News Column

Patent Application Titled "Method of Using Dithiazines and Derivatives Thereof in the Treatment of Wells" Published Online

July 15, 2014

By a News Reporter-Staff News Editor at Life Science Weekly -- According to news reporting originating from Washington, D.C., by NewsRx journalists, a patent application by the inventor Taylor, Grahame Nigel (Houston, TX), filed on December 24, 2012, was made available online on July 3, 2014 (see also Patents).

No assignee for this patent application has been made.

Reporters obtained the following quote from the background information supplied by the inventors: "During the production life of an oil or gas well, the production zone within the well is typically subjected to numerous treatments. Corrosion of metallic surfaces, such as downhole tubulars, during such treatments is not uncommon and is evidenced by surface pitting, localized corrosion and loss of metal. Metallic surfaces subject to such corrosion are carbon steels, ferritic alloy steels, and high alloy steels including chrome steels, duplex steels, stainless steels, martensitic alloy steels, austenitic stainless steels, precipitation-hardened stainless steels and high nickel content steels.

"Further, aqueous fluids, such as those used in drilling and completion, have a high salt content which causes corrosion. Gases, such as carbon dioxide and hydrogen sulfide, also generate highly acidic environments to which metallic surfaces become exposed. For instance, corrosion effects from brine and hydrogen sulfide are seen in flow lines during the processing of gas streams. The presence of methanol, often added to such streams to prevent the formation of undesirable hydrates, further often increases the corrosion tendencies of metallic surfaces.

"Further, naturally occurring and synthetic gases are often conditioned by treatment with absorbing acidic gases, carbon dioxide, hydrogen sulfide and hydrogen cyanide. Degradation of the absorbent and acidic components as well as the generation of by-products (from reaction of the acidic components with the absorbent) results in corrosion of metallic surfaces.

"The use of corrosion inhibitors during well treatments to inhibit the rate of corrosion on metal components and to protect wellbore tubular goods is well known. Commercial corrosion inhibitors are usually reaction mixtures or blends that contain at least one component selected from nitrogenous compounds, such as amines, acetylenic alcohols, mutual solvents and/or alcohols, surfactants, heavy oil derivatives and inorganic and/or organic metal salts.

"Many conventional corrosion inhibitors used to reduce the rate of acid attack on metallic surfaces and to protect the tubular goods of the wellbore are becoming unacceptable in oilfield treatment processes. For instance, many conventional corrosion inhibitors have become unacceptable due to environmental protections measures that have been undertaken. In some instances, such as in stimulation processes requiring strong acids, high temperatures, long duration jobs and/or special alloys, the cost of corrosion inhibitors may be so high that it becomes a significant portion of total costs.

"Efforts have been undertaken to find alternative corrosion inhibitors which are cost effective and which are capable of controlling, reducing or inhibiting corrosion."

In addition to obtaining background information on this patent application, NewsRx editors also obtained the inventor's summary information for this patent application: "Corrosion of metallic tubulars in a well may be inhibited from forming by introducing into the well a dithiazine or dithiazine derivative of the structural formulae (I)-(V):


"wherein R is selected from the group consisting of a C.sub.1 to C.sub.12 saturated or unsaturated hydrocarbyl group or a C.sub.1 to C.sub.10 .omega.-hydroxy saturated or unsaturated hydrocarbyl group; R.sup.1 is selected from the group consisting of a C.sub.1-C.sub.24 straight or branched chain alkyl group or a C.sub.1-C.sub.24 arylalkyl group; R.sup.2 is a straight or branched alkylene group; R.sup.14 is a C.sub.1-C.sub.24 straight chain or branched alkyl group; or a C.sub.6-C.sub.24 aryl or arylalkyl group; R.sup.15 is a C.sub.1-C.sub.6 alkyl or a C.sub.6-C.sub.30 aryl or alkylaryl group; and X is chlorine, bromine or iodine.

"The compounds of formula (II), (III) and (V) are quaternized derivatives of the dithiazine of formula (I) and (IV).

"The dithiazine of structure (I) may be isolated from a whole spent fluid (WSF) formed by reaction of hydrogen sulfide and a triazine, such as a triazine of formula (VI):


"wherein R is defined above in a hydrogen sulfide scavenger gas scrubbing operation. Alternatively, the whole spent fluid containing the dithiazine of structure (I) may be introduced into the well without isolation of the dithiazine.

"Synergistic effects on inhibition of corrosion have further been noted when the dithiazine or dithiazine derivatives of formulae (I)-(V) are formulated with at least one corrosion inhibitor component selected from alkyl, alkylaryl or arylamine quaternary salts; mono or polycyclic aromatic amine salts; imidazoline derivatives; a mono-, di- or trialkyl or alkylaryl or arylalkyl phosphate ester; a monomeric or oligomeric fatty acid or salt; an alkyl or alkenyl substituted pyridinium; a polyamine amide; a polyhydroxy or alkoxylated amine or amide; a pyrazine derivative or a mercaptocarboxylic acid. Synergistic effects have further been noted when WSF is combined with a corrosion inhibiting formulation containing any one or more of these corrosion inhibitor components.


"In order to more fully understand the drawings referred to in the detailed description of the present invention, a brief description of the drawings is presented, in which:

"FIGS. 1-7 demonstrate the effectiveness as whole spent fluids (WSF), formulated with additives defined herein.

"FIGS. 8-12 demonstrate the effectiveness of quaternized reaction products of dithiazine compared to non-quaternized dithiazines."

For more information, see this patent application: Taylor, Grahame Nigel. Method of Using Dithiazines and Derivatives Thereof in the Treatment of Wells. Filed December 24, 2012 and posted July 3, 2014. Patent URL:

Keywords for this news article include: Gases, Patents, Elements, Chemistry, Carbon Dioxide, Hydrogen Sulfide, Sulfur Compounds, Inorganic Chemicals, Noncarboxylic Acids.

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Source: Life Science Weekly

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