Saint Petersburg 2018

Stratigraphic and lithological traps of hydrocarbons became known almost simultaneously with structural ones, but despite this, directed explorations of hydrocarbon accumulations in such traps began to acquire relevance only in the last decade. The main reason for this was the difficulty in determining the correct distribution of collectors. The distribution of reservoirs and/or saturation in the reservoir is a fairly complex task in the interpretation process, even if there is qualitative background information (during fieldwork, processing, etc.).

Today, many oil and gas companies during the process of exploration the field are faced with situations when the hydrodynamic and/or geological models and the real picture are different. In this paper, authors are going to show a way of combining all available information and using additional interpretation technologies that are calibrated with GIS data and the development history of the deposit. With the help of complexification, the process of distributing reservoirs of stratigraphic and lithological types of traps becomes more accessible, and data analysis is more intuitive and consistent with geological concepts.

Regularities of distribution of oil in the Bazhenov formation are determined by the initial concentrations in the rocks of the organic matter (OM) and its catagenetic maturity, that is, the formation of effective reservoirs in the rocks directly related to the process of catagenetic transformation of OM. In this regard, the need to involve geochemical studies in the assessment of resources and reserves of the Bazhenov formation is obvious. Proposed methodological approaches for the selection of effective thicknesses involving data from geochemical surveys and geophysical well logging for evaluating resources.

The main purpose for building a subsurface model is not only for better understanding of the field subsurface but also to define and optimize the field development plan. Depending on the field, the available data, and the application that is used, different companies may have different workflows for building the subsurface model. In most cases, the main input data for building a 3D geological model are wells data and seismic data, which from both data an interpretation and/or extra calculation need to be done.In this study, two different 3D structural models of the studied field were built based on the uncertainty of the interpreted seismic faults; hence two fault models and geological models were created. These geological models were taken for flow simulation analysis where the impact of flow across some of the minor faults in the field productivity was investigated.An integrated static and dynamic reservoir modeling workflow is presented using JewelSuite Subsurface Modeling software to quickly build multiple 3D structure scenarios, address the effect of different stratigraphic zonation, different fault connectivity, and/or different fluid compartmentalization, carry on fluids volumes quantification and study their dynamics in the porous media.

The exploration planning objects in LLC “LUKOIL-Western Siberia” are at different stages of exploration. Estimation of perspective resources changes in the process of studying the structure. It is based on available information and is subject to uncertainty. The volumes of reserves after opening may differ significantly from the PRMS estimate. It is also possible that geological exploration of geological exploration sites will not lead to a successful discovery. There is no absolute certainty that, provided that prospective resources are discovered, their development will prove to be economically viable.

This paper focuses on order statistic selection filters, where the filter output is restricted to be one of the input samples. In particular, we treat class of Weighted Order Statistic (WOS) filters, and the special filter class of Co-phased (CoPh WOS) filters. In the general case, the WOS filters possess a number of advantages in comparison with other filters, in particular, detail and edge preserving filters that are robust to outliers and sample contamination can be constructed. However, WOS filters are nonlinear and a theoretical analysis of their behavior is very difficult. Therefore, the using of the method of statistical trials for selecting the most effective project of the WOS filters (Data Mining) is drawing attention. Since this is time expensive, the increasing of computational productivity is of interest. In this paper, the technique of order filters adaptation invoking a method of statistical trials is considered, the approach to the attract graphical processors is presented, and results of processing a model of record of vibroseismic data are demonstrated.

Wellbore instability problems are often complicated and costly to solve and may endanger the success of the complete well construction process. For many years, different wellbore stability models are presented to study the state of stresses around the borehole and finally evaluate its stability or failure under the given circumstances. As the majority of the input parameters to the stability models are subjected to errors and uncertainties, therefore the model output, which is the minimum mud pressure required to prevent from the well collapse, is considered as an uncertain parameter. In this work, a Monte Carlo simulation as a quantitative probabilistic method is performed to assess the effect uncertainties in the input parameters on the performance of poroelastic stability model. Results of the Monte Carlo simulation for the given input parameters show that at mud pressures larger than 38 MPa, the probability of the wellbore stability is more than 90% and accordingly the wellbore collapse occurs with a probability of less than 10%. It also can be concluded that the probability of the well stability does not change significantly at different azimuth angles.

The possibility of prediction of the geologic section below the TD distinguishes the method of vertical seismic profiling (VSP) from all other methods of geophysical researches of wells. In the VSP method the incident waves and waves reflected from the seismic boundaries, located under the bottom, are recorded simultaneously. Thus, in contrast to surface seismic exploration, a more correct solution of the inverse kinematic and dynamic problems, aimed for the study of the section below the bottom, is provided. Several versions of the VSP method are currently used, each of which has a number of advantages and disadvantages. The combination of different versions allows one to study the elastic properties of the subsurface and the section under the bottom of the well by using of kinematic and dynamic parameters of waves of different types and classes. In the report the standard versions of the VSP, such as zero-offset and offset VSP as well as non-standard version –moving source VSP having a number of obvious advantages over the offset VSP at the forecast of the section under the bottom of borehole, - are considered. Experimental and model results for solving geological and engineering problems are shown for various versions of the VSP method.

In this research, we propose a new methodology for evaluation of recall factor in reservoir analogues identification problem. This factor provides the information about completeness of parameters set in order to identify ensemble of reservoirs. There could be various goals of analogues identification: geological similarity, PVT, production or something else. That is why it is important to know the precise volume of information, which should be provided. In this report data analysis techniques are performed for identification the essential set of parameters and providing the recall factor.

The Brinkman’s equation simplifies the numerical modelling of karst reservoirs by allowing the use of a single transport equation to model the flow of fluids in both the free flow and porous regions, in effect reducing the error arising from improper modelling of the interface between the two regions. However, most of the equations available to model flow within karst reservoirs deal with steady flow conditions. This approach however may not be accurate in reservoirs where unsteady conditions exist. We considered the effects of unsteady flow conditions in karst reservoirs by adding an unsteady flow term to the Brinkman’s equation. We solved the coupled conservation-transport equations that models unsteady fluid transport in karst reservoirs and then studied the effects of unsteady flow conditions on tracer transport in two different sample reservoirs. The solution method adopted is sequential and involves solving the unsteady Brinkman’s model first, followed by advection-diffusion-adsorption equation using the cell-centred finite volume approach. The same problems were also solved using a steady flow Brinkman’s model, and the results obtained were compared. were compared. The results show that, inside the caves, the unsteady Brinkman’s model yielded lower tracer concentrations at early times when compared to the steady flow model.

Western Siberia is the highest oil and gas province in Russia. This technical paper describes the lithological properties of Bazhenov Formation which have been evaluated in two different wells of Frolovskaya Region of Western Siberia. The estimated thickness range of the formation is about 20 25 m and is highly rich in siliceous shale. Due to abnormal deviation in GR (gamma ray) and TNP (thermal neutron porosity) Log, some sections of the formations have been identified as oil & gas rich zones. Moreover, a comparative study has been made between these two wells after interpreting different Logs. Using these lithological properties, certain field development plans can be made to produce the wells