Estudo do escoamento de suspensão e da perda de carga em fraturas

Abstract

The oil and gas industry has made great progress in developing 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 develop technologies. To address the well drilling challenges that present security and economic risks to the long-term viability. A challenge posed by drilling companies is to combat loss of circulation in carbonate formations naturally fractured, as it is a common scenario in drilling the pre-salt wells. Combating loss, by the proper use of wellbore strengthening materials (WSM) and loss circulation materials (LCM) are fundamental to a successful drilling. This study sought to develop an experimental study that aims at evaluating different caps to combat loss of circulation in fractures. An experimental apparatus was used to simulate the fluid flow in fractures of 2 mm, 5 mm and 10 mm thick, whose length is approximately 1.5 meter in the annular 12 ¼” (311,15 mm) and 8 ½” (215.90 mm). For the characterization of fluids (suspensions and solutions) were determined rheology curves, the density, the concentration of solids, the particle size distribution and particle analyzing images. It has been the influence of the different polymers on the rheology of particle fluids. With regard to the study of fluid flow in the fracture was evaluated for different operating conditions, including flow rate, pump pressure, solids concentration of solid form (granules, flakes) and the particle size distribution in the fluid flow and some cases the sealing of the fractures. The limestone in granular form has not sealed any of the studied fractures. The materials composed of calcium carbonate in a laminar form based flakes (Soluflakes) showed greater dispersion in particle size distribution and were more effective in sealing even at low concentrations.For suspensions that did not seal the fractures, we determined the pressure drop in function in fractures of fluid flow in fractures. This methodology allows to evaluate the flow of suspensions in fractures.