Evaluation of Fractures and Asphaltene Formation Relation in Asmari Reservoir, Kupal Oil Field
Subject Areas : Petroleum GeologyBahman Soleimani 1 , َAghil Heidari 2 , Shahram Taghavipour 3
1 - Shahid Chamran university, Ahvaz
2 - Senior expert in the NISOC, Ahvaz, Iran
3 - NISOC
Keywords: Image logs, Asmari reservoir, Kupal oil field, Fracture system, Asphaltene ,
Abstract :
The study of fractures plays an important role in understanding the behavior of the reservoir, and this role can be reduced by the process of asphaltene deposition. Its most important aspect is in the migration of reservoir petroleum fluids. In this article, an attempt has been made to investigate the effect of fractures on the formation of asphaltene in the Asmari reservoir of Kopal oil field located in North Dezful embeyment by using different Image logs, OBMI-UBI. According to the pattern of fractures related to folding, most of the fractures are of the type of oblique and longitudinal seams. The lower sandstone layer is characterized by the most fractures and mostly of the open type. Most of the open fractures were identified in the lower half of Asmari (consists of mudstone and sandstone). The examination of open fracture density shows that zones 2 and 3 have the highest and zone 4 has the lowest fracture density. According to the direction of collapse fractures caused by drilling, the direction of maximum horizontal stress (δHmax) is N55E and the direction of minimum horizontal stress (δHmin) is N35W. This direction corresponds to the general direction of Zagros. The data on mud loss showed that the maximum value corresponds to the location of the concentration of fractures. The results of the analysis of oil samples showed that the percentage of asphaltene in the Asmari reservoir is low and has no relation to the production time in different wells. The percentage of asphaltene varies from 0.6 to 2.75%. In general, primary asphaltene does not exist in oils. The increase in the percentage of fractures in the reservoir compared to the depth is also associated with the increase in the percentage of asphaltene produced. Key words: Image logs, Asmari reservoir, Kupal oil field, Fracture system, Asphaltene