Abstract: In the depleted and low-pressure reservoirs, it is easy to be encountered with such problems as fluid total loss,differential pipe sticking and reservoir damage during conventional drilling operations, and even with contradiction between wellbore stability and reservoir protection. In view of the above problems, a detailed study on the technical status and applications for domestic and foreign aerated underbalanced drilling technology with annulus injection was conducted. Such technical problems as severe loss, differential stuck pipe and low drilling rate can be effectively solved with the aerated drilling technology with annulus injection, and precise directional drilling of horizontal wells can be achieved by using conventional drilling fluid pulse MWD /LWD, which meanwhile can protect the reservoir and increase single well production. In mature fields, by combining aerated drilling and managed pressure drilling, the aerated drilling technology with annulus nitrogen injection has been successfully performed in sulfur-bearing, fractured and depleted low pressure high temperature reservoirs, which not only protects the reservoir, but also avoids reservoir leakage and meets the requirements of well control. Field application shows that the aerated drilling technology with annulus nitrogen injection can not only protect reservoirs, but also reduce downhole incidents and drilling cost, having a wide application prospect in the drilling of low-pressure, fractured and unstable reservoirs and helping to solve the technical challenges on the efficient development for low pressure depleted reservoirs, providing reference significance for the development of managed pressure drilling technology for horizontal wells in low pressure depleted reservoirs in China.

Key words: low pressure reservoir, fractured reservoir, annulus nitrogen injection, underbalanced, MPD, concentric
casing, casing-tie back

摘要： 衰竭、低压储层钻进时易出现钻井液漏失、压差卡钻及储层伤害等问题，甚至还存在井壁稳定与储层保护的矛盾。文章针对上述问题调研了国内外强化充气钻井技术的发展现状及应用情况。强化充气钻井技术可有效解决钻井过程中的恶性井漏、压差卡钻及钻井速度慢等技术难题；也可结合钻井液脉冲实现水平井定向钻井，在精确定向作业的同时保护油气藏，提高单井产量；还可将充气钻井工艺与控压钻井技术相结合，利用环空充氮气强化充气钻井技术钻含硫、裂缝性和衰竭性低压高温油气藏，既保护储层，又避免储层井漏，满足井控要求。现场应用表明，强化充气钻井技术不仅有利于保护储层，且能减少井下复杂与钻井成本，在低压、破碎、易失稳的储层钻井中具有广泛的应用前景，有助于解决低压衰竭储层高效开发面临的技术难题，为国内低压衰竭储层水平井控压钻井技术发展提供借鉴与支持。

关键词: 低压储层, 裂缝性油气藏, 强化充气, 欠平衡, 控压钻井, 同心管, 套管回接