1. n. 
A method for recovering additional oil beyond fluid expansion, rock compressibility, gravitational drainage, pressure decline and natural waterdrive or gasdrive. This term is used in both a restricted sense and a more general sense. In its restricted sense, it is a process, such as waterflooding or gasflooding, that adds energy to a reservoir to stimulate oil production and increase recovery factor. In its more general sense, it is any activity that increases oil production and increases the recovery factor. This sense can also include, for example, enhanced oil recovery methods, infill drilling, hydraulic fracturing, and drilling horizontal and multilateral wells.