井喷（Blowout），是一种地层中流体喷出地面或流入井内其他地层的现象，大多发生在开采石油、天然气之地方。

井喷为正常之现象，但出现井喷事故，天然气喷出后与空气摩擦，容易发生燃烧、爆炸，因此极度危险。解决方法是将密度大的重晶石粉灌到井里，以增加压力，止住井喷继续发生。此外，天然气井喷通常伴有大量的二氧化硫或硫化氢等有毒物质。

如果发生天然气井喷，从井口喷出没有立即点火，而扩散到空气中形成爆炸混合物，然后延迟点火，就会造成蒸气云爆炸，造成非常严重的伤害。

A blowout is the uncontrolled release of crude oil and/or natural gas from an oil well or gas well after pressure control systems have failed. Modern wells have blowout preventers intended to prevent such an occurrence.

Prior to the advent of pressure control equipment in the 1920s, the uncontrolled release of oil and gas from a well while drilling was common and was known as an oil gusher, gusher or wild well. An accidental spark during a blowout can lead to a catastrophic oil or gas fire.