№ 2 (February 2009)
Gazpromneft’s 3D Sleuths Find New Oil in Tapped Out Fields
In recent years the quality of processing and interpretation of 3D seismic survey data has moved to a new level due to new technologies, software and supercomputers. Seismic surveys based on the latest innovations in this sphere can yield new, interesting and sometimes unexpected results.
In 2007–2008, specialists of the R&D Center at Gazprom Neft, together with Central Geophysical Expedition (CGE) carried out scheduled 3D seismic surveys within the vicinity of Noyabrsk, in areas that had been developed for a long time. The purpose of the surveys was to investigate internal architecture of reservoirs and develop their hydrodynamic models.
CGE enlisted the services of leading scientists from the Institute of Lithosphere Physics, Moscow State University (MGU) and other scientific organizations. Much work was done on physical simulation and theoretical calculations, but what was most important, a great set of geological-geophysical materials on the group of Gazprom Neft’s fields was thoroughly studied and specially reprocessed with the use of up-to-date tools and technologies.
The geological structure was thoroughly analyzed for an area of over 21,000 sq. km, including five large fields. It was found out that the whole of the area was characterized by well developed tectonic dislocations of unusual nature which were due to a system of horizontal faults in the pre-Jurassic basement. In the sedimentary mantle with oil and gas reservoirs these faults create a very complex system of fractures which shall be taken into account for improvement of field development efficiency.
Having analyzed the data obtained by processing and interpretation of survey results, the specialists of Gazpromneft R&D Center and CGE made an unexpected conclusion. Though the region was thought to be long since developed and thoroughly investigated, they found a considerable number of new prospective oil-bearing features occurring below previously discovered reservoirs. A new and very prospective area was located in the Jurassic system, YU1 and YU1-2 formations contain new reservoirs which remained undiscovered before. According to processed data the reserves of Etypurovskaya and Vingapurovskaya zones alone are estimated as 250 million tons. The whole of Noyabrsk region must have much greater resources.
The reliability of surveys has already been confirmed by drilling. Several old wells were deepened (300-500 m), the total average well depth reached 3,200 m. It should be noted that Jurassic reservoirs of this zone are not very thick and productive (up to 30-40 tons), whereas usual reservoirs of West Siberian fields reach 200 tons. But what makes the discovery extremely essential is that one practically does not need to drill new wells: to reach new oil-bearing formations it is enough to deepen existing wells. It makes development of such formations very attractive from economic point of view. Old and exhausted wells can thus have a new life.
Zonal upscaling performed by Central Geophysical Expedition shows that the new type of dislocations detected in the investigated area is rather widespread in central and northern regions of Western Siberia. Many fields, including giant gas fields of Gazprom located in the north of Western Siberia, must be affected by these dislocations. Continuation of such surveys will contribute to improvement of development efficiency and increment of hydrocarbon reserves not only in the new fields, but also in the ones that have been being developed for a long time.
It means that old oil regions of Western Siberia should be subjected to revision based on the latest achievements of international seismology and the most advanced technologies. The results can be most unexpected and quite positive.
Viktor Savelyev, General Director of Gazpromneft NTTS, thinks that the main conclusion to be made from the project results is as follows: “The lower deeper part of most old fields is not sufficiently investigated. Seismic surveys conducted as far back as the Soviet times provide no objective presentation of their complex structure.”
General Director of Gazpromneft R&D Center, Viktor Savelyev, sat down and discussed the state of seismic surveying with OGE.
Oil&Gas Eurasia: What is the role of research, development and engineering at Gazprom Neft?
Viktor Savelyev: The success of our company, like that of any other large oil company, depends of the level of applied technologies, their scientific basis and personnel qualification. Efficient management of formations located several kilometres below the earth's surface requires very good knowledge of geological, hydrodynamic and physical-chemical properties of both reservoirs and reservoir fluids. Therefore development programmes, digital mathematical models of reservoirs and production schedules developed by Gazprom Neft for each oil and gas field are based on abundant results of seismic, field, geophysical, physical-chemical and other surveys of reservoirs and wells. A great deal of research at Gazprom Neft is associated not only with prospecting and exploration of new commercial reserves of hydrocarbons, but also with implementation of measures in the sphere of reservoir engineering, oil refining, transportation, etc.
OGE: How are science and production related at your company? What is the path from idea to industrial introduction? How do you test ideas before wide-scale introduction?
Savelyev: First of all, the Research and Development Center currently has a considerable number of specialists with great work experience both in science and production. Their collaboration at different departments contributes to quite fast practical “expertise” of all scientific ideas. If in the long run specialists of a certain department manage to find a successful science-based method of solving a production problem, their suggestion is usually discussed by the company’s Scientific and Technical Council. If the opinion of Council members is favourable, the company can adopt a resolution on further more comprehensive testing of the new technology in production. The company’s most thoroughly tested proprietary technologies were more than once presented at meetings of Rosnedra Central Development Commission (CDC), international scientific conferences and seminars. The Center’s specialists have defended or prepared theses on a number of such subjects.
OGE: Could you give examples of specific results which, when introduced, contributed to increase in output, improvement of production performance, reduction of material expenses? Have any developments of Gazprom Neft scientists been a breakthrough in certain fields of knowledge or in advance of global practice?
Savelyev: 1. In cooperation with the service company Gazprom Neft-Noyabrskneftegazgeofizika Gazprom Neft specialists were the first to develop and introduce fixed measurement systems for individual control of reservoirs during commingled production with use of electric submersible pumps in a number of the company’s fields. The measurement systems are installed over the top of each developed reservoir on anchors in the production string. At present together with several St.-Petersburg military-industrial complex enterprises and service companies our specialists are improving the remote method of data transmission from the bottomhole to the measurement system. Introduction of the described information and measurement system made it possible to continuously control and manage several reservoirs during commingled production. Thus we were able to lower costs of drilling additional wells which we would have to drill in case of stage development.
2. Together with Schlumberger the company’s specialists developed and tested an absolutely new method of spectral acoustic and electromagnetic detection of water influxes from oil reservoirs in Karamovskoye field.
3. A group of Gazprom Neft specialists developed and introduced a new method and algorithm of adaptation of reservoir hydrodynamic models based on comprehensive results of geophysical and hydrodynamic surveys. In 2006 the method was considered and recommended for use in the RF by Rosnedra CDC.
4. In cooperation with the Russian State Oil and Gas University and Getek the company’s specialists were the first in the world (which was more than once confirmed at international conferences) to develop and introduce at the company’s departments an automated worksite (ARM) software system with “Hydra-Test-M” GDIS-TI corporate data base. It allowed to process, document, store and thoroughly analyse field research data at an absolutely new technological level.
OGE: Viktor Alexeevich, will you, please, tell us how Gazprom Neft R&D organises geophysical prospecting operations?
Savelyev: Most emphasis is placed on seismic surveying. The Prospecting Department includes a team than plans work scopes, that is determines the most promising exploration areas. Regional estimation of the area’s oil bearing capacity is performed by the company.
The objective of the Research and Development Center is to substantiate the need of work performance and select an appropriate procedure. The quality of data obtained from field works is very important. That’s why at the Research and Development Center we have organised a group responsible for overall supervising of field works.
Members of this group represent Gazprom Neft R&D in the course of field works, inspect the quality of work performance and observance of technologies, thus controlling regional contractors in charge of field works. After that the Research and Development Center accepts performed works, assessing their quality, and data is transferred for processing. In perspective the company will have its own processing center which we plan to open in St.-Petersburg jointly with Paradigm Company.
Processed data is interpreted by Gazprom Neft personnel as the company has specialists qualified in this field. Therefore targets of prospect and exploratory drilling are determined by the company’s specialists.
OGE: Was the Center’s next year plan affected by the crisis?
Just like in the whole of oil and gas industry and Russia, the global economic crisis makes us significantly correct our activity. We had to delay certain relevant works in the sphere of geologic exploration (for example, in new regions and offshore), limited a number of promising research and development projects in the field of development and surveying. Nevertheless, it does not mean that temporary difficulties will drastically affect the company’s general strategy of scientific and technical activity. We can only speak of freezing long-term projects long payback periods of which do not allow to implement them in the existing economic situation.
OGE: Which up-to-date technologies and devices are being developed in Russia and in the world? Does your company have any original proprietary technologies?
Savelyev: We mainly sophisticate and improve seismic surveying and everything that has to deal with it, for example, we are improving monitoring equipment (increase the number of channels and multiplicity) and system.
New methods of seismic survey data processing have appeared – multifocusing (Geomage), Stratimagic (Paradigm), Q-technologies (Schlumberger, WesternGeco).
It is western companies that are principal manufacturers, domestic companies mainly produce components. We are noticing active participation of Russian specialists working at foreign organisations in development of up-to-date technologies and mathematical support.
Gazpromneft R&D does not develop proprietary technologies and devices, but uses and adapts products of specialised service companies. The Center supervises field works and office processing (Paradigm dedicated processing center). As for seismic data interpretation, we intend to do it all by ourselves.
OGE: How do you see the future of geophysics and seismic surveying?
Savelyev: It is likely to be an effectively and dynamically developing branch.
The future of geophysics and seismic surveying is closely associated with scientific and technical progress. Computing capacities are developing very fast, which allows to start using new, more complex methods and technologies of monitoring, recording, processing and interpretation of seismic data in practice.
Certainly, the main trend is development and future domination of 3D multiwave modification allowing to increase the amount of useful data on subsurface resources several times. It obviously requires significant changes: sophistication of software, more powerful hardware for processing and interpretation of seismic data.
3D geodynamic and tectonodynamic simulation which is only beginning to develop today becomes one of the most relevant trends.
Still the most important thing is personnel qualification. Most specialists both in Russia and abroad are not able to solve the above-mentioned tasks as in terms of methods their work is based on fixed outdated concepts and models. As for the most promising trends, they have to deal with development of ideas of the predominant role of horizontal tectonic movements (do not confuse with orthodox pliotectonics) and rotation effects.