Gazprom Neft has confirmed the completion of electrical prospecting (to a length of 3,000 kilometres) undertaken throughout an area of approximately 600 square kilometres at the Tympuchikansky and Vakunaysky blocks (the Chonsky project) in Eastern Siberia.
The recently completed works represent the most significant research to date* undertaken through the use of near-field transient electromagnetic (TEM) method**, not just in Eastern Siberia, but in the world. Records were broken not just in the extent of electromagnetic field sources and the number of signals received (at around 1,200 and 7,600, respectively), but also the duration of the works — undertaken since December 2013 without any break for the off-season. These investigations have allowed the collection of a significant volume of new geological information on the Tympuchikansky and Vakunaysky blocks. Electrical prospecting of around 1,500 kilometres was also undertaken at a third field within the Chonsky group, at the Ignyalinsky block.
Near-field transient electromagnetic survey is just one part of a comprehensive programme of geological prospecting being undertaken by Gazprom Neft at the Chonsky group fields — the combination of seismic and electrical prospecting allowing more accurate mapping of geological formations. Highly precise 3D seismic prospecting reveals the existence of potential reservoirs (and their shape), while electromagnetic frequencies can indicate the extent to which such formations are saturated with hydrocarbons. The large number of transmitters used at the Chonsky project allows deep coverage of the zone under investigation, forming the basis for more detailed maps of the resistance of various layers, at various depths (from 50 metres to 1,700 metres at the Chonsky fields).
Electrical prospecting at all three fields of the Chonsky project will be continued in January 2015, with a total 7,500 metres to be covered in the next season, using new recording equipment currently undergoing testing — something which is expected to both shorten the lead time while improving the effectiveness of such work.
First Deputy CEO Vadim Yakovlev commented: “The establishment of a new Gazprom Neft E&P centre in Eastern Siberia is a major strategic focus for the company. The entire region is noted for the low level of geological research undertaken here, so the new, precise data we are collating through the use and integration of various cutting-edge geological prospecting techniques will allow us to develop an optimally effective model of these fields, allowing us to begin commercial production in a few years’ time.”
* Data obtained from the electrical prospecting contractor, Irkutsk.
** Near-field transient electromagnetic (TEM) method is the most widely accepted and advanced pulse inductive electromagnetic survey technology both in Russia and abroad. A system consisting of ungrounded transmitting loops and receiving loops placed on the surface is used in the survey; the dimensions of the loops are determined by the profiling depth required. The field is excited in the medium being surveyed by switching the current in the transmitting loop on and off.
The Gazprom Neft Chonsky project comprises three licensed acreages — the Ignyalinsky, Tympuchikansky and Vakunaysky fields, located at the border between the Irkutsk Oblast and the Sakha Republic. Total reserves at the project are estimated at 125 million tonnes of oil and 225 billion cubic metres of gas. Gazprom Neft is working with Japan’s JOGMEC at the Ignyalinsky field, and developing the other two fields independently.
- Exploration and production photo gallery: