Evaluation of suspension flow and particulate materials for control of fluid losses in drilling operation

Abstract

Abstract The oil and gas industries have made efforts in the development of technologies and techniques in well drilling. However, as new sources of hydrocarbons are found in reservoirs, increasingly remote and geologically complex, the industry continues to handle new challenges. A new challenge faced by drilling companies in Brazil is to combat lost circulation in limestone formations naturally fractured that is a common scenario in drilling the pre-salt wells. Combating loss by the proper use of wellbore strengthening materials (WSM) and lost circulation material (LCM) is fundamental to a successful drilling. The main objective of this work is to develop an experimental study that aims to evaluate the effectiveness of different particulate materials in combating lost circulation in fractures. An experimental apparatus was proposed to physically simulate the fluid flow in fractures of 2 mm, 5 mm and 10 mm of thickness. The length of those fractures is approximately 1.5 m. In this work we studied the fluid flow in fractures as pure water, polymers solution in water and suspension of many kinds of limestone as particulate material commonly employed as loss control materials. Those fluids were characterized with the obtention of rheology curves, density, concentration of solids, particle size distribution and particle analyzing images. We evaluated the influence of different polymers and particulate material on the rheology. We studied the fluid flow and its capability of sealing the fracture with different operating conditions such as flow rate, pump pressure, solids concentration, solid form (granules, flakes and laminar) and particle size distribution in the fluid flow. For suspensions that did not seal the fractures, we determined the pressure drop as a function of the flow rate.