A biodegradable wellbore fluid with an oleaginous phase including a linear paraffin having 11-18 carbon atoms, a non-oleaginous phase, an emulsifying agent and optionally a weighting agent. Use of the fluid while drilling allows bio-remediation of drill cuttings using land spreading, bioreactors, conventional composting or vermiculture composting. The resulting product, especially when vermicomposed, is potentially useful as a soil amendment or plant fertilizer material.