The first investigations by the LFS technology were conducted on the Romashkinskoye oil field (Republic of Tatarstan, Russia) in 2003. There were a series of experimental works to test the physical background of the method. From 2003 to 2011 we continue investigations on this oil field, also we collect data from another oil fields on the South-Tatar arch and from the western side of Melekess depression (Novo-Elhovskoe, Sarapalinskoe, Uratminskoe, North Zyuzeevskoe, Glazovskoe, Zarechnoye deposits, etc.)
The researches were also conducted outside the Republic of Tatarstan - in the Republic of Udmurtia, Republic of Kalmykia, Republic of Komi, Samara and Orenburg regions, Yamalo-Nenets, Khanty-Mansi autonomous Okrug of Tyumen Region, and Bulgaria.
Basically, the technology was applied to the already discovered oil deposits to refine the contour of oil-bearing zones and determine suitable site for drilling. There are some cases when we identify large oil deposits in the sediments of the Middle and Lower Carboniferous within the eastern side of Mellekess depression.
Physical theory of the LFS method was developed by the “GRADIENT” company with collaboration of Kazan State University from 2002 to 2005. Currently we improve our field equipment, processing and interpretation techniques. To find more information, please visit the History of the development.
The main aim of the LFS method is the identification of oil and gas accumulation zones and determination the suitable drilling site by the analysis of microseismic background at the observation point.
See details in Low-Frequency Seismic Sounding Method
The method is based on the effect of seismic wave’s resonance in low-frequency range between the daylight surface and the oil-gas deposit.
See details in Physical theory of the method
The Success rate is more than 86,3%
See details in Efficiency of technology.
Gradient Company has the following equipment at its disposal:
- Lennartz seismic receivers;
- Stand-alone seismic recorders (ARSS);
- Electrochemical seismic receivers (SME411);
- SM-3kV kit.
See details inTechnology of field works
limitations are due to three factors:
1. Diffraction effects that determine the smearing of the anomalous zone at the edges of the reservoir, depending on the depth;
2. Effective thickness, porosity coefficient and oil-saturation coefficient of the reservoir, that defines a contrast of wave reflections in low-frequency range;
3. Character of natural and anthropogenic sources of seismic waves that determine the possibility to get a clear signal from background noise.
Such statistics is not performed yet. Our customers provide information only about wells that have been recommended by LFS and do not provide the information by the subsequent drilling results. Discrepancy may be due to insufficient intervals between pickets and limitations of the method described above.
In general, we believe that the anomalous reflection of seismic waves in low-frequency range correlates with effective thickness of oil-saturated reservoir, porosity coefficient and oil-saturation coefficient. This correlation is proportional but nonlinear. Correlation function tends to the horizontal asymptote, so that subsequent increasing of physical parameters will not make significant changes in the spectrum.
You specify the oil production rates of wells from 22,5 bbl/day to 47,5 bbl/day, which investors do not consider profitable for depths more than 1 km and indicate as a lack of industrial deposits. Do you recommend drilling in these zones?
Such debits are profitable for the Republic of Tatarstan. Oil production rates in some wells, drilled by our recommendations in the Yamalo-Nenets Okrug were 730 bbl/day and above.
Anomalous reflection of seismic waves in low-frequency range changes the shape of spectrum and increases the amplitude at defined frequencies. We can get the correlation between the intensity of spectral peaks and physical parameters of oil reservoir (porosity coefficient, oil-saturation coefficient, effective thickness of oil-saturated reservoir), but we need a huge statistics obtained by the drilling in the same geological conditions.