Drilling technology for reservoir protection in tight gas reservoirs in the northern Ordos Basin

Abstract:

In the tight gas reservoirs of the northern Ordos Basin， the presence of fine pore throats， developed fractures， and strong sensitivity leads to severe formation damage caused by solid invasion and liquid phase trapping during drilling， which restricts efficient development. To resolve the conflict between reservoir protection and wellbore stability， this study conducts an in-depth analysis of the formation damage mechanisms and， consequently， develops targeted self-degradable temporary plugging agents and liquid-lock prevention agents. Based on this research， a novel low-damage reservoir protection drilling fluid system is innovatively constructed， integrating "physical particle self-degradable temporary plugging"， "interface modification for liquid-lock prevention"， and "multi-synergistic wellbore stabilization". This system is complemented by a horizontal well drilling acceleration technology. Field applications demonstrate that this technological system effectively reduces the depth of drilling fluid invasion and the extent of formation damage. It significantly improves the single-well production， with some wells achieving natural production without fraturing operation. This research provides robust engineering and technical support for the low-cost and efficient development of tight gas reservoirs in the Ordos Basin and similar tight gas reservoirs.