The Forward Modeling for Surface-borehole Observation Responses of Polarized Target

Surface-hole induced polarization method is a typical deep resource exploration technology, which plays an important role in the mineral survey. The traditional surface-hole induced polarization method is mainly to observe a single polarized secondary field. At present, the time spectrum observation of polarization fields is becoming more and more popular, which greatly enriches the interpretation technology of induced polarization data. In this work, the time spectrum induced polarization method is expounded, the decay polarization fields were numerical calculated and analyzed for the typical 2-dimensional geoelectric model. The results show that for a single polarized target, the time spectrum obtained from different azimuth observation responses are basically the same, which can effectively reflect the time-varying characteristics of the polarized fields. The observation responses of polarized target at different depths can still reflect the time spectrum of decay fields. The main change of the observed response of the polarized target closer to the borehole is the response amplitude. The conclusions and simulations of this study can provide working mode for relevant research and reference for similar work.

INVERSION OF ELECTROMAGNETIC LOGGING DATA IN A CLASS OF MODELS WITH A SMOOTH RESISTIVITY DISTRIBUTION

The article presents an alternative geoelectric model of the near-borehole space for electromagnetic logging data inversion in the class of models with a smooth and piecewise linear distribution of the electrical resistivity. We used ready-made ATLAS MPhM calculation modules, a library for python developed at the IPGG SB RAS.

FEATURES OF JOINT INVERSION OF NON-SIMULTANEOUS SIGNALS OF THE RUSSIAN LATERAL SOUNDING AND ELECTROMAGNETIC LOGGING IN CRETACEOUS RESERVOIRS

The article presents the results of the study of the effect of the non-simultaneous measurement of electrical and electromagnetic logging signals on the determination of the parameters of the geoelectric model by joint numerical inversion. The radial profile of the electrical resistivity is calculated for different times after drilling in the program for modeling the process of mud invasion into a porous permeable formation with parameters characteristic of the BS cretaceous reservoir. For this continuous resistivity profile electric log signals are calculated for the reservoir of unlimited thickness.

GEOELECTRIC MODEL OF THE VOSTOCHNO-SURGUTSOE FIELD JURASSIC RESERVOIR ACCORDING TO GALVANIC AND ELECTROMAGNETIC LOGGING SOUNDING DATA

The article presents the results of galvanic and electromagnetic well logs joint numerical inversion. Jurassic deposits are characterized by high contrast of electrical properties, resistivity anisotropy and dielectric polarization, that complicates modeling. Applying of modern methods of joint numerical inversion makes it possible to build detailed geoelectric models corresponding to the measured data in complex geological environments.

Application of ert method for identification of electric anisotropy in the Kluchi field area

The article presents the results of the measurements by electrical tomography methods in the area of the Kluchi polygon. Taking into account a priori well data, the parameters of the geoelectric model and the anisotropic characteristics of the reference geoelectric horizon, represented by shale, are determined. The anisotropy parameter can be used in priority tasks of nature management for the exploration and development of minerals, in environmental problems, to prevent dangerous natural and man–made phenomena.

Marlim R3D: A realistic model for controlled-source electromagnetic simulations — Phase 2: The controlled-source electromagnetic data set

Synthetic data provided by geoelectric earth models are a powerful tool to evaluate a priori a controlled-source electromagnetic (CSEM) workflow effectiveness. Marlim R3D (MR3D) is an open-source complex and realistic geoelectric model for CSEM simulations of the postsalt turbiditic reservoirs at the Brazilian offshore margin. We have developed a 3D CSEM finite-difference time-domain forward study to generate the full-azimuth CSEM data set for the MR3D earth model. To that end, we fabricated a full-azimuth survey with 45 towlines striking the north–south and east–west directions over a total of 500 receivers evenly spaced at 1 km intervals along the rugged seafloor of the MR3D model. To correctly represent the thin, disconnected, and complex geometries of the studied reservoirs, we have built a finely discretized mesh of [Formula: see text] cells leading to a large mesh with a total of approximately 90 million cells. We computed the six electromagnetic field components (Ex, Ey, Ez, Hx, Hy, and Hz) at six frequencies in the range of 0.125–1.25 Hz. In our efforts to mimic noise in real CSEM data, we summed to the data a multiplicative noise with a 1% standard deviation. Both CSEM data sets (noise free and noise added), with inline and broadside geometries, are distributed for research or commercial use, under the Creative Common License, at the Zenodo platform.

EVALUATION OF THE BKS LWD TOOL SPATIAL RESOLUTION BASED ON THE NUMERICAL SIMULATION RESULTS

Reservoir microimaging tools are currently one of the most high-tech devices used in wireline logging and logging-while-drilling. Based on a three-dimensional numerical simulation, the spatial resolution of the first Russian lateral scanning logging-while drilling tool was estimated. An algorithm for constructing a geoelectric model with an arbitrary distribution of electrical resistivity in the near-wellbore space is described.