3D Seismic
(Service)
Online Support Service: No
Interpretation of Data: No
Description:
The main geophysical methods used in the search, exploration and monitoring of oil and gas fields are well logging (GIS), surface seismic (2D and 3D) and in wells (VSP, NVSP). GIS methods have high resolution in depth, however, they study the closest area near the well. Surface seismic has the ability to obtain a coherent image of large objects, but insufficient resolution and accuracy to solve problems of high detail. VSP provides more detailed study of the near-wellbore space compared with ground-based seismic exploration, but in a limited range of distances from the well. During production drilling for oil and gas, the need often arises for a detailed study of productive formations at distances up to 1.5 - 2 km from the well, which are not achievable for VSP studies. The presence of a deep well can significantly increase the accuracy and detail of 2D or 3D seismic surveys in the vicinity of this well if simultaneous observations on the surface and in the well are used, that is, the advantages of surface seismic and VSP are combined. The technique of combined observations, in which excitations on the surface on a 2D profile (or 3D grid) are recorded by a VSP probe located near the bottom of a deep well, is called the “Local 2D + VSP project” (“Local 3D + VSP project”, respectively). In fact, the proposed technology is based on three-dimensional surveillance systems.
Overview:
Disadvantages of surface seismic (SP)
- Lack of information on the distribution of the true propagation velocities of longitudinal and transverse waves
- Lack of accurate waveform information
- Subhorizontal Model Migration
findings
- Surface seismic survey solves the main modern exploration tasks, but has fundamental limitations: - uncertainty of the velocity model, - uncertainty of the waveform, - simplified model of the environment for migration.
- The VSP provides an unambiguous solution to the problem of binding reflections on the surface and the study of the near field, but all modifications, including 2D VSP and 3D VSP, have significant fatal flaws associated with the asymmetry of the geometry of the observations.
- The combined observation systems 2D + VSP and 3D + VSP allow solving the following problems:
- refinement of the speed model
- true waveform estimation
- implementation of vector model-based migration.
- Three-dimensional observation systems and model-based processing can be recommended as one of the ways to increase the information content of seismic exploration to meet the needs of the oil industry.
The current state of reserves and the rate of exploitation of oil fields puts on the agenda the need to significantly increase the permissibility and accuracy of the study of productive formations for the recovery of residual reserves and exploitation of small complex fields. The proposed use of three-dimensional observation systems (3D + VSP) provides an opportunity to combine the advantages of surface seismic and VSP, which can fundamentally increase the information content of seismic exploration.
OOO "Geovers"
Locations: Russia, Saint-Petersburg
Main Products/Services: Application software development for processing and interpretation of seismic data, processing and interpretation of VSP data in conjunction with GIS and ground seismic
Registration: Russia, Saint-Petersburg