关键词: 致密砂岩, 天然气, 地层损害, 裂缝, 钻井, 完井

Abstract: Tight gas sandstone reservoirs in western Sichuan Basin are characterized with low energy, complex in macro- and micro-structures, and extreme sensitivity to environmental varia-tions. Being congenitally deficient and liable to impairments,the damages of these reservoirs are very difficult to remove com-pletely. With the above considerations, this work initiated from effective protection of natural fractures during drilling and com-pletion. In the light of temporary shielding principles, a techni-cal system of drilling - completion - stimulation for vertical wells, accompanied by methods of predicting fracture parame-ters close to bore-hole, and by core lab evaluations on sensitiv-
ity and working fluids damage, has been formed. The practices contribute an insight into the strategy that damage control and reservoir stimulation can be integrated for gas production from these reservoirs. Based on the discussion on technical, economi-cal and environmental situations, this paper suggests that new and improved technology should be developed in order to cope
with more complicated geologic situations such as deep tight gas reservoirs and abnormally low pressure gas reservoirs. It is also pointed out that environmental protection should be an especial concern in the research and application of formation damage control technology in drilling and completion operations.

Key words: tight sandstone, natural gas, formation dam-age, fracture, drilling, well completion