Trailblazing onshore oil and gas exploration in Ukraine

CELINA GIERSZ, STRYDE 

With some of Europe’s largest hydrocarbon reserves, Ukraine’s energy sector plays a vital role in maintaining both national and global energy security. As the global demand for energy increases amid ongoing conflict, advancing new oil and gas exploration projects and reassessing existing fields is essential to strengthening domestic production, stabilizing supply chains and reducing dependency on external sources. 

By adopting modern exploration techniques, Ukraine can significantly enhance its energy independence and contribute to regional energy stability. 

Recent advancements in seismic data collection have made it possible to rapidly generate detailed subsurface images, which are critical for informed decision-making related to well placement for oil and gas exploration and development. Earlier this year, DTEK Oil & Gas—Ukraine’s largest private energy operator—conducted the country’s first nodal high-density seismic survey at the challenging Runovshchynska salt dome in the Poltava region, Fig. 1. This survey utilized the latest in seismic acquisition technology and solutions to deliver faster, higher-resolution subsurface data required to guide exploration efforts. 

Fig. 1. DTEK seismic survey operations in Ukraine.

PROJECT OBJECTIVES AND APPROACH 

Legacy seismic data from Runovshchynska field revealed direct hydrocarbon indicators (DHIs), which supported successful past drilling campaigns. However, geologist analysis and decision-making for new development opportunities were hampered by the data’s poor resolution, particularly in the shallow sections where new discoveries could be made. Previous reprocessing efforts using the Common Reflection Surface (CRS) method improved the results, but challenges persisted, due to limited trace density and image resolution. 

The new 2024 survey was commissioned by DTEK to enhance the seismic image and attributes to provide a clearer understanding of the subsurface potential and identify additional drilling targets within the field. 

THE NEED FOR SPEED 

Commissioned during an active and tightly scheduled drilling program, DTEK urgently needed high-density seismic data to guide their drilling operations and minimize rig downtime. This meant that the entire workflow—including planning, acquisition, processing and interpretation—required optimization for rapid turnaround. 

Conventional land seismic acquisition is typically a lengthy process, due to the inherent logistical onshore field challenges and vast data volumes generated by modern high-density surveys, which require substantial computational resources for processing. Complex steps, such as noise removal, velocity model building and advanced imaging techniques like pre-stack time and depth migration, further extend the timeline, due to the iterative nature of these processes. 

To meet the required trace density, within a tight timeline, STRYDE’s autonomous nodes were chosen to acquire the seismic data. These lightweight, compact nodes (weighing in at just 150 grams, and only 13 cm tall by 4 cm wide) enabled rapid deployment with low HSE risk exposure, fewer personnel and reduced community impact, streamlining local acceptance, permitting and accelerating access to the critical subsurface data. 

To further accelerate the delivery of decision-ready seismic images, DTEK employed STRYDE Lens,™ an advanced in-field processing on-the-edge solution, Fig. 2. Remotely accessed by STRYDE's land data processing experts in London, UK, while the acquisition was ongoing, this approach proved to enable a record-breaking turnaround time for interpretation-ready seismic data and actionable results.  

Fig. 2. On the left, STRYDE's miniature, lightweight autonomous nodes and on the right, the acquisition system that transforms into a processing environment for STRYDE Lens™ processing to be delivered.

FIELD OPERATIONS AND SURVEY DESIGN 

The Runovshchynska salt dome, in the Dnieper-Donets basin, is a geologically complex area influenced by Devonian salt movement and Jurassic faulting, which required a more sophisticated solution for accurate imaging. The 2024 survey had to be geared towards a higher-resolution seismic image, therefore a high-trace density approach was required. This involved deploying 30,000 STRYDE Nodes™ across an 11-km² area, utilizing a mixed-source approach that combined vibroseis and dynamite to generate seismic waves into the earth. The survey employed an orthogonal design specifically optimized for imaging of shallower targets. 

Historically, onshore seismic survey efficiency and data quality have been limited by outdated technologies, such as cumbersome cabled geophones or expensive and heavy nodal devices, which restricted the number of sensors that could be deployed on a survey and reduced data resolution. 

The use of STRYDE’s lower-cost nodes on this survey enabled affordable, high-density nodal acquisition and delivered four times the trace density of the legacy survey acquired in this field, resulting in superior image quality. 

The successful execution of field operations, with zero health, safety or environmental incidents, further highlighted the system’s efficiencies, which allowed for rapid deployment and minimized surface disruption. A total of 50% less people were required for the project, compared to conventional surveys of a similar scale, using cabled equipment, previously completed by DTEK. 

The orthogonal design had 5-m inline sampling and 20-m crossline sampling, prioritizing inline sampling for Rayleigh wave attenuation and operational simplicity. 

HIGH-END IN-FIELD IMAGE RECONSTRUCTION  

The use of STRYDE Lens™ enabled the land seismic data processors to begin their intricate work on the workflow while the seismic data were still being acquired, eliminating delays accrued from data transfer operations and removing the need to export data out of the country. 

STRYDE Lens™ offers a first-of-its-kind, groundbreaking approach to land seismic data processing by temporarily converting STRYDE’s acquisition hardware into a processing environment. 

Installed directly onto the seismic acquisition system, STRYDE Lens™ gave STRYDE’s experts remote access to begin analysis before the survey was even complete. This early start allowed the processing team to test and develop optimized sequences tailored to the incoming data in real time. 

Pre-stack time migration (pre-STM) was run after each key milestone to assess the value of the time and effort spent on each of these processing stages. In this case, migration was conducted as a quality control tool, rather than an end-product activity. 

STRYDE Lens™ processing included most conventional steps required in land processing, including refraction tomography, several passes of linear noise attenuation, and random noise attenuation. However, testing was limited to the most impactful step in the sequence, focusing on ensuring that the kinematics, statics and velocity were as optimal as time allowed, while preserving the resolution of the data. 

This resulted in a preliminary pre-STM volume being ready for feedback and interpretation just one week after the final seismic shot was taken, with the final seismic image being issued two weeks later—a mere three weeks after the acquisition had concluded. 

Due to the structural complexity of the area, advanced processing techniques, such as transverse tilted isotropy (TTI) anisotropic pre-stack depth migration and fault-constrained tomographic velocity model building, were conducted to accurately delineate faults and structural features and further refine drilling strategies and well-track designs. 

This processing exercise was run in parallel with the Lens™ processing by another processing firm, took four months to complete, and was of comparable quality to the image the STRYDE processors delivered, Fig. 3. 

Fig. 3. Two compatible and complementary seismic products: on the left is the STRYDE image, and on the right is the conventional processed image.

This STRYDE Lens™, processing on-the-edge solution allowed early insights into the subsurface data and enabled interpreters to quickly assess structural data. This enabled the appraisal of well locations as early as possible, allowing the locations to be prepared ahead of drilling, which is a typically lengthy process, taking around four to eight weeks to complete ahead of a two-week drilling operation. 

This approach significantly reduced the data processing costs and shortened the exploration and drilling timeline, with the entire process—from the first shot to a fully interpretable migrated volume—completed in under six weeks. The insights from the conventional seismic image did not alter the decisions made related to drilling locations and well placement, further highlighting the value of the STRYDE Lens™ solution. 

This achievement sets a new record for an 11-km² high-density 3D survey, consisting of around 13 million traces, which produced a high-quality, detailed seismic image that can be leveraged to drive decisions and accelerate the exploration program. 

CONCLUSION 

The successful deployment of high-density nodal acquisition and advanced in-field processing at the Runovshchynska salt dome demonstrates how modern seismic technologies can significantly enhance subsurface imaging, streamline decision-making, and reduce exploration costs and timelines. 

The seismic image delivered by STRYDE Lens™ matched the quality of conventional methods while producing nearly six times faster. This allowed DTEK to promptly identify optimal well locations, relocate drilling equipment efficiently, and minimize rig downtime, ultimately avoiding unnecessary costs. 

By integrating acquisition and processing into a near-simultaneous workflow, this project sets a new standard for efficiency and precision in onshore exploration. It not only provides crucial insights into complex geological formations but also supports Ukraine’s path toward energy independence. 

Through the use of these cutting-edge solutions, DTEK is pioneering more effective resource exploration and development in challenging environments. 

CELINA GIERSZ is a senior geophysicist and energy transition enthusiast who specializes in onshore seismic data processing and imaging, including in-depth understanding of seismic acquisition. After obtaining a master’s in Applied Geophysics from the AGH University of Science and Technology in Poland, Ms. Giersz developed her technical expertise in the leading processing centers in Europe. At STRYDE, the onshore seismic acquisition experts, she has helped to build the processing team and to transform seismic data processing as it is known today. She leads teams of experts and manages projects for the oil and gas, CCUS, and geothermal industries.