1、 Methods for Determining Inputs to Environmental Petroleum Hydrocarbon Mobility and Recovery ModelsRegulatory and Scientific AffairsAPI PUBLICATION NUMBER 4711JULY 2001Methods for Determining Inputs to Environmental Petroleum Hydrocarbon Mobility and Recovery ModelsRegulatory and Scientific Affairs
2、DepartmentAPI PUBLICATION NUMBER 4711JULY 2001PREPARED UNDER CONTRACT BY:Tom Sale, Ph.D.Research ScientistDepartment of Chemical and Bioresource EngineeringColorado State UniversityFOREWORDAPI publications necessarily address problems of a general nature. With respect to partic-ular circumstances, l
3、ocal, state and federal laws and regulations should be reviewed.API is not undertaking to meet the duties of employers, manufacturers, or suppliers to warnand properly train and equip their employees, and others exposed, concerning health andsafety risks and precautions, nor undertaking their obliga
4、tions under local, state, or federallaws.Nothing contained in any API publication is to be construed as granting any right, by impli-cation or otherwise, for the manufacture, sale, or use of any method, apparatus, or productcovered by letters patent. Neither should anything contained in the publicat
5、ion be construed asinsuring anyone against liability for infringement of letters patent.All rights reserved. No part of this work may be reproduced, stored in a retrieval system, ortransmitted by any means, electronic, mechanical, photocopying, recording, or otherwise,without prior written permissio
6、n from the publisher. Contact the Publisher,API Publishing Services, 1220 L Street, N.W., Washington, D.C. 20005.Copyright 2001 American Petroleum InstituteTable of Contents1.0 INTRODUCTION . 52.0 NOMENCLATURE AND PARAMETERS OF INTEREST. 63.0 FLUID PROPERTIES. 133.1 Sample Collection 133.2 Density (
7、or ) 133.3 Viscosity (om ) 153.4 Surface Tension and Interfacial Tension (aos ,ows , and aws ) 154.0 POROUS MEDIA PROPERTIES LABORATORY-SCALE. 174.1 Sample Collection 174.2 Core Preservation (Field) 194.3 Core Screening and Preparation (Laboratory) . 204.4 Porosity (f ) 214.5 Permeability ( k ) 214.
8、6 Capillary Pressure vs. Saturation (cP vs.S ) . 234.7 Relative Permeability vs. Saturation (rk vs. S ) 244.8 Water and Product Saturation ( Swvs. So). 264.9 Determination of Brooks-Corey Model Parameters (l , dP , and wrS ) . 284.10 Determination of van Genuchten Parameters (rwS ,M, and a ). 295.0
9、POROUS MEDIA PROPERTIES FIELD-SCALE. 315.1 Baildown Tests. 315.2 Production Tests 32Theim Solution . 32Decline Curve Analysis 346.0 REPORTING 367.0 REFERENCES . 37APPENDIX A SHORT ABSTRACTS OF RELEVANT ASTM METHODS . 40APPENDIX B DERIVATION OF METHODS FOR ESTIMATING RELATIVE PERMEABILITY, AVERAGECON
10、DUCTIVITY TO OIL, AND TRANSMISSIVITY TO OIL FROM PRODUCTION DATA. 61APPENDIX C DERIVATION OF DECLINE CURVE METHOD. 64List of FiguresFIGURE 1 GENERAL CONCEPTUAL MODEL . 7FIGURE 2 HYDROSTATIC PRESSURE IN AIR, PRODUCT, AND AQUEOUS PHASES (AFTER FARR ET AL. 1990) . 8FIGURE 3 CAPILLARY PRESSURE - SATURAT
11、ION RELATIONSHIP FOR TWO-FLUID SYSTEM IN POROUS MEDIA. 92FIGURE 4 TYPICAL RELATIONSHIP BETWEEN RELATIVE PERMEABILITY AND FLUID SATURATIONFOR A TWO PHASE SYSTEM UNDER DRAINAGE. 10FIGURE 5 CAPILLARY RISE AS FUNCTION OF HYDRAULIC CONDUCTIVITY (AFTER MCWHORTER, 1996) 19FIGURE 6 GRAPHIC FORMAT FOR ANALYS
12、IS OF BROOKS-COREY PARAMETERS USING EFFECTIVESATURATION VERSUS CAPILLARY HEAD DATA (DATA FROM BROOKS AND COREY 1964,FINE SAND). 28FIGURE 7 GRAPHIC FORMAT FOR ANALYSIS OF BROOKS-COREY PARAMETERS USING RELATIVEPERMEABILITY SATURATION VERSUS CAPILLARY HEAD DATA (DATA FROM BROOKS ANDCOREY 1964, FINE SAN
13、D) 29FIGURE 8 GRAPHIC FORMAT OF ANALYSIS FOR VAN GENUCHTEN PARAMETERS USING LOG CAPILLARYPRESSURE VS. SATURATION DATA (DATA FROM BROOKS AND COREY 1964, FINE SAND). 30FIGURE 9 DUAL PHASE RECOVERY WELL PRODUCTION DATA . 33FIGURE 10 TRANSMISSIVITY TO PRODUCTS AS A FUNCTION OF TIME DEVELOPED USING WELLP
14、RODUCTION DATA FROM FIGURE 9 AND EQUATION (18) 34FIGURE 11 GRAPHICAL FORMAT FOR DECLINE CURVE ANALYSIS. 35List of TablesTABLE 1 PRODUCT DENSITY METHODS (or ) . 14TABLE 2 VISCOSITY METHODS (om ) 15TABLE 3 SURFACE TENSION AND INTERFACIAL TENSION METHODS (aos AND ows ) 16TABLE 4 POROSITY METHODS (f). 2
15、1TABLE 5 PERMEABILITY METHODS ( k ) 22TABLE 6 METHODS FOR CAPILLARY PRESSURE AS A FUNCTION OF SATURATION (cP VS. S ) 23TABLE 7 METHODS FOR RELATIVE PERMEABILITY AS A FUNCTION OF SATURATION (rkVS. S ) 25TABLE 8 WATER AND PRODUCT SATURATION METHODS (wS AND oS ) . 27TABLE 9 BAILDOWN TEST METHODS FOR ES
16、TIMATION OF PRODUCT TRANSMISSIVITY (FIELD-SCALE oT ) . 323AcknowledgmentsAPI STAFF CONTACTHarley Hopkins, Regulatory and Scientific Affairs DepartmentMEMBERS OF THE SOIL AND GROUNDWATER TECHNICAL TASK FORCEMEMBERS OF THE GW-90 PROJECT TEAM:Ravi Kolhatkar (Project Team Leader), BP AmocoGeorge DeVaull
17、, Equilon Enterprises LLCTom Henson, ExxonMobil CorporationJim Higinbotham, ExxonMobil CorporationDan Irvin, ConocoVic Kremesec, BP AmocoMark Lyverse, ChevronAPI acknowledges the following individuals for their contributions to this manual:G. D. Beckett, Aqui-Ver, Inc.Randall Charbeneau, University
18、of Texas at AustinArt Corey, Professor Emeritus, Colorado State UniversityLarry Kunkel, PTS Laboratories, Inc.David McWhorter, Professor Emeritus, Colorado State UniversityGary Moore, ERMMalcolm Pitts, Surtek, Inc.451.0 IntroductionThis manual describes methods used to obtain input parameters for mo
19、dels that evaluate themobility and potential recovery of petroleum liquids in unconsolidated granular porous media.These models are valuable tools for improving system design because, unfortunately, thepresence of petroleum liquids in a well is not itself a reliable indicator of the feasibility of f
20、ree-product recovery or the need to continue recovery operations.The feasibility and appropriate endpoint for free-product recovery can be addressed byevaluating the mobility of product in the sediment in which it is encountered. If the mobility ofproduct is high, there is a potential for future adv
21、erse product migration. In addition, it is likelythat properly designed recovery systems can effectively deplete a significant fraction of themobile product. Conversely, if the mobility of the product is low, the risk associated with futuremigration is low, and efforts to deplete mobile product will
22、 be ineffective.The intent of this document is to provide a reference for parties needing methods fordetermining inputs to product mobility, and volume models. The need for such data (inparticular at large sites such as refineries) has increased dramatically in recent years. In largepart this has be
23、en driven by broader use of multiphase flow models (e.g., Parker et al., 1994)and spreadsheet tools for analysis of product mobility (e.g., Charbeneau et al., 1999).Secondarily, it is recognized that for small sites the resources needed to conduct site specificmobility investigations may not be avai
24、lable. As such, it would be useful to generate a database of study results (obtained using consistent methods) that can be used at these sites.Standardization of methods is the ideal; unfortunately, it may not be possible in all cases. Anumber of factors frustrate rigid standardization. First, signi
25、ficant differences exist betweensites. A direct consequence is that the best methods for many analyses are different fordifferent sites. Secondly, only a few specialized laboratories conduct a number of the analyses(e.g., capillary pressure vs. saturation and relative permeability vs. saturation). T
26、he equipmentand methods used by these laboratories are highly specialized and frequently different. Assuch, it may not be possible to have all sites conduct measurements using a single method.Reflecting these challenges, this document provides options as opposed to rigid standards.The first section
27、introduces nomenclature and parameters of concern. Individuals familiar withmultiphase flow in porous media can skip this section. The second section addressesdetermination of fluid properties. The third section describes methods for analysis of porousmedia properties at a laboratory (column) scale.
28、 The fourth section addresses measurement ofporous media properties at a field scale. Lastly, suggestions for reporting results are presented.Throughout this document practices are described that involve the handling of potentiallyhazardous materials. This document does not address health, safety, a
29、nd regulatorycompliance issues. It is the responsibility of the user of this document to establish appropriatehealth and safety practices and to comply with relevant regulations.62.0 Nomenclature and Parameters of InterestA general conceptual model for petroleum hydrocarbon in granular porous media
30、is presented inFigure 1. In this example, a surface release of product has percolated through the unsaturatedzone. Below the capillary fringe an interval has formed in which product occurs as a continuousnon-wetting phase in the porous media. The term non-wetting reflects product occupying thelarges
31、t pore space and not directly contacting the porous media. The porous media issurrounded by a continuous water phase referred to as the wetting phase. Immediately abovethe capillary fringe, product forms a continuous intermediate wetting phase between the water(wetting phase) and the air (non-wettin
32、g phase). The critical feature to recognize is that two orthree separate fluid phases (including product) coexist in the pore space where product ispresent.Product that forms a continuous phase within the porous media is referred to as potentiallymobile product or mobile product. The qualifier “pote
33、ntially” is included because movementis contingent on the presence of a driving force. Product that is not present as a continuousphase is referred to as residual or immobile product. A significant feature of residual productis that it is typically immobile under the typical range of driving forces
34、associated with natural orinduced groundwater flow.The volumetric flux of product oq (L3/L2-T) at any point in the continuous product interval can bedescribed as:+-=dxdzgdxdPkkqoooroorm(1)where:k (L2)IntrinsicPermeabilitya property of the porous media that describes itscapacity to transmit a single
35、fluid that fullysaturates the porous media (saturation equal to 1).rok (Dimensionless)RelativePermeability toProducta ratio of permeability to product at a poresaturation less than 1 to the permeability at a poresaturation of 1. This describes reducedpermeability associated with product occupyingonl
36、y a fraction of the total pore space.om (M/LT)Dynamic Viscositya measure of a fluids resistance to shear.oP (F/L2)Pressureforce per unit area in the product phase in theproduct or oil.x(L)Distancein the direction of flow.or (M/L3)Densitymass per unit volume of oil.g(L/T2)GravitationalConstantacceler
37、ation imposed by gravity.z (L)Elevationposition above a given datum.(Note: L = length, M = mass, T= time, F= force)7Continuous Product (Two Phase Zone)Entry PointDiscontinuousImmobile ResidualProduct (Two Phase Zone)ContinuousProduct(Three Phase Zone)PlumesFigure 1 General Conceptual ModelThe mobili
38、ty of the product is defined as:orookkMm= (2)Unfortunately, the fraction of pore space filled with product (So), and consequently the relativepermeability to product (kro), changes with position. As such, mobility (Mo) is a function ofposition within the interval of continuous product. Variation in
39、product saturation (So) reflectslocally varying differences in pressure between the non-wetting and wetting phase pressures.This difference is defined as capillary pressure (F/L2)wnwcPPP -= (3)8Figure 2 illustrates pressure in the air, product, and water phases as a function of verticalposition unde
40、r the condition of no vertical flow. Recalling that pressure is linearly proportional tofluid density ( ghP r= ): Pressure in the air phase is essentially constant over the interval of concern due to the smalldensity of air. With depth, pressure increases fastest in the water phase since water has t
41、he greatestdensity. As the product is less dense than water, pressure increases more slowly with depth in theproduct than in the water,Gauge Pressure0 +-Continuous Non-wettingLNAPL in (Two Phase Zone,(Sw, So 0,Sg = 0)Continuous Wetting LNAPL (Three Phase Zone(Sg, Sw, So 0)Figure 2 Hydrostatic pressu
42、re in air, product, and aqueous phases(after Farr et al., 1990, ao = air-oil, form. = formation, ow = oil-water,well = well, aow = air-oil-water, a = air, w = water, o = oil).Building on the conditions defined in Figure 2, one can calculate both the volume and mobility ofthe continuous product prese
43、nt in the formation. Following Farr et al. (1990) and Lenhardt andParker (1990), this process begins by using fluid levels in wells to characterize static pressuresin the air, product, and aqueous phases (see Figure 2). Capillary pressures can be determinedfrom the static pressures. Next, either the
44、 Brooks-Corey (1964) or van Genuchten (1980)models are used to estimate product saturation and relative permeability as a function ofcapillary pressure. These computations can be readily conducted using the spreadsheet modelprovided by Charbeneau et al. (1999).z)( hDzgPowwellww+-= r)( TDzgPowwelloo+
45、-= r0=aPowwellDhTMonitoring wellProduct in wellaoformD.aowformD.owformD.9As an introduction to the remaining parameters of interest, the following describes the Brooks-Corey and van Genuchten models. Both of these models are algebraic equations used to fitcapillary pressure versus saturation data ob
46、tained from laboratory studies. For simplicity, thedefinition of physical parameters employed in describing both the models follows that used inBrooks and Corey (1964). Fitting parameters follow the definition presented in Brooks andCorey (1964) and van Genuchten (1980).A typical capillary pressure-
47、saturation relationship is presented in Figure 3. Procedures used toestimate fitting parameters from the capillary pressure data are described in Corey and Brooks(1999) and van Genuchten (1980). Alternatively, model parameters can be obtained by fittingthe models to relative permeability versus satu
48、ration data obtained from laboratory studies. Atypical relative permeability-saturation relationship is presented in Figure 4.So100% 0%100%0%SwPc0PdMain Drainage CurveMain Wetting(Imbibition) CurveSmSwrFigure 3 Capillary pressure - saturation relationship for two-fluid system in porous media10100% 0
49、%100%0%RelativePermeability01Relative permeabilityto wetting fluidRelative permeabilityto non-wetting fluidSoSwSwrSmFigure 4 Typical relationship between relative permeabilityand fluid saturation for a two-phase system under drainage.The Brooks-Corey model is described in Equations (4) through (6).l=-=cdwrwrwePPSSSS1for dcPP (4)-=+ll 221111wrwrwwrwrwroSSSSSSk (5)ll321+-=wrwrwrwSSSk(6)11where:eS (Dimensionless)Effective WettingPhase Saturationwetting phase saturation as defined in (4)
