Performance of a New Biodegradable Ester Based Lubricant for Improving Drilling Operations with Water Based Muds

The development of new drilling technologies like extended reach drilling (ERD) or slimhole drilling and the reinforcement of environmental legislations require new adaptation of water based formulations. Good lubricating properties of the mud that would minimize any risk of differential pressure sticking of the pipe are of major impact on the efficiency of drilling operations. A biodegradable and non toxic ester based lubricating formulation has been developped that significantly reduces torque and pipe drag. Efficiency of the lubricant has been confirmed by an extensive testing under strictly controlled laboratory conditions simulating actual drilling conditions. The lubricant is very efficient on many different water based formulations, even containing high content of salts or solids, cases where classical lubricants are usually poorly efficient. The ester based lubricant is also very efficient for low solids formulations used for slimhole drilling. It is readily dispersible in water based muds and does not affect mud rheology nor filtration behavior nor any other mud property; in some cases its addition may even improve the filtrate loss reduction. Furthermore this highly efficient additive is completely biodegradable and non ecotoxic. Field tests carried out in Africa, north sea and US have largely confirmed the laboratory results presenting, for instance, a torque reduction of more than 40%.