Gazprom Neft is testing cutting-edge seismic data analysis technology for better-quality seismic imaging.* Methodological approaches under development are making it possible to obtain previously unachievable volumes of geological information, and to identify areas of irregularity (fissures) with maximum accuracy, allowing effective planning of field-development systems. Company-wide, using this new technique will improve efficiency in planning drilling operations by optimising the spacing of exploratory and production wells. More accurate forecasting of rock fracturing will result in a five-percent increase in usable fracture volumes in well drilling, by optimising angles in opening up fissures and by involving a larger volume of fractures, allowing greater volumes of initial well flows.
This new technology makes it possible to obtain the most detailed possible seismic imaging of an environment for structural-tectonic modelling, as well as additional information on the spatial distribution of reservoir irregularities — i.e., making it possible to determine where intrinsic (natural) fissures or cracks have been formed therein, and how. This is achieved through the use of breakthrough seismic attributes, their subsequent integration with geomechanics, and the creation of a mutually agreed geological-geomechanical field model. This is important in planning well spacing: depending on the task in hand, these can either be drilled where fissures are concentrated or, conversely, can bypass them. Fissures lead to a significant increase in oil inflows into a well, since they increase reservoir permeability. In some cases, however, they are so large as to risk drilling-mud loss, making further drilling impossible. Added to which, water or gas, as well as oil, can enter the well through these fissures — something which has to be taken into account in field development.
This technology has already been used at Serbia’s Turia-1 field throughout 2016 and 2017 (being developed by Gazprom Neft subsidiary NIS), under the oversight of specialists from NIS’ and Gazprom Neft’s Science and Technology Centres, with testing undertaken on the geology of fractured reservoirs in the Paleozoic sub-strata of the Pannonian Basin, Serbia. Specialists from these Science and Technology Centres have developed a unique method for interpreting the information obtained, comparing results with development data and establishing that the quality of seismic imaging is significantly improved, making it possible to clarify the structural-tectonic model in order to more accurately identify fissures within the reservoir. Testing of this new technology is currently ongoing at Gazprom Neft’s assets in Orenburg.
«The quality of geological prospecting is what drives the success of future field development. Conclusions made on the basis of interpreting seismic data form the basis for drilling and infrastructure development plans. Which is precisely why it is important to be at cutting edge of technological development in seismic surveying, and to apply the latest and highest-quality methods in its interpretation. This allows optimum accuracy in drilling wells, in order to develop new assets as effectively as possible».Mars Khasanov CEO, Gazprom Neft Science and Technology Centre
* Algorithm for ES360 full-azimuth angle domain imaging and AVAz inversion.
Seismic imaging is a procedure for mapping seismic data used in building real-image geological cross-sections.