| CPC C09K 8/36 (2013.01) [C09K 8/34 (2013.01)] | 11 Claims |

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1. An invert oil-based mud (OBM), comprising:
an oleaginous continuous phase;
an aqueous internal phase; and
5.0 to 10 wt % of an emulsifier relative to the total weight of the OBM, wherein the emulsifier is 2-dodecenyl succinic acid.
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