Using Drill Cuttings Waste as Resource for Spud Mud

Abstract

Today oil-contaminated drill cuttings are regarded as a waste in the oil industry and have to be treated before simply depositing in an onshore facility. Thermal technology to treat contaminated drill cuttings, remove most hydrocarbons and recover the subsurface material in a dry powder form exists. Due to the similarity between subsurface rock mineralogy and conventional bentonite used in the drilling fluid industry an extended laboratory study was carried out to evaluate the possibility of spud mud development using thermo-mechanically treated drill cuttings. A total number of 28 spud mud compositions were prepared including two commonly used bentonite spud muds and tested in accordance with the API 13B-1 practices. An aging experiment was conducted as well to evaluate the stability of the designed fluids. Moreover, application of barite as a weighting material and short chain CMC polymer as a fluid loss control agent was investigated as well. As a result of the conducted experiments stable seawater-based spud mud compositions with application of xanthan gum and thermo-mechanically treated drill cuttings were developed. The designed fluids have comparable properties with the conventionally used spud muds. Depending on the composition plastic viscosity varied from 6 to 12 cP and yield stress varied from 1.53 to 5.11 Pa. The fluids were stable and capable of suspending heavy barite particles. The CMC polymer demonstrated good fluid loss control qualities. The new fluids might be cost effective in case of weighted muds and when drilling through impermeable formations. This paper shows in detail how cleaned drill cuttings can be recycled into new drilling fluid materials, which brings environmental benefits along with the economical benefits. The designed spud muds with application of drill cuttings are ready to be tested in a large-scale facility.