Bp Exploration Operating Company Limited

The British Petroleum Company, P.l.c.

Antony Roland Edwards

Christopher George Osborne

Simon Neil Duncum

Keith James

Simon N Duncum

A method of inhibiting or retarding formation of hydrates from water and a lower alkane, such as methane or ethane, involves adding additives which comprise (i) a corrosion inhibitor and (ii) a salt which is of formula &lsqb;R (R )XR &rsqb; Y , wherein each of R , R and R is bonded directly to X, each of R and R , which may be the same or different is an alkyl group of at least 4 carbons, X is S, NR or PR , wherein each of R and R which may be the same or different represents hydrogen or an organic group, with the proviso that at least one of R and R is an organic group of at least 4 carbons, and Y is an anion, the additives being added in an amount effective to inhibit or retard hydrate formation, to a medium susceptible to hydrate formation.

Hydrate inhibition

A hydrate inhibitor comprising a blend of an additive (i) and at least one of an additive (ii) and an additive (iii) wherein additive (i) is a polymer of an ethylenically unsaturated N-heterocyclic carbonyl compound, with 6-8 ring atoms in the heterocyclic ring, additive (ii) is a corrosion inhibitor and additive (iii) is a salt of formula (I):&lsqb;R,(R,)XR,&rsqb;,Y,1/v, I wherein each of R,, R,and R,is bonded directly to X, each of R,and R,, which may be the same or different is an alkyl group of at least 4 carbons, X is S, NR,or PR,, wherein each of R,and R,which may be the same or different represents hydrogen or an organic group, with the proviso that at least one of R,and R,is an organic group of at least 4 carbons, especially at least 5 carbons, and Y is an anion of valency v, wherein v is an integer of 1-4.

A method of inhibiting or retarding formation of hydrates from water and a lower alkane, such as methane or ethane, involves adding additives which comprise (i) a corrosion inhibitor and (ii) a salt which is of formula [R.sup.1 (R.sup.2)XR.sup.3 ].sup.+ Y.sup.-, wherein each of R.sup.1, R.sup.2 and R.sup.3 is bonded directly to X, each of R.sup.1 and R.sup.2, which may be the same or different is an alkyl group of at least 4 carbons, X is S, NR.sup.4 or PR.sup.4, wherein each of R.sup.3 and R.sup.4 which may be the same or different represents hydrogen or an organic group, with the proviso that at least one of R.sup.3 and R.sup.4 is an organic group of at least 4 carbons, and Y is an anion, the additives being added in an amount effective to inhibit or retard hydrate formation, to a medium susceptible to hydrate formation.

A method for inhibiting or retarding gas hydrate formation comprises adding a solution of a compound of formula: ##STR1## wherein R=OH, OCH.sub.3, OC.sub.2 H.sub.5, NHNH.sub.2 or H

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Surrey, United Kingdom

Antony Roland Edwards