Patent Application
20150105578
This Invention relates to the acid stimulation of oil & gas wells, and in particular to acidizing treatments and methods of using such acid fluids in treating formations having low permeability.
Using aqueous acid solutions to acidize oil & gas wells is well known. Typically, an aqueous acid solution is pumped through the well bore into the formation where it reacts with materials in the formation to increase the permeability thereof. The increased permeability brings about an increase in the flow of hydrocarbons from the formation into the well bore.
Many compositions have been proposed as corrosion inhibitors for ferrous metals in oil field applications. Many of said compositions exhibit acceptable rates of inhibition however they contain ingredients like Methanol, Acetylenic Compounds, Propargyl Alcohol, EthylOctynol, NonylPhenol, Benzyl Chloride, etc which are either toxic, flammable and/or corrosive and some also feature on the EPA's Priority Pollutants List. It would be desirable to have a corrosion inhibitor consisting of components with good HSE characteristics (ones which are Non-Toxic, Inflammable, Not-Corrosive, Biodegradable or have Short Half Lives in the environment, Non-Marine Pollutants, etc), which could be used in effective amounts and would exhibit acceptable rates of inhibition.
The following patents are representative of Corrosion Inhibitor formulations with components that exhibit poor HSE characteristics U.S. Pat. No. 3,077,454; U.S. Pat. No. 3,669,613; U.S. Pat. No. 4,493,775; U.S. Pat. No. 5,366,643; U.S. Pat. No. 5,441,929; U.S. Pat. No. 5,697,443.
The present invention is such a film forming corrosion inhibitor composition comprising:
A. Cinnamyl Nitrile
B. Other know corrosion inhibitor constituents like
C. Surfactants
D. Solvents like
Corrosion Inhibitor of the present invention exhibits “acceptable inhibition rate” when used in “effective amounts” without the use of ingredients like Methanol, Acetylenic Compounds, Propargyl Alcohol, EthylOctynol, NonylPhenol, Formaldehyde, Benzyl Chloride, Antimony, etc which are either toxic, flammable, corrosive, marine pollutants, have large half lives in the environment and/or are not biodegradable (considered to have poor HSE characteristics).
Hence Corrosion Inhibitor of the present invention exhibits “acceptable inhibition rate” when used in “effective amounts” using ingredients that have excellent HSE characteristics (are non-toxic, inflammable, not-corrosive, not marine pollutants, have short half lives in the environment and/or are biodegradable).
Acceptable Inhibition Rate is considered to be, 0.05 lbs loss in weight of the metal sample when 1 sq ft of the test metal sample in submerged in acid for a period of 24 hours, by those individuals skilled in the art of acidizing wells. Effective amounts are usually considered to be, 1 gpt (0.1% by volume or 1 gallon of formulated corrosion inhibitor per thousand gallons of acid) to 10 gpt (1% by volume or 10 gallon of formulated corrosion inhibitor per thousand gallons of Acid), by those individuals skilled in the art of acidizing wells.
The acid corrosion inhibitor formulation of the present invention includes Cinnamyl Nitrile as the active ingredient along with a number of additional components like surfactants, solvents, emulsifiers, etc and may include previously known corrosion inhibitors that have acceptable HSE characteristics like Cinnamic Aldehyde, etc.
Adding effective amounts of Cinnamyl Nitrile to other know acid corrosion inhibitor compositions improves their corrosion inhibition properties. In lab trials conducted, Cinnamyl Nitrile has been added to corrosion inhibitor formulated as taught by U.S. Pat. No. 6,068,056 and test results of the corrosion inhibitor so formulated exhibit better corrosion inhibition rates due to the presence of Cinnamyl Nitrile.
It is possible to substitute Cinnamyl Nitrile for ingredients which have poor HSE characteristics in other know acid corrosion inhibitor compositions and retain acceptable corrosion inhibition rates. In lab trials conducted, Cinnamyl Nitrile was been substituted in place of EthylOctynol as taught in U.S. Pat. No. 4,493,775; test results of the corrosion inhibitor so formulated also exhibit better corrosion inhibition rates due to the presence of Cinnamyl Nitrile.
Cinnamyl Nitrile can be synthesized in a number of ways know to people skilled in the art of organic chemistry. Precursors that will generate Cinnamyl Nitrile in situ under wellbore conditions can also be used instead of Cinnamyl Nitrile.
While Cinnamyl Nitrile is specifically named as the ingredient that improves HSE characteristics and corrosion inhibition performance; other Aromatic Nitriles are expected to accomplish the same effect.
A bottle with a cap that has an arrangement to suspend a pipe section is placed in an oil bath at the desired temperature for the desired time. Pipe section to be tested is degreased in acetone and sodium hydroxide 20% for 15 minutes each; scrubbed with a bristle brush in hot soapy water, rinsed and dried. Pipe section is weighed after drying. Pipe section is suspended in 500 ml of acid for the desired time while the bath is held at the desired test temperature. Pipe section is removed after being submerged in the acid at the end of the desired time, washed under water, scrubbed with a bristle brush, dried and weighed again to calculate loss in weight.
Time=24 hours
A bottle with a cap that has an arrangement to suspend a pipe section is placed in an oil bath at the desired temperature for the desired time. Pipe section to be tested is degreased in acetone and sodium hydroxide 20% for 15 minutes each; scrubbed with a bristle brush in hot soapy water, rinsed and dried. Pipe section is weighed after drying. Pipe section is suspended in 500 ml of acid for the desired time while the bath is held at the desired test temperature. Pipe section is removed after being submerged in the acid at the end of the desired time, washed under water, scrubbed with a bristle brush, dried and weighed again to calculate loss in weight.
Time=24 hours
100 ml Cinnamyl Nitrile, approx 90% pure is mixed with 100 ml aqueous solution of Cocoamidopropyl Betaine, approx 35% pure at room temperature on a magnetic stirrer.
100 gm Naphthylmethylquinolinium Chloride, approx 90% pure is mixed with 50 gm of an aqueous solution of Cocoamidopropyl Betaine, approx 35% pure and 50 gm Propylene Glycol, approx 99% pure at room temperature on a magnetic stirrer.
100 gm Cinnamic Aldehyde, approx 99% pure is mixed with 50 gm of an aqueous solution of Cocoamidopropyl Betaine, approx 35% pure and 50 gm Propylene Glycol, approx 99% pure at room temperature on a magnetic stirrer.
100 gm EthylOctynol, approx 95% pure is mixed with 50 gm of an aqueous solution of Cocoamidopropyl Betaine, approx 35% pure and 50 gm Propylene Glycol, approx 99% pure at room temperature on a magnetic stirrer.
A bottle with a cap that has an arrangement to suspend a pipe section is placed in an oil bath at the desired temperature for the desired time. Pipe section to be tested is degreased in acetone and sodium hydroxide 20% for 15 minutes each; scrubbed with a bristle brush in hot soapy water, rinsed and dried. Pipe section is weighed after drying. Pipe section is suspended in 500 ml of acid for the desired time while the bath is held at the desired test temperature. Pipe section is removed after being submerged in the acid at the end of the desired time, washed under water, scrubbed with a bristle brush, dried and weighed again to calculate loss in weight.
Time=24 hours
100 ml Cinnamyl Nitrile, approx 90% pure is mixed with 100 ml of Ethoxylated Sorbitan Monooleate, approx 97% pure at room temperature on a magnetic stirrer.
100 gm Naphthylmethylquinolinium Chloride, approx 90% pure is mixed with 100 ml Ethoxylated Sorbitan Monooleate, approx 97% pure and 50 gm Propylene Glycol, approx 99% pure at room temperature on a magnetic stirrer.
100 gm Cinnamic Aldehyde, approx 99% pure is mixed with 100 ml Ethoxylated Sorbitan Monooleate, approx 97% pure and 50 gm Propylene Glycol, approx 99% pure at room temperature on a magnetic stirrer.
100 gm EthylOctynol, approx 95% pure is mixed with 100 ml Ethoxylated Sorbitan Monooleate, approx 97% pure and 50 gm Propylene Glycol, approx 99% pure at room temperature on a magnetic stirrer.
