钻井过程中保护低渗特低渗油气层的必要性、重要性与发展趋势

钻井过程中钻井液对低渗特低渗油气层的损害程度通常较中、高渗油气层大得多，但多年来部分人认为，需压裂投产的低渗特低渗油气藏，因压裂可解除油气层损害而勿需在钻井过程中采取保护油气层措施，因而对油气井产量和经济效益带来不利影响。阐述了低渗特低渗油气层损害机理的特殊性以及损害程度的严重性；依据现场实际产量数据，充分说明了钻井过程中采用效果优良的保护油气层钻井液技术有助于大幅度提高压裂后单井日产量；结合国际趋势和中国油气工业发展战略需求，阐述了将来的发展方向和趋势。不仅对提高保护油气层效果、单井产量以及油田总体经济效益具有适用价值，而且对钻井液技术的发展和中国模式“页岩革命”的建立也具有一定指导意义。 

Protecting the Low Permeability and Ultra-low Permeability Pay Zones During Drilling: Necessity,Importance and Developing Tendency

In drilling operation, damage of drilling fluids to reservoir formations with low or ultra-low permeability is higher than the damage of the drilling fluids to reservoir formations with medium or high permeability. Some reservoir specialists have long thought that low- or ultra-low permeability reservoirs that need to be fractured before being put into production do not need reservoir protection measures during drilling operation because fracturing job can eliminate the negative effect of drilling fluids to the reservoir formations. This opinion has badly affected the productivity of oil and gas wells. This paper explains the particularity of the damage mechanisms of low- and ultra-low permeability reservoirs and the severity of the damage. It proves that, using the field production data, excellent reservoir protection drilling fluid technology is helpful to the great enhancement of the daily production rate of a well after being fractured. This paper also elaborates the development direction and trend of reservoir protection based on the international trend and the strategic requirements of the development of China's oil and gas industry. The ideas described in this paper are of not only applicable value to the enhancement of reservoir protection efficiency, the daily production rate of a single well and the overall economic benefit of a whole oilfield, they also have certain guiding significance to the development of drilling fluid technology and the establishment of Chinese-style “shale-gas revolution”.