Oman, known for its vast reserves of oil and gas, has embarked on a transformative journey in the realm of seismic exploration. The adoption of point receiver nodal technology, a cableless seismic acquisition system, has emerged as a game-changer, revolutionizing the way oil and gas exploration is conducted in the country. This cutting-edge technology has not only overcome the challenges posed by Oman's unique geological and environmental conditions but has also unleashed new possibilities for unlocking the country's untapped hydrocarbon potential.
In the past, traditional cabled telemetry data acquisition systems with geophone arrays were the primary means of seismic data collection in Oman. However, the introduction of single-sensor nodal technology and its vast use in the country has sparked a paradigm shift, bringing numerous benefits and enhancing the efficiency and accuracy of exploration activities whilst reducing costs.
How Oman is benefiting from nodal technology
One of the key advantages of nodal technology in Oman's rugged terrain lies in its ease of deployment. The desert landscapes and mountainous regions that characterize Oman often present formidable challenges for traditional cabled systems. Nodal technology’s cable-free nature enables rapid and flexible deployment, eliminating the labour-intensive and time-consuming process of laying cables and managing their notoriously high failure rates across difficult terrains. This has significantly expedited exploration operations and opened access to remote and inaccessible areas.
It has been proven that point receiver nodal technology excels in delivering enhanced data quality, this was recently demonstrated in Q4 of 2022 when there were over 240,000 STRYDE Nodes™ (the most compact and cost-effective nodes available on the market today) being used simultaneously to acquire high-resolution data for three different oil and gas operators across Oman.
The individual nodes, strategically placed across the exploration area, capture seismic data with improved resolution and fidelity. The elimination of long cables removes the potential for noise interference, resulting in cleaner and more reliable seismic recordings. This heightened data quality empowers geoscientists and engineers to make better-informed decisions regarding reservoir mapping, drilling strategies, and production optimization.
The coverage and sampling density achieved by agile nodal technology has improved subsurface imaging exponentially. Enabled by its reduced price point, operators can now afford to densely deploy technology like STRYDE Nodes™ that captures a much higher volume of seismic data, facilitating detailed subsurface imaging and a comprehensive understanding of Oman's complex geological structures.
The world’s largest nodal seismic survey in Oman: a case study
In a ground-breaking endeavour, seismic contractor, African Geophysical Services LLC (AGS), is currently deploying a staggering 165,000 STRYDE Nodes™ for the largest nodal seismic survey ever conducted worldwide. This ambitious 3D seismic survey, spanning over 29,219 sq. km of rugged desert terrain, is being commissioned by CCED for exploration of onshore blocks 3 and 4 in Oman.
This point receiver nodal technology approach provides multiple benefits to CCED, by cutting down on data acquisition costs, minimizing HSE footprints in the field (less manual handling, reducing vehicle count from 160 to 40, and reducing field crew size from 600 to 220 people), and expanded land access in the sabkha-dune environment, all to acquire high quality, operationally efficient, high density, point receiver geometries providing increased spatial sampling density, with no compromise to data quality outcomes.
Survey operational efficiencies
In a remarkable display of efficiency, the deployment of nodes took place on foot, utilizing small, agile vehicles to transport them between receiver points. The nodes were positioned in a precise manner, with a spacing of 10 meters along each line. A crew member operated a compact pickup truck equipped with a navigation system that housed the survey plan and a GPS antenna mounted on the vehicle. Simultaneously, another crew member walked alongside, planting the nodes at each receiver station using a small, spiked tool to dig a hole for the node.
This streamlined approach yielded impressive results with several two-person crews deploying and retrieving an astounding 10,000 nodes during a single 12-hour shift. For this project, the crew size was significantly reduced to just 220 people, representing a 63% decrease in crew size compared to the number of personnel required for deploying cabled geophones on a survey of a similar scale.
With the node’s capacity to autonomously record seismic data continuously for 28 days in the field, and the receiver system’s ability to harvest data from up to 17,000 nodes per day, the technology’s capabilities played a pivotal role in fast-tracking the survey operations. Leveraging this advantage, AGS swiftly transitioned from a 12-hour shift to a round-the-clock 24-hour shift soon after the survey's initiation.
The elimination of cables and connectors brought about a substantial reduction in potential failure points within the receiver technology. This translated to significant benefits for AGS, who were able to enjoy uninterrupted operations without downtime caused by equipment failures. Moreover, the removal of time-consuming troubleshooting and maintenance tasks, such as checking connections and fixing line breaks, became obsolete. This streamlined approach not only saved valuable time but also reduced costs during the seismic acquisition process, allowing AGS to allocate resources more efficiently and maximize productivity.
Logistics and cost savings
With a smaller node comes reduced equipment weight, and a reduced crew size. This reduction translates to a decreased need for heavy vehicles, special driving permits, accommodations, catering services, and personnel overall, as well as the overall HSE footprint and exposure to risk.
The low price point of the node itself, combined with the savings in logistics and survey costs, leads to a substantial reduction in the overall price point of a seismic survey utilizing STRYDE Nodes™. This cost-effectiveness empowers companies to access high-quality seismic data at a more affordable price, making large-scale, high-density seismic surveys using STRYDE Nodes™ a financially viable option.
Seismic data quality assurance
The data volume acquired from 10,000 nodes was averaging 25 terabytes of seismic data per day and it was imperative to assure the data acquired was accurate and of high quality. AGS utilized STRYDE SurveyQC and STRYDE SeismicQC software to monitor the reliability and quality of the seismic metadata acquired each day to produce accurate seismic data tapes (a physical storage medium used to store seismic data) that are used by seismic data processing centers to create the seismic image.
Given that the STRYDE Node™ operates as a blind recording system without real-time data visualization, STRYDE SurveyQC was instrumental in providing key insights into node deployment and retrieval position quality and operational efficiency statistics. It facilitated the assessment of critical factors such as deployed node position including elevation, recording time, sample rate, node battery level, node activation confirmation, and more. By leveraging SurveyQC, AGS gained a comprehensive understanding of the operational aspects associated with node deployment and retrieval, ensuring accurate and precise data acquisition without the need for complex radio telemetry technology.
During data harvesting, predetermined QC algorithms monitor the recorded seismic data from each node. Some of the values monitored are DC offset, signal clipping, and signal zero crossings. If there are any anomalies in the seismic data that fall outside these predetermined levels, the node is flagged for further investigation and testing to determine the cause of the anomaly.
Complementing this QC system, STRYDE SeismicQC provided a powerful tool that offered AGS a high-level view of the seismic data quality without requiring extensive data processing. SeismicQC allows viewing of the seismic data (both “Raw” data and “Shot” or “Receiver Gather” data) including seismic data attributes, including temperature, battery voltage, signal amplitude RMS values, dominant frequency, deployed vs node GPS position, in addition to other relevant information. These values can be produced in tabular form, or they can be displayed in the “Map” view. This allowed for a quick and efficient assessment of the overall general quality of the acquired seismic data.
By leveraging these monitoring systems and the high-reliability statistics of the node, AGS safeguarded the integrity of the seismic data during the acquisition and reported >99.9 % of node data had been successfully harvested.
Summary
Oman's embrace of nodal technology has unleashed a new era in oil and gas exploration. By surmounting the challenges posed by its unique geological and environmental conditions, nodal technology has paved the way for efficient, accurate, and environmentally conscious seismic data acquisition. The transformative impact of this cableless seismic acquisition system extends beyond technological advancements; it is driving Oman's pursuit of unlocking its untapped hydrocarbon potential and shaping the future of the country's energy landscape.
