Formate Derivatives Application in Drilling Fluid Engineering

Appropriate design of drilling fluid can dramatically affect the performance of drilling operation. In most of Iranian oil fields, Oil base muds are used for drilling in sensitive shale layers and reservoir section but these muds cause a serious problem, Environmental pollution. Formate brine can be appropriate drilling fluid in over balanced drilling operation that reduces the formation damage and environmental pollutions. Formate brines (sodium, potassium and cesium) primarily introduced as suitable completion fluids but applying in drilling show many advantages such as Low solid content, reduction of formation damages and frictional pressure losses in drilling operation, excellent HSE profiles, good shale stabilizers. In addition, their unique capability of stabilizing polymers at high temperatures made them more temperature resistant than any other polymer based drilling fluids.In this study our purpose was to design proper drilling fluid with potassium formate brines and some additives for different situation of the drilling operation having weight of 68 to 90 pcf. The rheological properties of formate brine can be easily controlled by polymers and the concentration of formate in the solution just affects the density. Effects of formate concentration and concentration of each additive on the rheological properties, density, thermal stability and API fluid losses of each designed fluids have been studied.It was observed that designed drilling fluids with potassium formate brine have excellent shale inhibition, thermal stability and high resistance to contamination and pH change. Finding an easier method of recycling of formate brine as a way of reducing the cost of these drilling fluids was another part of our study. At the end, we can easily design drilling fluid by formate brine with desired density and rheological properties that has no environmental pollution.

Keywords:

Formate Brines , Drill-In Fluids , Non-Damaging Solid Free Fluids