Amide emulsifier for high-temperature oil-based drilling fluid
Drilling fluid compositions include an emulsifier having a generic structure A, structure B, or a combination thereof. Structure A includes an amide (e.g., amic acid group) and structure B includes a cyclic imide. The emulsifier of the emulsifier system is formed by reacting a fatty oil amine (e.g., oleyl amine), with a cyclic anhydride (e.g., succinic anhydride) in the absence of diluent or in a diluent that does not react with the starting materials. The reaction takes place via application of a stepwise increase in temperature. An emulsifier based on structure A is formed when the reaction temperature is maintained at 50 to 100° C. for 1 to 3 hours. A further increase in reaction temperature (e.g., up to 200° C.) can include water elimination which results predominately in the formation of a molecule represented by structure B.
1. A wellbore fluid, comprising:
an oleaginous external phase;
a non-oleaginous internal phase; and
an emulsifier composition that includes a reaction product of i) a primary fatty amine component and ii) a capping agent selected from the group consisting of a cyclic anhydride or a diacid, wherein the reaction product comprises at least one of a first structure and a second structure, wherein the first structure includes a) a non-terminal amide group derived from an amine group of the primary fatty amine component and a carboxyl group of the capping agent and b) a terminal carboxylic acid group derived from the capping agent, and wherein the second structure includes a terminal cyclic group derived from ring closing of the non-terminal amide group and the terminal carboxylic acid group of the first structure.
2. The wellbore fluid of claim 1 , wherein the primary fatty amine component has an alkyl chain length of about 12 to 70 carbons.
3. The wellbore fluid of claim 1 , wherein the primary fatty amine component is selected from the group consisting of oleyl amine, linoleyl amine, tall oil amine, or tallow amine.
4. The wellbore fluid of claim 1 , wherein the capping agent is cyclic anhydride.
5. The wellbore fluid of claim 4 , wherein the cyclic anhydride includes one or more of maleic anhydride, succinic anhydride, alkenyl succinic anhydride, alkyl succinic anhydride, glutaric anhydride or phthalic anhydride.
6. The wellbore fluid of claim 1 , wherein the reaction product includes the Structure A formed at a temperature of about 60 to about 80° C.
7. The wellbore fluid of claim 1 , wherein the reaction product includes the first structure formed at a temperature of about 60 to about 80° C., and further includes the second structure formed at a temperature of about 100 to about 180° C.
8. The wellbore fluid of claim 1 , further comprising one or more rheology additives.
9. The wellbore fluid of claim 8 , wherein the one or more rheology additives include one or more of fatty acids, dimers, trimers, Rhecon, or hexyl carbitol series additives.
10. The wellbore fluid of claim 1 , wherein the primary fatty amine component has an amine group having nitrogen bonded to a single carbon.
11. The wellbore fluid of claim 1 , wherein the reaction product includes the first structure, wherein the non-terminal amide group is positioned between the terminal carboxylic acid group and a carbon chain in the first structure.
12. A wellbore fluid emulsifier, comprising:
a reaction product of i) a primary fatty amine component and ii) a capping agent selected from the group consisting of a cyclic anhydride or a diacid;
wherein the reaction product comprises at least one of a first structure and a second structure, wherein the first structure includes a) a non-terminal amide group derived from an amine group of the primary fatty amine component and a carboxyl group of the capping agent and b) a terminal carboxylic acid group derived from the capping agent, and wherein the second structure includes a terminal cyclic group derived from ring closing of the non-terminal amide group and the terminal carboxylic acid group of the first structure.
13. The emulsifier of claim 12 , wherein the reaction product comprises a blend of the first structure and the second structure.
14. The emulsifier of claim 13 , wherein the capping agent is succinic anhydride and the reaction product includes a molecule of the following structure:
15. The emulsifier of claim 14 , wherein the reaction product further includes a molecule of the following structure:
16. The emulsifier of claim 12 , wherein the primary fatty amine component is selected from the group consisting of oleyl amine, linoleyl amine, tall oil amine, or tallow amine.
17. The emulsifier of claim 12 , wherein the capping agent is cyclic anhydride.
18. The emulsifier of claim 12 , wherein the primary fatty amine component has an amine group having nitrogen bonded to a single carbon.
19. The emulsifier of claim 12 , wherein the reaction product includes the first structure, wherein the non-terminal amide group is positioned between the terminal carboxylic acid group and a carbon chain in the first structure.