TGS Confirms Growing Demand and New Uses for 4D

Written by TGS | Jun 1, 2024 5:00:00 AM

Ramform Vanguard is sailing towards another impressive milestone in our GeoStreamer technology story. The ongoing 4D monitor survey offshore Angola is the fiftieth such GeoStreamer survey since TGS started commercial multisensor 4D acquisition around 10 years ago.

Achieving the 50th GeoStreamer 4D milestone has also wider symbolic character in the context of the energy transition. The 50th survey is being acquired in West Africa where TGS pioneered GeoStreamer 4D broadband solutions in 2012 and contributed to energy security with high-quality production seismic since then. The impressive track record now also includes several larger seismic surveys for carbon capture and storage (CCS) projects and thus support the world’s decarbonization effort.

Increasing the Pace

TGS celebrated its 25^th GeoStreamer 4D Milestone in 2018. It had taken six years to build a track record of the first 25 GeoStreamer 4D surveys in true deep-tow multisensor mode. Over the last four years, we have added another 25 surveys, most of them in 2022. Although our 4D acquisition activity was relatively modest in 2019 and affected by the start of the pandemic in 2020, the pace has picked up significantly. In 2022, we have completed eight 4D GeoStreamer surveys, two more are ongoing, and we have another seven in our backlog. Today, 4D baseline and monitoring surveys represent the largest part of TGS’ contract seismic business.

Growing Demand and New Uses for 4D Seismic to Support Energy Transition

Geographically, the demand for towed-streamer seismic for reservoir monitoring has not really changed in recent years. Norway and the UK, Angola, Brazil, and Australia remain the key geomarkets. However, 4D tendering is increasing in other countries too. We recently acquired our first 4D baseline survey in Canada and monitor surveys in the US Gulf of Mexico and offshore Guyana.

In time-lapse (4D) seismic, measurements are repeated over the same location at regular intervals to assess changes in the subsurface. The method has traditionally been used to monitor dynamic characteristics such as fluid movement, saturation, and pressure in producing hydrocarbon reservoirs. More recently, we observe the 4D method being adopted for carbon storage reservoirs (CCS). In fact, two of our 2022 acquisition projects are 4D baselines over future CO2 storage sites: Northern Endurance 4D baseline (UK) and an equivalent project over the Northern Lights site (Norway). We also acquired a dual-purpose 4D monitoring survey in the Barents Sea this year.

TGS 4D acquisition technology is state-of-the-art for the seismic industry. With multisensor GeoStreamer and advanced source-steering standard technologies across our entire active Ramform fleet, we are well-equipped to acquire broadband surveys with the highest repeatability possible. Our engineers are methodically upgrading our source-steering capabilities fleet-wide, from traditional single and dual-source configurations to more advanced multi-source and wide-tow multi-source solutions.

Experience shows that our clients rarely change their technical specifications for the acquisition of monitoring projects compared to the previous snapshot on the same reservoir. They are risk-averse when acquiring seismic over their producing fields. New technology is typically introduced with 4D baseline surveys. Thus, it is only now that we are seeing multi-source solutions required by energy companies for their 4D baseline surveys. In the UK this spring, the Northern Endurance (2022) program used a wide-tow quad source, while 2021 and 2022 surveys offshore Canada on Cambriol, and offshore Norway for the Northern Lights, employed a triple source. We can expect this to be the standard also for future monitor surveys on these fields.

4D for the Future

The energy industry is now bound by dual imperatives of energy security through the continued supply of hydrocarbon resources and a requirement to deliver an energy transition to net-zero. GeoStreamer 4D seismic is a concrete example of how advanced marine subsurface knowledge is supporting our evolving energy needs by both enabling the industry to optimize its production of current resources and monitoring the security of carbon storage sites to help neutralize industrial emissions.

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