圣安东尼奥的 OG Resources 通过部署其页岩 EOR 计划来满足其在 Eagle Ford 取得更好成果的需求。该公司表示，通过注气工艺，Eagle Ford 的石油产量可增加 80%。

“如果达到目标压力并且正确执行此过程，您将获得该井 100% 的增量石油。这就是经济强劲的原因，因为 IOR 生产并没有像我们习惯的那样出现延迟，”Shale IOR 首席执行官 George Grinestaff 在 Hart Energy 最近举行的 DUG Eagle Ford 会议上表示和展览。

在生产聚焦期间，Grinestaff 介绍了 EOG 的 Eagle Ford 页岩循环注气工艺从试点到全面开发的案例分析。在研究中，Grinestaff 发现，在该区域的挥发性油窗口中进行注气项目可以为操作员带来巨大的提升和最佳的气体成分。

Grinestaff 在油藏工程领域拥有 35 年的经验，他将 EOG 的成功归功于对增产过程相态的理解。

“如果你不了解相位行为，你就会出去做出不会给你带来强劲经济效益的决定，”他说。“任何人都可以制作油藏模拟模型，但很少有人制作出真正与油井行为、液体产量或成分产量相匹配的模型。”

EOG 将这些信息纳入试点，在其马丁代尔装置中开发了一个四井垫。钻探结束后，油井产量开始下降，但日产量开始达到 150 桶。EOG 在开始注气过程之前立即停止生产，为期 30 至 40 天。两年后，压缩机被拆除，油井又恢复枯竭状态。

根据试点结果，Shale IOR 设计了井产油率图表，将历史数据与模拟数据进行比较，准确匹配 IOR 效益。Grinestaff 表示，试点的历史匹配模型显示 EOG 的注入项目将产生 1.75 至 2.00 的 IOR 比率。

——这个 IOR 值为 2.0，在适当的情况下，我们可以将其提高到 3.0。这意味着恢复率提高了 300%，因此这不是一个微不足道的过程，”他说。

EOG 于 2016 年开始全面开发循环注气，其 Mitchell、Henkhaus 和 Baker Deforest 装置之间有 28 口井。根据页岩 IOR 研究，天然气增产显示出碳氢化合物气体注入的一致 IOR 响应，其中石油产量随着天然气的增加而增长。

“通过成分优化和循环操作，我们看到了巨大的提升，”他说。“我们的模拟工作表明，该流程非常强大，并在 15 年后产生了正现金流。对于一个经济周期，我们将其定为 10 年，但我们认为这些项目会持续很长时间。”

根据案例分析，EOG 在其 Max、Dullnig、Cheslyn 和 Inman 装置中启动了最新的 EOR 项目，这些项目显示出强劲的 IOR 性能。目前的项目在注气的头几年也实现了稳定生产。

Grinestaff 表示，Shale IOR 表示，Eagle Ford 挥发油窗口已经超出了试点阶段，EOG 的成功可以被其他对这一过程有合理了解的运营商复制。

“我们相信，随着油井的枯竭并接近边际价值，IOR 将在不久的将来在二叠纪或马塞勒斯等其他非常规油气田中得到同样的应用，”Shale IOR 在报告中表示。“这个过程给枯竭的油井带来了活力，而且回报时间很好，产生了强劲的经济效益。”

“但是，循环这些油井并不是一个容易的项目，我们认为您确实需要进行组合工作。如果你不这样做，你可能会错过好处，”格里内斯塔夫说。

SAN ANTONIO—EOG Resources is meeting its appetite for better results in the Eagle Ford through the deployment of its shale EOR program. The company said it is able to yield up to 80% more oil in the Eagle Ford from its gas injection process.

“If you reach your target pressure and you do this process properly, you get 100% of the incremental oil for that well. That’s why the economics are robust [because] there’s not a delay in the IOR production like we’re used to,” George Grinestaff, CEO, Shale IOR, said at Hart Energy’s recent DUG Eagle Ford Conference and Exhibition.

During the production spotlight, Grinestaff presented the case analysis of EOG’s Eagle Ford shale cyclic gas injection process from pilot to full development. In the research, Grinestaff found that conducting gas injection projects in the play’s volatile oil window rewarded the operator huge uplift with optimal gas composition.

With 35 years of experience in reservoir engineering, Grinestaff credits EOG’s success to understanding phase behavior of the stimulation process.

“If you don’t have the phase behavior understood you’re going to go out and make decisions that are not going to give you the robust economics that you can get,” he said. “Anybody can make a reservoir simulation model, but few make one that actually matches the well behavior, the liquid production or the compositional production.”

Taking this information into its pilot, EOG developed a four-well pad in its Martindale unit. After drilling, the wells started on decline, but began producing 150 barrels per day. EOG proceeded to shut-in production before starting the gas injection process, all at once, in the wells for a 30- to 40-day period. Following two years, the compressor was removed and the wells went back to depletion.

From the pilot field results, Shale IOR designed a well oil rate chart that compared historical data against simulated data, which accurately matched the IOR benefit. The history match model of the pilot, Grinestaff said, showed EOG’s injection projects would yield an IOR ratio of 1.75 to 2.00.

“This IOR ratio of 2.0, in the right situations, we can drive up to 3.0. That’s a 300% increase in recovery, so it’s not an insignificant process,” he said.

EOG began full scale development of cyclic gas injection in 2016 with 28 wells between its Mitchell, Henkhaus and Baker Deforest units. The gas stimulation showed a consistent IOR response from hydrocarbon gas injection where oil production grew as gas increased, according to Shale IOR research.

“We see a large uplift with compositional optimization and also with cycle operations,” he said. “Our simulation work shows the process is strong and producing positive cash flow after 15 years. For an economic cycle we cut it off at 10 years, but we see these projects lasting a long time.”

EOG started its most recent EOR projects in its Max, Dullnig, Cheslyn and Inman units that are showing a strong IOR performance, according to the case analysis. The current project is also seeing steady production in the first couple years of gas injection.

Shale IOR indicated that the Eagle Ford volatile oil window is beyond the pilot stage and EOG’s success could be repeated by other operators with reasonable understanding of the process, Grinestaff said.

“We believe the same application for IOR in other unconventional plays such as Permian or Marcellus will be used in the very near future as the wells deplete and approach marginal value,” Shale IOR said in the report. “The process brings life to depleted wells and the payout time is good, yielding robust economics.”

“But, it is not an easy project to cycle these wells and we think you really need to do compositional work. If you don’t, you’ll probably miss the upsides,” Grinestaff said.