is reflected in location of microseismic focuses and the pressure curve measured during the fracking operation. Naturally, these phenomena should be factored in when designing a frac, which is not being done today in standard frac designing. An example of factoring in natural fractures when designing a frac is shown in figure.
OGE: Has investment by Russian production companies into geophysical investigation been sufficient? If not, why not?
Tikhonov: Today, the study of Bazhenov and Domanik deposits is “trendy” and Russia’s leading energy companies pay a great deal of attention to financing such activities. At issue here is investment into creation of new technology of geological exploration and tight reservoir development instead of spending funds on existing geophysical technology.
The brightest example is Rosneft’s JV with ExxonMobil, which has been tasked to study Achimov and Bazhenov deposits. Meanwhile, Rosneft’s other joint venture with Statoil will perform the same type of work on Domanik formations. Rosneft also supports scientific research on tight reservoirs, conducted at the Moscow State University.
Andrei Bezhenstev, Tigress Ingeoservice managing director
Oil&Gas Eurasia : In your opinion, what sort of geophysical investigation is still needed to properly understand the Bazhenov?
Andrei Bezhentsev : Detecting reservoirs in the Bazhenov suite requires the use of methods that enhance seismic data resolution, such as BE® technology by Geotrace. These methods are applicable both for summarized data and for CDP seismograms to improve quality of seismic routes at distant angles and the subsequent AVA inversion.
OGE: Would different approaches be taken to different parts of the Bazhenov?
Bezhentsev: The Bazhenov suite spreads throughout regions and its elastic properties are fairly good. On the most difficult blocks it is recommended to use the 3C multicomponent survey technology in addition to standard 3D seismic.
OGE: Is there sufficient 3D seismic? If not, where should more 3D seismic be shot?
Bezhentsev: As a rule, 3D seismic is conducted at the fields that are being developed and its total mapping coverage is definitely insufficient as many traps might be missed even within the boundaries of existing fields. In order to construct wells with greater precision, it is necessary to perform 3D survey in prepared areas as early as appraisal and exploration stage.
OGE: Given the fact that the shale layers are often not very deep – producing layers may be as little as 3 meters – is even 3D seismic enough? What sort of additional visualization techniques are necessary?
Bezhentsev: Seismic survey should by all means be used together with well data: logging info, core sample analysis. Without these it’s difficult to assess the porosity and permeability properties of the rock even at small depths. As regards visualization tools, currently there are many available in the market. Mostly, these are the tools that provide for three-dimensional seismic data visualization.
Yuri Solovyov, Schlumberger WL Geophysics Domain champion, Russia and Central Asia
Microseismic investigation is in use in the Bazhenov and Achimov. At the end of 2013, Schlumberger conducted