Geomodel 2012 - 14th EAGE science and applied research conference on oil and gas geological exploration and development

Paleozoic complex within the West Siberian basin is considered as a hydrocarbon prospective object. It is known that supergene reservoir of upper part of Paleozoic basement can contain fluids. In this article an integrated approach to the supergene reservoir detection and mapping is described. Firstly gravity and magnetic exploration data was used to work out a structural model of the Central Uvat region. Then core data was used to connect potential field data and lithological composition of the basement rocks. Also seismic attributes and seismic facies analysis were involved to detect fracture zones in the upper part of the basement and define shapes of geological bodies. Combining all the data potential reservoir rocks of the upper part of the basement were mapped

Last years when anticline traps in West Siberian basin are almost studied, the most urgent became facies analysis of clastic sediments, which allows to predict lithological traps and optimize the development of drilled deposits. This work is an example of facial conditions recovery using core and log data of the Upper Jurassic productive deposits on one of the fields within the Yamalo-Tazovskaya megasyneclise. There are two Upper Jurassic producing layers: U1-1 and U1-2. Core data from 5 wells and well logs from 31 wells of the same field were analyzed. Based on the core data the layer U1-2 was identified as terrigenous alluvial and delta, while the layer U1-1 consists of terrigenous delta and coastal-marine deposits. Well logs data was also used to specificate the facial scheme with curve models

The hydrocarbon productivity of Paleozoic carbonate reservoirs has been proved in the offshore prolongation of the Sorokin swell. The Prirazlomnoe oil field was discovered in 1989 by the prospecting well No.1 drilling to the depth 3100 m in the dome part of the anticline fold. The productive horizon is represented by two carbonate beds of different composition and origin. The upper highly porous bed of Asselian age is built by organogenic-clastic limestones and overlaid by shales of Artinskian-Kungurian age. The method of capillary saturation of rocks, designed to assess the structural features of the complex void space of a carbonate reservoir, enables to evaluate the ratio of voids of different types, namely the content share of pores, voids and fractures, i.e. to evaluate the complex reservoir type. This evaluation includes fractures of various orientation that determine the direction of filtration and isotropic rocks permeability, morphology and genesis of voids – the emergence of "newly generated" vug and development of the "inherited" vug; the characteristic of fractures variations with depth, different intensity of fractures in rocks and substantiation of rocks fractures changes in the reservoir

On the basis of reprocessing and reinterpretation of CMP-2D seismic data along regional lines, acquired on the territory of platform Bashkiria in the beginning of the XXI century there were allocated 8 potentially prospective hydrocarbon objects in the deposits of the Riphean clastic-carbonate sequences. One of them is Kushkul structure of inversion type in the deposits of the Lower Riphean age of Kama-Belskaya depression (KBD), located in 20 km. to the East of Kushkul field in the Paleozoic deposits. It is recommended to make a thickening network of 2D lines with the aim of updating the geological model of the object and choosing an optimal point of a prospect well location in the Riphean deposits

As a result, complex analysis geological and geophysical data for regional work was a map of the surface of the Vendian in south-eastern part of the South Tatar arch. The main elements of the Vendian and Early Paleozoic tectonics in relation to their potential oil and gas content. It is suggested for the origin of the inversion Shkapovskoy structure

The contributions of global navigation satellite systems, such as the GPS, for source and receiver positioning and timing are highlighted. While GPS positioning has been used for several decades, the impact of GPS timing on land acquisition is recent (2005). By enabling the time-stamping of all seismic samples in the recorder as well as in the autonomous receiver stations, it offers the possibility to synchronize all elements of a hybrid spread made of cable-based and cable-free segments. The same flexibility is present on the source side as soon as vibrators are able to define by themselves the position and the start time of each shot (T0). By combining these possibilities different acquisition architectures are made available to improve productivity depending on terrain conditions

Wind noise, traffic noise, and non-stationary impulsive noise seriously degrade the quality of non-explosive seismic data in many regions. Vertical stacking in the field or two-dimensional noise suppression procedures (such as FK) at the processing stage can not attenuate high-amplitude noise of the mentioned types. At the same time, non-stationary noise can be efficiently removed at the stage of data acquisition by diversity stacking. This procedure does not distort the initial relative amplitudes of the signal and consequently can be recommended for wide adoption. The parameters of the diversity stacking should be selected during the field trials

The article tells about the way of eliminating the neighboring source positions interference when carrying out field seismic works by Slip Sweep method. The principle of struggle with disturbance is based on frequent filtration of the received signal on the stage of obtaining vibrorecords to slip sweep convolution. Since the interference from neighboring SP is artificial with known parameters, therefore it is predictable. Using this property and applying the time-variable frequent limit filter (tracking filter) the author was able to suppress the wave-interference significantly pointing out the useful signal. In addition, irregular waves-interference (microseisms) are removed. This method allows increasing vibroseis source productivity in several times not only without quality deterioration, but also with improvement compared to Flip flop standard method

This report describes specificity of seismic surveying in the Islamic Republic of Mauritania on a strip of saline salt marshes and salt lakes (sebkha), which stretch along the low-lying sandy coast. To overcome these conditions and to achieve maximum quality during drilling, seismic unwinding and registration of seismic waves have been used non-standard techniques. Despite the complexity of the seismic survey taken by organizational and technical measures on the part of the performer and the supervisors contributed to the achievement of good quality seismic data, which allowed them to successfully carry out further processing and interpretation, geological solve all problems