Corrosion inhibitors producing wells

Corrosion Inhibitors. The corrosion inhibitors used in diesel fuel ate generally similar to those used in gasoline and, like the latter, produce an effect primarily by surface action. If amine additives ate used for detergency, these may provide some corrosion protection as well. 

A corrosion inhibitor that is the adduct of a carbonyl compound, an amine, and a thiocyanate has been described [1431]. The product provides protection against ferrous corrosion in severe environments. 500 ppm by weight is sufficient. The inhibitor is employed in wells producing both oil and water and in high-temperature environments around 120° C. 

The treatment of bilge water and emulsions resembles that of the treatment of oil field brines and produced water. Chen et al. [25], using ferric chloride and other chemicals to enhance the performance of Membralox 0.2, 0.5 and 0.8 pm membranes, describe permeate fluxes between 1400 and 34001/m h. Without pretreatment however severe fouling occurred as well as break-through of oil. Zaidi et al. [26] report about the continuation of this work. They quote fluxes between 800 and 12001/m h, but also mention substantial lower fluxes in long term pilot tests using 0.8 pm membranes. In addition they indicate a drop in permeate flux caused by conditions of low pH, the presence of sea water, corrosion inhibitor, oil slugs or flow variations. 

It is usefiil to consider the case of an installation of a subsea gathering system for a natural gas production field. The pipeline design for a new gas production facility consisted of 20 cm diameter subsea gathering lines (flow lines) emptying into a 19 km, 50 cm diameter subsea transmission gas pipeline. The pipeline was to bring wet gas from an offshore producing area to a dehydration facility on shore. The internal corrosion was estimated to be 300-400 mpy. The corrosion mitigation options considered were (i) carbon steel treated with a corrosion inhibitor (ii) internally coated carbon steel with a supplemental corrosion inhibitor (iii) 22% Cr duplex stainless steel (iv) 625 corrosion-resistant alloy (CRA). The chance for success was estimated from known field histories of each technique, as well as the analysis of the corrosivity of the system and the level of sophistication required for successful implementation (Table 4.42). 

Fatty amines and diamines can be used for corrosion inhibition in oil-producing wells. Typically, these products are dispersed as salts of organic acids such as fatty acids or petroleum sulfonic acids. Fatty amines and diamines have also been used as corrosion inhibitors in the transportation and storage of petroleum products. Quaternary ammonium salts, including dialkyldimethy-lammonium, monoalkyltrimethylammonium and mono-alkyldimethylbenzylammonium, are good corrosion inhibitors. 

Tertiary amyl alcohol is a chemical intermediate for producing corrosion inhibitors, additives for fuels and lubricants, peroxy esters, plasticizers, and pharmaceuticals, and has been used as a stabilizer for chlorinated solvents. Cyclohexanol is another alcoholic intermediate used in the production of pharmaceuticals, agricultural chemicals, plasticizers, rubber chemicals, and cyclohexylamine. It has been used as a stabilizer for soaps and synthetic detergents as well as a solvent for textile dyes. 

In this case, the ion-association model predicted that the connate water would require a minimum dilution with boiler feedwater of 15 percent to prevent halite precipitation (Fig. 8.23). The model also predicted that over-injection of dilution water would promote barite (barium sulfate) formation (Fig. 8.24). Although the well produced F1,S at a concentration of 50 mg/L, the program did not predict the formation of iron sulfide because of the combination of low pH and high temperature. Boiler feedwater was injected into the bottom of the well using the downhole injection valve normally used for corrosion inhibitor injection. Injection of dilution water at a rate of 25 to 30 percent has allowed the well to produce successfully since startup. Barite and iron sulfide precipitation have not been observed, and plugging with salt has not occurred. 

The films contain soluble chromates that act as corrosion inhibitors that provide a modest improvement in corrosion resistance. As with phosphatizing, the film produced serves as an excellent coating base. Indeed, it can be difficult to make most polymeric coatings adhere to the nonferrous alloys without such a treatment. Epoxy primer, for example, which does not adhere well to bare aluminum, adheres very well to chemical conversion coatings. Recent concerns with the toxicity of the hexavalent chromium used in chromating have, however, limited its usage. 

Remember that a corrosion inhibitor program is basically a coating treatment. The amount of inhibitor required depends upon the amount of metal to be protected, not upon the volume of fluid produced by the well. The amount of fluid produced determines the frequency of treatment, although it is probable that no well should go longer than three months between corrosion treatments. 

Uses Corrosion Inhibitor for water floods, packer fluids, producing oil wells, gas wells, pipelines, foamer additives for completion work, wetting agents, surfactants, cleaners, and water treatment... 

Alicyclic amines are used as pesticides, plasticizers, explosives, inhibitors of metal corrosion and sweetening agents as well as having uses in the pharmaceuticals industry. Aniline hydrogenation has been studied in the literature with the main reaction products cyclohexylamine, dicyclohexylamine, A-phenylcyclohexylamine, diphenylamine, ammonia, benzene, cyclohexane, cyclohexanol and cyclohexanone [1-9], The products formed depend on the catalyst used, reaction temperature, solvent and whether the reaction is performed in gas or liquid phase. For example high temperature, gas-phase aniline hydrogenation over Rh/Al203 produced cyclohexylamine and dicyclohexylamine as the main products [1],... 

Upstream oil production uses inhibitors for oil drilling operations as well as permanent production tubulars and pipelines, where two-phase and three-phase production streams are treated with filming inhibitors. The amount used ( 153 million) in production is dependent on the amount of water produced with the oil. The economics of such a system is calculated as cost per barrel of oil or water produced. This has been estimated in the lower 48 states to range from 0.02 per barrel of oil produced to 0.23 per barrel of oil produced, depending on factors such as temperature, corrosive gases present, and operating procedures. 

Continuous treatment of oil wells by inhibitors is achieved by this method. The liquid inhibitor is pumped down through the tubing into the oil producing geological formation under low pressure which acts as a chemical reserve. In oil wells, 1-2 drums of inhibitor is mixed with 10-20 bbl of water (Ibbl (British barrel) = 36 gallons), and is pumped into the well followed by pumping in over-flush fluid (50-75 bbl). The inhibitor is absorbed by the formation. It slowly escapes from the formation over a period of time to inhibit the corrosive fluids. A continuous slow release of the inhibitor from this producing formation into the corrosive fluids is the key to... 

Even in early days, oil producers applied numerous chemical com-poimds, sometimes with success, to minimize corrosion damage in the oil wells themselves and in surface handling equipment. Once amines and imidazolines came into use, corrosion inhibition in oil wells became dramatically more effective. Modem inhibitors are applied in the field, continuously or by periodic batch, at concentrations of 15 to... 

Results of the study of corrosion control by inhibitors in producing oil wells in carbon dioxide flooded fields showed imidazolines are successful in protection in CO2 brines. The inhibitor was found to be incorporated in the carbonate corrosion product layer but was still more effective if the surface film contained sulfide. Also, better results were obtained with inhibitors, such as nitrogen-phosphorus compoimds or compounds with sulfur in the organic molecules. 

---