Publications

Steam injection in Duri Field is designed to: 1. reduce oil viscosity. Duri has highly viscous when cool (>100 cP @100 oF) and has oil gravity ranges from 17 to 23 API. 2. maintain formation pressure. With over 7000 wells, Duri Steam Flood project is the worlds largest steam flood. Two primary and several secondary producing zones with multiple sands are present. There are unique aspects of Formation Evaluation to consider in both open and cased well analysis in a heavy oil environment. It has been demonstrated that the steam reacts with rock minerals causing mineral dissolution (quartz and feldspar) and precipitation (authigenic smectite). This reaction has effected open hole logs reading and can result in misinterpretation. It is desirable for reservoir management to correct the logs, and thus enable a more accurate estimation of rock properties, so that moveable oil and depletion may be identified in the later stages of the steam flood. Formation Evaluation workflows have been tailored for heavy oil that may be utilized to accurately estimate porosity, permeability, and water saturation. To validate the evaluation, core data, XRD and saturation log have been used. To estimate remaining oil volume in the presence of steam chests has recently applied a three-phase (steam/oil/water) saturation algorithm by developing time-lapse saturation and temperature profiles from pulsed neutron capture, Carbon/Oxygen, and temperature logs in cased hole. The time-lapse profiles are then applied to findbypased oil, estimate remaining reserves, identify depleted zones, and influence steaming strategy. Infill well drilling and heat management projects rely on this evaluation.