardening times, mobility, and strength [ 1770]. The latter adducts are further claimed to be useful as additives in cementing oil and gas wells in salt-bearing strata [1768]. 

Granulated fly ash [6] can substitute for Portland cement to an extent of 40% to 60%. Fly ash is used in granulated form and has a moisture content around 10% to 20%. The formulation can be used for cementing oil and gas wells within a temperature range of 20° to 250° C. The solution has reduced water absorption and increased sedimentation stability. A formulation [1388] is shown in Table 18-2. Hydrosil (Aerosil) is used to increase the adhesion of the produced cement rock to the casing string. It also reduces the density and water absorption. 

A plugging slurry for oil and gas well drilling is given in Table 18-7 [1441]. It is formed by adding water to the Portland cement suspension containing the other three constituents. The bentonite clay powder is premixed with water... 

In oil and gas well cementing operations, polyethyleneimine phosphonate-derivative dispersants enhance the flow behavior of the cement slurry [422]. The slurry can be pumped in turbulent flow, thereby forming a bond between the well casing and the rock formation. 

S. A. Abramov, A. P. Krezub, N. A. Mariampolskij, E. S. Bezrukova, and M. A. Egorov. Plugging solution for cementing of oil and gas wells—contains plugging Portland cement and granulated fly ash, of specified moisture content, as active additive. Patent SU 1802089-A, 1993. 

V. E. Akhrimenko, V. B. Levitin, L. V. Palij, Y. Ya. Taradymenko, and V. P. Timovskij. Plugging solution for cementing oil and gas wells— contains Portland cement, expanding additive based on sintered calcium oxide, amino-formaldehyde or acetone-formaldehyde resin and water. Patent SU 1776765-A, 1992. 

R. A. Allakhverdiev, B. Khydyrkuliev, and N. V. Reznikov. Plugging solution for repairing oil and gas wells-contains plugging Portland cement, isobutanol, water and liquid metal alloy of gallium, indium and tin, to increase strength of cement stone. Patent SU 1802082-A, 1993. 

V. A. Blazhevich, D. A. Khisaeva, V. G. Umetbaev, and I. V. Legostaeva. Polymer plugging solution for oil and gas wells—contains urea-formaldehyde resin, and aluminium chloride containing waste of isopropylbenzene production as acid hardener. Patent SU 1763638-A, 1992. 

V. P. Bortsov, A. A. Baluev, and S. N. Bastrikov. Plugging solution for oil and gas wells—contains Portland cement, aluminum powder, fish scale, anionic and nonionic surfactant, plasticiser and water. Patent RU 2078906-C, 1997. 

V. G. Fil, L. A. Ezlova, V. D. Kovalenko, D. A. Kostenko, B. I. Navrot-skij, V. V. Koptenko, and S. P. Dombrovskaya. Plugging solution for oil and gas wells—comprises Portland cement, asbestos reinforcing component, mixture of sodium chloride and sulphate mineral component, fly ash and water, (rus). Patent RU 2013525-C, 1994. 

J. J. Fitzgibbon. Sintered, spherical, composite pellets prepared from clay as a major ingredient useful for oil and gas well proppants. Patent CA 1232751, 1988. 

A. K. Khaund. Improved stress-corrosion resistant proppant for oil and gas wells. Patent EP 207427,1987. 

Z. N. Kudryashova, B. V. Mikhajlov, A. P. Tamavskij, S. R. Khajrullin, V. M. Mustafaev, and P. F. Tsytsymushkin. Plugging solution for cementing oil and gas wells—contains plugging cement, ash, additional clay powder and crude light pyridine bases, and water. Patent SU 1765366-A, 1992. 

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