Invert emulsions can be used in oil and gas operations. A fluid loss control additive (FLCA) is a component of the fluid that can be utilized to control or minimize fluid loss into a subterranean formation. The FLCA can be a chemically modified vegetable oil that is biodegradable. Vegetable oils having some or all of the functional groups sulfonated can be used as FLCA. A water-soluble salt that has been dissolved in the discontinuous phase of the invert emulsion can combine with the FLCA to form a wax-like, solid mass.