多年来，水力压裂方法已经发生了变化，而且库存始终是运营商关心的一个问题，一些勘探与生产公司正在重返页岩区（尤其是 Eagle Ford 页岩），在可能还有一些剩余资源的油井中进行勘探。

水力压裂作业通常仅生产储层可用石油的约 10%。

自水力压裂早期以来，公司已经改进了操作的大部分方面，从用水和支撑剂装载到级数和井间距。现在，他们开始转向老式井，其中一些是几年前用更原始的方法钻探的，以挤出更多的桶。

Over the years, the hydraulic fracturing recipe has changed and with inventory always a concern for operators, some E&Ps are returning to shale plays —particularly the Eagle Ford Shale— to forage through wells that may yet have some meat on the bone.

Fracking operations typically produce only about 10% of the available oil in place from a reservoir.

Since the early days of fracking, companies have improved most aspects of operations, from water use and proppant loading to the number of stages and the spacing of wells. Now they’re turning to vintage wells, some drilled years ago with more primitive methods, to squeeze out more barrels.