Himalayan Geology, Vol. 42 (1), 2021, pp. 205-210, Printed in India
Analysis of fracture density and their effect on mud loss in Asmari reservoir via FMI/FMS log, Rag-e-Safid oil field, SW of Iran
HOSSEIN TABATABAEI
Department of Petroleum Engineering, Islamic Azad University, Gachsaran Branch, Gachsaran, Iran
Email: tabatabaei.h@gmail.com
Abstract: Conventional logs of well logging, due to low resolution, fail to detect small-scale heterogeneities, including fractures of hydrocarbon reservoirs. However, these heterogeneities and fracture zones significantly affect the quality of the reservoir. Thus, it is quite important to identify the precise location of these zones for well completion, hydraulic fracturing, and the determination of the position of horizontal and diversion wells. In this study, images from Formation Micro Imager and Formation Micro Scanning logs were interpreted from three wells from the Rag-e-Safid oilfields (Iran). Fractures were identified and the results from these logs were compared with the mud loss logs and find a good correlation between mud loss data and fracture density. The analysis of fractures in terms of slope and extension, abundance, degree of opening, natural or artificiality and their effect on reservoir properties including porosity and permeability have been investigated. Also, with the evaluation of induction fractures and well wall fractures, the main and subsidiary stresses have been identified around the well wall. This study shows that only image logs can be interpreted for the exact location and attitude of fractures in reservoir. But if unavailable, other data such as mud loss data supplement to predict and approximate the fracture condition in oil field. They are mainly strike N70˚W-S70˚E direction and are chiefly observed in the upper Asmari zones. Image log showed a range of bedding dip from 25-40 degree with strike N67˚W-S67˚E in the well indicating of reverse limb in the field.
Keywords: Image logs, Rag-e-Safid oil field, reservoir rock, fracture Density.
