Far East Hydrocarbons 2019

The geological section of Eastern Siberia is an extremely difficult object to study. The quality of accounting for the anomalies of the upper part of the section greatly affects the accuracy of structural constructions. Due to the lack of information about the upper part in the processing and interpretation of seismic data, the problem of structural constructions does not have a single solution. The approach to predicting the depth-velocity model of the upper part of the section, based on the original method of restoring the elastic-velocity characteristics from these probing field formation in the near zone using well logging data and vertical seismic profiling, reduces errors when considering anomalies and significantly improves accuracy structural constructions.

In 2017 a vertical appraisal well was drilled on the prospective structure of the Ayashsky license area (shelf of Sakhalin Island) and a new large multi-layered oil field was discovered. This article presents a methodology for complex assessment of reservoir geology and further production strategy on the base of analysis of numerous geological realizations of 3D reservoir properties such as lithology, porosity, water saturation and permeability. For each geology realization streamline analysis was provided for the case of five-spot vertical production and injection well system. As a result, on the early stage of reservoir modelling the influence of geological parameters on the fluid flow was assessed. Further, entire array of calculations was analyzed in terms of the reservoir hydrodynamic connectivity and volumes of recoverable oil. The final geology realization was selected on the base of statistical distribution of reservoir parameters and then used for full hydrodynamic modelling and analyzing of sensitivity to the main production uncertainties.

The results of multiple studies show that wettability influences on the residual water- and oil saturation, reservoir oil- and gas-condensate recovery, types of relationships between capillary pressure and saturation and many other reservoir properties. Together with this, in recent years the method of nuclear-magnetic resonance (NMR) has got a wide application at determining the filtration-capacity (permeability and porosity) properties (FCP) of rocks. Our laboratory has carried out the study of core samples where at each stage of wettability determination by the USBM method the measurement of samples on NMR-relaxometer is run. The results obtained demonstrated a high convergence of determination of water-oil saturation by NMR method and by centrifuging what permits to refuse from using a very expensive method of water-and oil saturation determination by Ultra-Rock Centrifuge in favor of NMR relaxometer and centrifuge, which enables to perform centrifuging in the system oil-water and water-oil.

In this paper, we use the vector finite element method for 3D-magnetotelluric field modeling using the primary-secondary field approach. In this paper, instead of a complex-valued system, its real analogue of two real-valued equations is used. To solve the internal system, the direct PARDISO method is used. This approach is applied to one of the sites within the Far Eastern Federal District.

An integrated approach is applied to assess the oil and gas potential of poorly studied areas on the example of the Leno-Vilyujskoj oil and gas area.

This article is intended to classify problems of the filtration parameters justification for reservoir models and to classify problems of pore-scale modelling applications for solving of classified reservoir modelling problems. There are four highlighted classes of pore-scale modelling problems with examples from real cases: problems of reliable initial data obtaining, problems of joint modelling of various processes using such models, problems of rescaling of obtained results through all existing scales of a reservoir, various organizational problems that affect the effectiveness of applications. Performed problems classifications allowed to highlight four key advantages of pore network modelling and its application examples from real cases. These key advantages can help to solve highlighted pore-scale modelling problems: less number of equations and their simplicity what significantly reduces the requirements for computational resources and make simpler using high-performance computing, relatively small number of parameters that defines a model of porous media what makes it possible to effectively construct such models and solve different inverse problems, the rescaling of models by the study of correlations of determining parameters of pore network models and parameters of reservoir models, the ability to use generalized results of more complex methods and experimental data in calculations using pore network models.

The approach to 2D inversion of the induction logging data and the software are developed. The approach is based on the finite element method for calculating the electromagnetic field and on the use of the Gauss-Newton method for the minimization of the regularized residual functional for 2D inversion. The possibility of the correct 2D inversion performed independently on the logging tool trajectory sections is shown. This allows the effective parallelization of the 2D inversion on the trajectory sections, 2D processing of the quite long trajectories of the logging tool motion during relative short (several dozens of minutes) time, and, as a result, significant improving the quality of the obtained geoelectrical model of the near-wellbore region.

The Discovery of the Neptune (2017) and Triton (2018) Oilfields Confirmed the Productivity of the Entire Complex of Nutovo deposits in the Northern part of the Okhotsk shelf of Sakhalin island. The new data allowed to develop a methodology for the study nutovo sediment. It allows to reasonably predict the accumulation area of reservoirs and intraformational sealing horizon to seismic and drilling data. Even in the absence of wells directly within the 3D survey. This is especially valuable for the analysis of further prospects of the upper-nutovo sub-horizon, the productivity of which is associated with the oil reservoirs.

Abstract describes an application of ultra-deep reservoir mapping while drilling inversion for seismic calibration while drilling which significantly improves reservoir structure prognoses for better well placement and NTG increase.

Within the Republic of Sakha (Yakutia) and the Khabarovsk territory, electromagnetic (TEM) and magnetotelluric (MT) reconnaissance surveys were carried out. Electromagnetic studies within unexplored regional structures provided the structural and lithological features of the section, including sedimentary rocks pinch-out zone. Obtained data allows identifying the most promising areas with joint seismic and EM exploration.