Heavy Crude Oil Recovery

Heavy Crude Oil Recovery

NATO ASI Series Advanced Science Institutes Series A Series presenting the results of activities sponsored by the NATO Science Committee, which aims at the dissemination of advanced scientific and technological knowledge, with a view to strengthening links between scientific communities. The Series is published by an international board of publishers in conjunction with the NATO Scientific Affairs Division A Life Sciences Plenum Publishing Corporation B Physics London and New York C Mathematical and D. Reidel Publishing Company Physical Sciences Dordrecht and Boston D Behavioural and Martinus Nijhoff Publishers Social Sciences The Hague/Boston/Lancaster E Applied Sciences F Computer and Springer-Verlag Systems Sciences Berlin/Heidelberg/New York G Ecological Sciences Series E: Applied Sciences - No. 76

Heavy Crude Oil Recovery edited by Ender Okandan Associate Professor Middle East Technical University Chairman Petroleum Engineering Department Ankara, Turkey 1984 Martinus Nijhoff Publishers The Hague / Boston / Lancaster Published in cooperation with NATO Scientific Affairs Division

Proceedi ngs 01 the NATO Advanced Study Institute on Heavy Crude 0 1 Recovery, Ankara, Turkey, June 21-July 4, 1982 Library of Congress Cataloging in Publication Data NHO Adnnc.,d Study inslilulc on Ilcavy Crude Oil Recovery (1982 : An~ara, Turkey) Heavy crude 011 recovery, (NATO advanced s cience InOlitUleS serie., Serle. Eo Applied.ciencu, v, 16) Include. Indu. 1. Oil flelds Production ""'t hods Congruses. 1. Okandan. ndec. I!. Title. Ill. SeriH. TN 863."314 1982 622',3382 84-1594 ISBN-13: 978-94-009-6142-5 e-isbn-1 3: 978-94-009-6140-1 001: 10.1007f978-94-009-6140-1 Distributors for the United States and Canada: Kluwer BaSion, Inc., 190 Old Derby Street, Hingham, MA 02043, USA Distributors for all other countries: Kluwer Academic Publishers Group, Distribution Center, P.O. Box 322, 3300 AH Dordrecht, The Netherlands All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or Iransmilted, in any form or by any means, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publishers, Martinus Nijhoff Publishers, P.O. Box 566, 2501 en The Hague, The Netherlands Copyright 1984 by Martinus Nijholf Publishers, The Hague Softcover reprint of the hardcover 1 st edition 1984

v PREFACE Within the last 10 years the world has come to a point where the easily explorable oil deposits have now been found, and it is anticipated that such deposits will be depleted by the beginning of the Twenty-first Century. However, the increasing demand of mankind for energy has caused technologists to look into ways of finding new sources or to reevaluat:e unconventional sources which, in the past, have not been economical. In this respect, heavy crude and tar sand oils are becoming important in fulfilling the world's energy requirements. What are heavy crude and tar sand oils? There is still some confusion as to their definitions, inasmuch as they vary among organizations and countries. In an effort to set agreed meanings, UNITAR, in a meeting in February 1982 in Venezuela, proposed the following definitions (see also Table 1): 1. Heavy crude oil and tar sand oil are petroleum or petroleumlike liquids or semi-solids naturally occurring in porous media. The porous media are sands, sandstone, and carbonate rocks. 2. These oils will be characterized by viscosity and density. Viscosity will be used to define heavy crude oil and tar sand oil, and density (oapi) will be used when viscosity measurements are not available. 3. Heavy crude oil has a gas-free viscosity of 100-10000 mpa.s (cp) at reservoir temperatures, or a density of 943 kg/m3 (20oAPI) to 1000 kg/m3 (10oAPI) at 15.6oC and at atmospheric oressure. 4. Tar sand oil has a gas-free viscosity greater than 10000 mpa.s (cp) at reservoir temperatures, or a density greater than 1000 kg/m3 (less than 10 0 API) at 15.6oC and at atmospheric pressure. 5. Heavy crude oils generally contain 3 wt % or more sulfur, and as much as 2000 ppm of vaniidium. Nickel and molybdenum are also frequently encountered. Heavy crude oil and tar sand occurrances are widespread throughout the world, occurring at depths from a few hundred feet to as great as 12000 feet, in rocks of various lithologies and ages.

VI Classification Viscosity (mpa.s) Density at 1S.6o C (kg/m3 ) Heavy Crude 100-10000 943-1000 20-10 Tar Sand Oil 10000 1000 10 Table 1. UNITAR definitions of heavy crude and tar sand oils (Ref: II. International Conference on Heavy Crude and Tar Sands, Venezuela, February 1982) The exact amount of such reserves is not accurately known, although in recent years applicable data seem to be more reliable. World total reserve estimates are given in Table 2 below. World Total Reserves (billion tons) Recoverable Reserves (billion tons) Cumulative Production (billion tons) Annual Production (billion tons) 600-1000 160 7 0,19 Table 2. Estimates of world heavy oil reserves and production~ (Ref: II. International Conference on Heavy Crude and Tar Sands, Venezuela, February 1982) Heavy crude oil deposits produce at very low primary recoveries when put into production. Conventional methods of enhanced oil recovery (EaR) are not feasible because of the high viscosity of crude oil and of unfavorable mobility ratios. The general classifications of EaR processes are: 1. Thermal Methods are steam injection and in situ combustion. Each method has several types of applications, such as cyclic steam injection, continuous steam injection, and dry in situ combustion -- forward or backward -- and wet in situ combustion. In these methods the viscosity reduction in crude oil is brought about by the application of heat into the reservoir. For steam injection, heat is injected in the form of steam, and for in situ combustion, heat is generated into the reservoir as a result of combustion reaction. KFigures are incomplete with respect to the USSR and the Peoples Republic of China.

World field applications of thermal processes are mainly concentrated in three countries, with approximately 150 active projects in the USA, 15 in Canada, and 55 in Venezuela. From this total, approximately 100 are in situ combustion applications, with the remainder being applications of steam flooding. 2. Chemical Flooding is accomplished by injecting chemicals in order to lower the interfacial tension between oil and water which mobilizes by-passed oil in the reservoir. Micellarpolymer flooding is the least tested, least proven and most complicated chemical flooding method to design. Problems still exist in the degradation of polymers and in reaction with divalent ions. In alkaline flooding, injected caustic solution generates in situ surfactants which lower interfacial tension and mobilize oil that is otherwise unrecoverable. 1979 statistics show that thermal methods outnumber chemical methods and that chemical flooding is tested mostly in the USA (more than 42 projects reported in 1982). 3. Miscible Flooding is a process where total or partial miscibility of C02' hydrocarbon gases, N2 or flue gas with crude oil is accomplished by injecting them into the reservoir under optimum conditions. C02 injection is attractive if C02 reserves are available at low cost. There are more than 20 field projects underway in various countries. The NATO Advanced Study Institute on Heavy Crude Oil was aimed at the discussion of EOR processes and the recent developments for their application in heavy crude oil deposits. The lectures given at the ASI, held at the Middle East Technical University, Ankara, Turkey, June 21 - July 4, 1982, are compiled in this volume. I would like to thank my colleagues in the Petroleum Engineering Department of the Middle East Technical University who helped in the organization and social programme of the meeting, and also secretaries imren Kiziler, for her help in typing the materials distributed at the conference, and Meral Ta?demir,for her careful typing of part of the manuscript. This NATO-ASI was made possible by a grant from the NATO Advanced Science Institutes programme and by the Middle East Technical University, whose facilities were made available for hosting the meeting VII Ender Ok and an

IX TABLE OF CONTENTS Preface v R.H. Jacoby Phase Behavior of Heavy Oils with Application to Reservoir Recovery Processes S.M. Farouq Ali Steam Injection -. Theory and Practice S.S. Marsden A Review of Use of Foam - Generating Surfactants to Improve Injection Profiles and Decrease Gravity Override in Steam Injection J. Burger Fire - Water Flooding from Principles to Field Applications 49 69 81 N. Mungan Carbon Dioxide Flooding - Fundamentals 131 C. Bardon, L. Denoyelle CO 2 Injection to Enhance Heavy Oil Recovery M. Klins CO 2 - Heavy Oil Flooding - Economic Design C.D. Stahl Micellar Flooding at Penn State N. Mungan Alkaline Flooding N. Mungan Fundamentals of Polymer Flooding T. Ertekin Principles of Numerical Simulation of Oil Reservoirs - An Overview S.M. Farouq Ali Mathematical Simulation of Thermal Recovery Processes INDEX 177 211 273 317 353 379 409 4125