Enabling a “faster, cheaper and safer” seismic survey for DNO

Northern Iraq

Arid, mountainous region with gullies and rivers

250km²

47,427 receiver locations were recorded in total over the 28 days of acquisition period.

Pseudo orthogonal survey design over~250 km²:

• Receivers: 200m line spacing, 25m receiver point interval (47, 427 stations in total)
• Source: irregular geometry with nominal 400m line spacing at 25m shot point interval. Source lines followed ridges within the complex terrain (26,153 source points acquired in total)

Vibroseis was used as the energy source for this project, with source points restricted to accessible terrain. Daily source productivity exceeded expectations. The maximum daily production achieved was >1500 shots, and the average was 930 shots per day.

Increasing receiver density on this project allowed DNO to deliver high data quality with reduced source effort. Avoiding dynamite source operations saved money and time, with vibroseis-only operations resulting in production rates at least 3x those of previous projects.

6 teams of 3 people were able to deploy sufficient nodes in the field to start source acquisition within 5 days of the first node being deployed. The active spread contained up to 19,000 nodes and was deployed within 5 days, allowing source acquisition to begin within 1 week of production activity starting.

After the recording was completed, 6 teams of 2 people retrieved the nodes in just 6 days.

In comparison to conventional seismic surveys of a similar size and complexity using cabled geophones, the client noted that the receiver deployment and retrieval crew size was more than 50% less on this survey even though the receiver density was double that of previous surveys (a 25m receiver point spacing was used for this survey vs 50m on previous cabled surveys).

The terrain was mostly made up of gullies, mountains, and rivers and required extensive pre-planning to ensure the vibroseis trucks could access lines and operate safely. To minimize any further pre-planning requirements and deployment time, it was crucial to identify receiver technology that was easy to transport and quick to deploy on foot.

An Environmental Impact Assessment (EIA) had to be completed prior to the survey being sanctioned. DNO had to specify the technology they planned to use and showcase how they would minimize environmental footprint and land disruption in the local area, and on farming operations and infrastructure.

To achieve DNO’s operational plans for drilling the next well in their licensed area it was essential to reduce the seismic project turnaround time to pinpoint the best drilling location and fast-track decision-making.

Despite theft being common in the region, only 3% of nodes were lost but at no detriment to the final image quality and no NPT to replace lost or damaged equipment.

At the time the survey was due to commence, daytime temperatures exceeded +40°C and the extreme heat was expected to impact the ability of the crew to carry and deploy equipment in the field. DNO needed a lightweight receiver solution that was easy to carry and deploy. Seasonal rains and winds were also expected towards the end of the survey, so every effort was made to complete operations before the rainy season started, due to the risk of weather standby and additional noise..

Due to the increased operational efficiency of the nodal survey, DNO were able to expedite its program and only experienced 2 days of total downtime due to weather and GNSS challenges.

22,000 STRYDE Nodes™ were prepared and readied for shipment immediately upon contract signature enabling DNO to avoid any delays to the start of seismic acquisition and comply with the overall project timeline.

High-resolution seismic data was acquired over an area of 250skm² in just 28 days, allowing DNO to speed up the acquisition program and deliver processing-ready seismic data faster than ever experienced before. DNO received a fast-track 3D image ~4weeks after the final shot, and the fast-track results were of sufficient quality to start well planning immediately.

DNO noted that the STRYDE system was very easy to use and the layout of the nodes was extremely fast-paced. Deployment was 3 times faster with STRYDE when compared to a similar sized survey using conventional cabled geophones. Source acquisition was able to start within days of the first node being deployed.

Using lightweight modern receiver technology means that fewer vehicles and crew are needed for less time in the field, resulting in less HSE risk exposure. DNO reported zero HSE incidents during the seismic operations.

The per-channel cost of STRYDE seismic systems is at least half that of any other seismic system in the world. Added to this, the operational efficiency of STRYDE systems means that project cycle time can be reduced simultaneously with running a smaller crew with fewer vehicles and reduced logistics effort, all of which contributes to a significant reduction in the overall cost to acquire the survey.

Use of STRYDE’s inobtrusive receiver technology meant there would be minimal land disruption and environmental footprint. This supported the permitting process and helped ensure the seismic survey could commence in the desired location.

Use of nodes reduced the need for line checks and eliminated technical downtime. Previous cabled system operations required time-consuming troubleshooting every day in difficult terrain to deal with theft and damage of system equipment. The customer noted that about 2 hours of productivity was gained each day through the use of nodes rather than cables by avoiding technical downtime. This time saving contributed to significant improvements in productivity and accelerated delivery of the overall seismic programme.