The Study of the Influence of Stratigraphic Structure on Seismic Attribute Analysis

Abstract

Seismic attribute analysis is an important tool for reservoir prediction. In the process of attribute analysis, the choice of attribute extraction parameters is always determined by the characteristics of attribute itself, which ignores the analysis of the stratigraphic structure. There may be some artifacts in such results, which can lead us some wrong ideas. In this paper, a detailed analysis of the influence of different formation structures on the target layer is made, and the corresponding countermeasures and suggestions are put forward. 1) Energy shield of upper strong reflector. When there is a strong reflective interface over the target formation, such as igneous rock, conglomerate, coal seam and so on, most of seismic energy will be reflected. Then the extracted attributes along the target formation can't accurately reflect the change of reservoir, and we should compensate the attenuation of energy firstly. 2) The coverage of the strong reflection interface side-lobe. When the distance between the target formation and the strong reflection formation is less than one seismic wavelength, the strong reflection's side-lobe will interfere with the reflection of the target formation, and the effective signal of the target formation is completely submerged. For this case, we should remove the strong reflection before attribute analysis. 3) The interference of the adjacent interface. When there is a reflection interface whose reflection energy is equivalent to the target formation's and the distance to the target formation is less than one wavelength, its reflection will interfere with that of the objective formation. Obviously, the attribute extracted along the target formation not only contains the information of the target formation, but also contains the information from the adjacent interface. In practical application, the distance should be analyzed. Which reflection (the top or the bottom) should be used when analyzing attributes of single sand has also been studied. The results show that the selection of time window should be based on the stratigraphic structure. If there is no change in the distance between the adjacent interface and the top of the sand, and the physical properties of the up surrounding rock almost have no change too, then we can use the top reflection information to extract attribute. But if the below stratigraphic structure matches the above conditions, the bottom reflection information should be used.

AAPG Datapages/Search and Discovery Article #90291 ©2017 AAPG Annual Convention and Exhibition, Houston, Texas, April 2-5, 2017