关键词: 碳酸盐岩裂缝性储层, 钻井液, 不锈钢缝板岩心, 裂缝宽度, 储层损害, 评价方法

Abstract: A series of simulated fractured core samples made of stainless steel with a given width of fracture were used to evaluate the damage of drilling fluid to fractured carbonate reservoirs in laboratory.The width of artificial fracture was estimated by virtue of the image well log information.The relative error of the width of tested core with artificial fractures decreased to 1%.A series of tests for reservoir damage were conducted by using the simulated stainless steel core samples flushed with different drilling fluids such as the sulfonate-polymer drilling fluid and the solid-free drilling fluid with or without ideal packing bridging materials.On the basis of experimental results using this kind of simulated core,a novel approach to control the damage of fractured carbonate reservoirs was presented.The experimental results show that the effective temporary plugging ring on the end face of the simulated core sample can be observed clearly and the simulated stainless steel fractured cores make it possible to visualize the solid and filtrate invasion.The new evaluation method could be used to measure the feasibility of the ideal-packing theory for the fractured reservoir,and it can also be applied to evaluate the sealing effectiveness by adding the temporary sealing particles in the drilling fluid.

Key words: fractured carbonate reservoirs, drilling fluid, simulated stainless steel fractured core, fracture width, reservoir damage, evaluation method