well log data processing and interpretation
geological modeling

well log data processing and interpretation

The process of well log data processing and interpretation is performed in the following sequence:

  • Data acquisition and analysis. Well log digitizing along with quality control and assurance (QC/QA)

Parametric support of the seismic survey

  • Lithological subdivision and correlation of borehole log. Determination of compositional analysis and geoacoustic parameters: elastic wave interval velocity and elastic impedance

Petrophysical modeling

  • Obtaining and analysis of correlations such as "core - core", “core - well log”. Cutoff values substantiation of G&G parameters. Rock differentiation such as “reservoir - non-reservoir”, “oil & gas - water”

Allocation and analysis of reservoir rock saturation type by well log data

  • Quantitative evaluation of design conditions according to petrophysical models (such as net reservoir thickness, porosity, permeability, saturation)

general geological modeling of the object

A full range of geological and geophysical (G&G) data (results of seismic, gravimetric and magnetic surveys, integrated well log data, lithological and petrographical, paleontological, production and laboratory studies) is used for geological modeling of study areas (fields).

Interpretation of seismic survey data is carried out after a full cycle of processing procedures. Integrated interpretation and creation of structural and tectonic model are preceded by a careful study of modern concepts of regional geological structure, tectonic-physical mechanisms of structure formation, paleogeographic reconstructions and stratigraphy of the operational area. This approach allows to restore both the structural and tectonic and paleogeographic processes of the study object forming and get a "viable", most reliable model.

The process of geological modeling of the study area is performed in the following sequence:

  • Wavefield analysis

Seismic sequences are defined by the results of well log data and seismic stratigraphy analysis. Each seismic sequence is characterized by different seismic field properties that depend on conditions of sedimentation.

  • Velocity analysis and velocity modeling

Provides harmonization and binding of seismic horizons to the geological surfaces and velocity modeling. Vertical seismic profiling (VSP) data is used to conduct velocity analysis. A two-dimensional modeling along with creation of synthetic seismic gathers is conducted to validate the well tie. The result of the simulation is a velocity modeling and time-to-depth conversion.

  • Structural and tectonic modeling of the object

- tectonic modeling (fault modeling). Taking into account the faults, which are then adjusted and combined with each other, thereby obtaining a correct tectonic model;

- creation of a horizontal grid taking into account tectonic model;

- creation of a vertical grid taking into account well log data and time-to-depth conversed surfaces of reflecting horizons.

  • Attribute analysis

Attribute analysis of seismic data allows conducting of qualitative analysis of dynamic and kinematic parameters of the seismic field: amplitudes, phases, frequencies, speeds, impedances. The main objective of the attribute analysis is to establish links between dynamic characteristics and well log data of reservoir properties. In contrast to the borehole interpolation, attribute analysis provides a picture of the lateral distribution of lithology strata at great distances from boreholes.

  • Sequence-stratigraphic analysis

Sequence-stratigraphic analysis is based on the allocation and tracking of seismic sequences, which are limited by inconsistencies.