Seismic, Petrophysics, and Attribute Analysis to Evaluate the Tertiary Reservoir in the High Folded Zone, Kurdistan Region-Iraq

Abstract

 The present study is intended to evaluate one of the oil-bearing horizons in the “WN” oil field within the High Folded zone in the Kurdistan Region of Iraq, which represents a carbonate reservoir of the Tertiary units. Also, the picking and mapping of two other horizons of interest from the top and bottom of the reservoir horizon were done across the area. This work was achieved using 3D seismic data, check shots, and well logs. The methodology involved several processes including data loading, well seismic tying, horizon and fault identification and interpretation, velocity modelling, time-depth conversions, petrophysical analysis, and 3D properties modelling. Isochron and depth maps for three horizons and two isopach maps were constructed. An asymmetrical doubly plunging rollover anticlinal closure with a length of 6.4 km and width of 3.5 km is identified on the reservoir maps that trend in the East-West direction. Faults were identified and extracted manually and automatically. A total eighteen of minor reversal faults striking the northern flank of the anticlinal closure were interpreted. Variance, Chaos, and Ant Tracking attributes were selected and applied successfully helped to better visualize fractures and automatic fault extraction. Petrophysical Analysis and cross-plots demonstrated that the reservoir consists of dolomite, lime dolomite, and anhydrite limey dolomite. The petrophysical properties revealed the average of each effective porosity, secondary porosity, permeability,