Calculation Of Oil And Water Relative Permeability For Extra Low Permeability Reservoir.

SPE 137396 Giant Field (A) ROS Study
S. Serag El Din, Abu Dhabi Company for Onshore Oil Operations (ADCO); Y. Al Hammadi, (ADCO) and M. Z. Kalam, (ADCO)
Copyright 2010, Society of Petroleum Engineers This paper was prepared for presentation at the Abu Dhabi International Petroleum Exhibition & Conference held in Abu Dhabi, UAE, 1–4 November 2010. This paper was selected for presentation by anSPE program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been reviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material does not necessarily reflect any position of the Society of Petroleum Engineers, its officers, or members. Electronic reproduction, distribution, orstorage of any part of this paper without the written consent of the Society of Petroleum Engineers is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of SPE copyright.

Abstract A study was aiming to evaluate the remaining oil saturation (ROS) behind theflood front using Liquid Trapper technology and open hole logs. Four (4) wells were included in this study, two in the South and two in the North of the field. These wells were selected in areas highly flooded by peripheral water injection. The objective is to improve the description of ROS and better estimate the oil recovery efficiency from the field. The Liquid Trapper Coring technique is used toprovide more accurate oil saturation data for the reservoir model. It was used in this project in particular to evaluate the remaining oil saturations in the flooded reservoir zones. The Liquid Trapper Coring is a technique to capture any oil that is expelled from the core (due to pressure change) by gas expansion as the core is raised to the surface. This volume of escaping oil can then becalculated over selected intervals and incorporated into the standard saturation analysis performed on the whole core sections. The oil saturation determination from core would give the expected remaining oil where as the oil captured in the trapper barrel would indicate any movable oil in the reservoir. The inner tube of the Liquid Trapper is made of stacked modules, 1m in length and each made up ofclosed 'cells'. The cells allow capturing of the expelled fluids and segregation of oil, water and gas due to gravity difference. The fluids in the cells surrounding the core are collected to be added to the volume of oil saturation in the core. The volumes were measured in the laboratory by centrifuge and were added to the saturations measured using Dean Stark method. This case study presents theresults and uncertainties of using Liquid Trapper Technology in ROS determinations behind flood front of water invaded carbonate reservoir zones. An assessment of this new technique, and its pitfalls in onshore reservoir applications is compared with conventional sponge core coring. Introduction Nowadays increased emphasis is being placed on secondary and tertiary recovery techniques. An accuratemethod to determine the residual or remaining in-situ hydrocarbon saturation is required in order to establish if there are sufficient hydrocarbons left in the reservoir to make a recovery process worthwhile. Several methods of obtaining the necessary hydrocarbon-saturation data are available, including Sponge Coring and Liquid-Trapper Coring. The two major problems that are known to alter thefluid content are mud-filtrate invasion and the expulsion of liquids from the core due to gas expansion during the pull out of hole trip. The flushing of liquids due to filtrate invasion can be minimized by using the right mud design and by controlling operating parameters. Moreover tracers are used in the mud fluid, which permit determination of the amount of filtrate in a core sample. To cope with...