地震成像和再处理技术正在不断改进，世界各地的许多运营商正在对遗留数据进行再处理，以发现新的前景。

最近的后处理计划包括由 TGS 在英国北海中部大捕手区实施的一个项目。与此同时，继去年 Walker Ridge WAZ Reimaging 项目在技术和商业上取得成功之后，CGG 于 4 月启动了另一个墨西哥湾中部多客户端后处理项目“掷tagSeis Deux Reimaging”。

据 TGS 称，近年来，地震后处理的改进取得了重大进展。

“算法已经得到改进，可以减少地震图像中近似值的数量和大小，”TGS 首席顾问地球物理学家 David Brookes 告诉 Hart Energy。例如，速度模型已经从层析成像发展到全波形反演（FWI）。

TGS 特别强调了 FWI 领域的改进。

TGS 研发总监 Bin Wang 告诉 Hart Energy：“后者已从低频、仅潜水波、浅速度模型构建工具扩展到使用反射和其他波模式的更高频率、更深速度更新” 。“最近，FWI 已从速度模型构建工具扩展到基于反演的成像工具，称为 FWI 成像。”

CGG 还指出 FWI 的进步尤为重要。

“地震成像技术持续以越来越快的速度进步，尤其是过去几年在盐和全波场成像 FWI 方面取得的突破，”CGG 地下美国成像副总裁 Rongxin Huang成像业务，告诉哈特能源。“如果您的数据两年来都没有经过重新处理，那么您就看不到数据中的所有可用信息。”

然而，仍有改进的空间，参与地震成像的公司继续追求进一步的进步。

黄说：“改进仍在继续，可能比历史上任何时候都快，而且没有真正放缓的迹象。”目前正处于弹性 TLFWI [时滞 FWI] 商业应用的早期阶段，它在解析盐模型和盐下图像方面比其声学对应物要好得多，并且我们已经对我们可以从数据中提取的其他细节感到惊讶，例如油水界面和盐下断层隔室的显着改进的定义“我们面前还有很多年的弹性 TLFWI 开发，所以谁知道几年后我们会看到什么？”

TGS 认为，需要更经济实惠的弹性 FWI，并且分布式声学传感 (DAS) 噪声衰减和采集也仍需要改进，以便充分利用地震数据。

TGS 高级顾问地球物理学家 Daniel Davies 告诉 Hart Energy，其他可以改进的领域包括从稀疏数据中获取更多信息的能力、多次成像以及机器学习在地震处理中的应用。

戴维斯表示，多次波成像是地震处理的最新进展。他说，虽然多次波一度被视为不需要或不需要的信号，但它们包含有关地下的有用信息。新的处理算法使用接近原始数据作为输入，并通过将倍数视为数据中的额外源/接收器来执行反演以增强照明。他说，通过这种额外的照明，浅层和深层图像都可以得到显着改善。

TGS 表示，地震成像的某些方面仍然特别具有挑战性，可能需要进一步突破。

“复杂的盐下和玄武岩下成像仍然是一个挑战，”王说。“它受到当前采集技术限制的影响，需要更先进的采集和成像工具来克服反向散射的影响并改善这些区域的照明。”

然而，随着技术不断发展，CGG 对克服当前挑战的前景持乐观态度，但它警告说，进展将部分取决于市场状况和投资能力。

“多年来，我们经常认为挑战可能是无法克服的，但后来我们通过地震采集的创新设计和地震成像算法的突破来解决它，”CGG 地球科学执行副总裁 Peter Whiting ，告诉哈特能源。然而，服务公司将需要运营商的支持来继续投资地震采集和成像技术，以便能够继续这样做。与近期行业低迷相关的状况有可能扼杀创新，现在是扭转这一局面的时候了。”

TGS 还指出了市场状况如何影响对地震后处理的兴趣。

休斯敦 TGS 数据处理总监 Graziella Grech 告诉 Hart Energy：“在客户感兴趣的地区，后处理量有所增加，特别是在以基础设施为主导的勘探领域。” “边境地区的情况可能会有些不同。”

此外，怀廷指出，业界对地震后处理潜力的理解是影响运营商兴趣的一个因素。

“一些勘探与生产公司正在考虑对遗留数据进行更多的再处理，但总的来说，人们对通过现有最佳技术进行再处理可以释放的新信息量缺乏认识，”怀廷说。“人们仍然认为，一旦数据经过处理和成像，一切就完成了。” 没有东西会离事实很远。在真正的专家手中使用新技术进行再处理是一种既省时又经济高效的增值方式。”

Seismic imaging and reprocessing technologies are improving and a number of operators around the world are reprocessing legacy data to identify new prospects.

Recent reprocessing initiatives include one project in the Greater Catcher Area of the U.K. Central North Sea, being carried out by TGS. Meanwhile, in April, CGG kicked off another central Gulf of Mexico multiclient reprocessing project—StagSeis Deux Reimaging—after the technical and commercial success of its Walker Ridge WAZ Reimaging program last year.

According to TGS, significant advances have been made to improve seismic reprocessing in recent years.

“Algorithms have improved to reduce the number and size of approximations in seismic images,” TGS principal advising geophysicist David Brookes told Hart Energy. For example, velocity models have advanced from tomographic to full waveform inversion (FWI).

TGS highlighted the improvements in the field of FWI in particular.

“The latter has been extended from a low frequency, diving wave only, shallow velocity model building tool to higher frequency, deeper velocity updates using reflections and other wave modes,” Bin Wang, TGS director of research and development, told Hart Energy. “And more recently FWI has been extended beyond a velocity model building tool to an inversion-based imaging tool, called FWI imaging.”

CGG also cited advances in FWI as being particularly significant.

“Seismic imaging technology continues to improve at an ever-increasing rate, especially with the breakthrough in FWI for salt and full-wavefield imaging in the last few years,” Rongxin Huang, the vice president of U.S. imaging for CGG’s Subsurface Imaging business, told Hart Energy. “If you have data that hasn’t been reprocessed for two years, then you’re not seeing all the information available in the data.”

There is still room for improvement, however, and the companies involved in seismic imaging continue to pursue further advances.

"Improvement is still going on, probably faster than ever in history, and there's no real sign of that slowing down,” Huang said. “We are now in the early stages of commercial application of elastic TLFWI [time-lag FWI], which is much better at resolving salt models and subsalt images than its acoustic counterpart, and we are already surprised by the additional details we can extract from the data, such as the much-improved definition of oil-water contacts and fault compartments of subsalt reservoirs. There are many years of elastic TLFWI development in front of us, so who knows what we'll be able to see in a couple of years’ time?”

TGS believes there is a need for more affordable elastic FWI and that distributed acoustic sensing (DAS) noise attenuation and acquisition also still need to improve in order to get the most out of seismic data.

TGS senior advising geophysicist Daniel Davies told Hart Energy that other areas that could improve are the ability to get more out of sparser data, imaging with multiples and the application of machine learning to seismic processing.

According to Davies, imaging with multiples is a recent advancement in seismic processing. While multiples were once viewed as unwanted or undesirable signals, they contain useful information about the subsurface, he said. New processing algorithms use close to raw data as input and perform an inversion to enhance the illumination by thinking of the multiples as extra sources/receivers within the data. With this extra illumination, he said, both shallow and deep images can be significantly improved.

Some aspects of seismic imaging remain particularly challenging, according to TGS, and may require further breakthroughs.

“Complex subsalt and sub-basalt imaging remains a challenge,” Wang said. “It is impacted by limitations in the current acquisition technology and requires more advanced acquisition and imaging tools that can overcome the effects of backscattering and improve illumination in those areas.”

However, CGG is upbeat about the prospects of overcoming the current challenges as technology continues to evolve, though it cautions that progress will depend in part on market conditions and the ability to invest.

“Over the years, we’ve often thought that a challenge might be insurmountable, but then we resolve it with innovative designs in seismic acquisition and breakthroughs in seismic imaging algorithms,” Peter Whiting, CGG’s executive vice president of geoscience, told Hart Energy. “However, service companies will need the support of operators to continue investing in seismic acquisition and imaging technologies to be able to continue to do so. The conditions related to recent industry downturns have threatened to strangle innovation, and it is now time to reverse this.”

TGS also noted how market conditions can affect interest in seismic reprocessing.

“We have seen an increase in reprocessing in areas which have a lot of client interest, especially where there is infrastructure-led exploration,” Graziella Grech, TGS director of Houston data processing, told Hart Energy. “The situation may be a bit different in frontier areas.”

Additionally, Whiting pointed to the industry’s understanding of the potential for seismic reprocessing as being a factor that affects interest from operators.

“Some E&P companies are looking at doing more reprocessing of legacy data but, in general, there is a lack of appreciation of the amount of new information that can be unlocked by reprocessing with the best technology available,” Whiting said. “There is still a perception that once data has been processed and imaged, then that’s done. Nothing could be further from the truth. Reprocessing with new technology in the hands of real experts is a time- and cost-efficient way to increase value.”