A paleomagnetic record of geomagnetic secular variation during the last 3500 yr has been obtained from three lake sediment cores from lake Aslikul in the western Pre‐Ural region (Russia). Pollen data provide a time‐scale and relative paleotemperatures which can be compared with radiocarbon dated paleotemperature data for this region. Magnetic susceptibility measurements have been used for correlation between cores and reconstruction of composite core data. The paleosecular variations which have been recorded in the lake Aslikul sediments are consistent with results from West‐European lakes. Westward shifting inclination features are observed between the more western European and the Pre‐Ural regions which have apparent age differences between 200 and 600 years resulting in drift rates which are of the order of 0.1 degrees/year.

The objective of this study is to provide a well-dated point for a future palaeosecular variation (PSV) reference curve for western Russia. For this purpose archaeomagnetic and magnetic property analyses were carried out on a pottery kiln unearthed at the UNESCO World Heritage site of ancient Bolgar, having a rather precise age dating. The archaeological context provided an age between 1340 and 1360 C.E. The characteristic remanence vector was determined through alternating field demagnetisation and Thellier-Thellier palaeointensity experiments. Some innovations were introduced regarding palaeointensity. The check testing the equality of blocking and unblocking temperature was redefined. This allowed waiving the commonly used additional zero-field cooling steps during the Thellier-Thellier experiment. Another innovation concerns the calculation of archaeointensity at structure level. A Bayesian approach was introduced for averaging individual specimen archaeointensities using a prior probability distribution of unknown uncertainties. Next, an additional prior probability distribution was used to correct for cooling rate effects. This resulted in a lower uncertainty compared to common practice and in eluding time consuming cooling rate experiments. The complex magnetic mineralogy consists of maghaemite, multi-domain haematite and Al-substituted haematite. Some samples contained also some non-stoichiometric magnetite. The magnetic mineralogy was determined through hysteresis loops, backfield and remanence decay curves, measurements of the frequency-dependent magnetic susceptibility and through low temperature magnetisation curves. Accompanying hightemperature thermomagnetic analyses revealed an excellent thermo-chemical stability of the studied specimens. Directions obtained from alternating field demagnetisation and those extracted from archaeointensity experiments are congruent and have low uncertainties. The obtained archaeomagnetic results are fairly in agreement with global geomagnetic field models and contemporary PSV data of the wider area. The

Currently the super-viscous oil deposits are under active development in the Republic of Tatarstan. The general method of production is Steam-Assisted Gravity Drainage (SAGD). The problem of creation the complex of methods to monitor and control the reservoir processes caused by steam injection is of a great importance for increasing the development efficiency. Traditional control methods of shallow deposits development are normally based on seismic survey and whether insufficiently adatped for shallow deposits of super-viscous oil or very expensive. Thus, the special modifications of geophysical methods are required. The paper discusses general approaches used for creation of complex of methods for steam chamber monitoring the oil production from the shallow deposits of super-viscous oil by SAGD. The methods developed include seismic and geoelectric survey. In context of integrated monitoring technique creation the set of special core survey was conducted to define the possibility of detection of the steam chamber distribution by seismic methods. The distinguishing feature of the monitoring technology developed is the use of downhole monitoring tools to receive the seismic signal and to perform the geoelectrical field establishing. The article contains the description of the seismic data obtained processing methods and the results of the seismic data interpretation. The study was made with the financial support of Ministry of Education and Science of the Russian Federation (project № №02.G25.31.0170)

No abstract

The authors consider the technology for monitoring of shallow super-viscous oil (SVO) deposit development process aimed to determine the heated zones distribution corresponding to the drainage areas to enhance the efficiency of development process based on steam injection. The main objective of the work is to develop the monitoring approach based on downhole receivers and interpret the results of surface geophysical survey conducted with the use of downhole receiver tools. The downhole monitoring tools (receivers) are used to improve the sensitivity of the method and to decrease the environmental influence. Each tool includes 3 geophones located in metal case and is connected with the surface by wireline. The tools are set in the bottom hole of evaluation wells and the wells are abandoned. There are several factors influencing the seismic wave velocities (temperature, pressure, saturation etc). To provide more adequate interpretation geophysical methods with different nature are were to use in complex. The surface monitoring methods considered include shallow seismic prospecting and electrical prospecting. The results of periodical geophysical investigation are the maps of seismic wave propagation delay from surface source to the downhole receivers, electrode resistivity maps and interwell resistivity maps for different moments of time. Basing on the change of seismic wave ray velocity the heated regions are identified and the type of fluid saturation estimated with the use of resistivity mapping. The results obtained were used for the development planning including the injection pipe positioning. The interpretation results in terms of heated zones location obtained in the area of study was compared with the direct temperature measurements by periodical optical fiber thermometry conducted in horizontal producer wells. The possibility of steam injection process monitoring by surface geophysics with downhole receiver tools is shown basing on the real field case of shallow super-viscous oil deposit. The relations between geophysical fields considered and reservoir characteristics (temperature, saturation, pressure) are discussed. The work was supported by the Ministry of Science and Higher Education of the Russian Federation (project No. 02.G25.31.0170) and by the subsidy allocated to Kazan Federal University as part of the state program for increasing its competitiveness among the world's leading centers of science and education.