1、 Modeling Study of Produced Water Release Scenarios API Publication Number 4734 January 2005 Modeling Study of Produced Water Release Scenarios Regulatory Analysis and Scientific Affairs Department API Publication Number 4734 January 2005 PREPARED UNDER CONTRACT BY: Jan M. H. Hendrickx, Department o
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5、able requirements of that standard. API does not represent, warrant, or guarantee that such products do in fact conform to the applicable API standard. All rights reserved. No part of this work may be reproduced, stored in a retrieval system, or transmitted by any means, electronic, mechanical, phot
6、ocopying, recording, or otherwise, without prior written permission from the publisher. Contact the Publisher, API Publishing Services, 1220 L Street, N.W., Washington, D.C. 20005. Copyright 2005 American Petroleum Institute FOREWORD Nothing contained in any API publication is to be construed as gra
7、nting any right, by implication or otherwise, for the manufacture, sale, or use of any method, apparatus, or product covered by letters patent. Neither should anything contained in the publication be construed as insuring anyone against liability for infringement of letters patent. Suggested revisio
8、ns are invited and should be submitted to the Director of Regulatory Analysis and Scientific Affairs, API, 1220 L Street, NW, Washington, DC 20005. ACKNOWLEDGMENTS API would like to acknowledge the following people for their contributions of time and expertise during this study and in the preparatio
9、n of this report: API STAFF CONTACTS Harley Hopkins, Regulatory Analysis and Scientific Affairs Department (RASA) Terry Twyman, Upstream MEMBERS OF THE PRODUCTION WASTE ISSUES GROUP (PWIG) AND THE PWIG BRINE WORK GROUP: Evan Sedlock, ChevronTexaco Energy Technology Company; PWIG Chairman Jeffrey Ada
10、ms, BP America, Inc Mickey Carter, ConocoPhillips Corporation George Deeley, Shell Global Solutions (US) Inc. Neal Goates, ConocoPhillips Corporation Jill Kerr, Exxon Mobil Corporation Rosemary Martinez, BP America Greg Minnery, ChevronTexaco Sam Small, Amarada Hess Corporation Mike Starrett, Oxy Pe
11、rmian Appreciation is extended to Carolyn Haynes of Rice Operating Company for providing funding for the field verification of the modeling. Modeling Study of Produced Water Release Scenarios i TABLE OF CONTENTS Table of Contents i Executive Summary. v Technical Highlights viii 1.0 Introduction . 1
12、1.1Project Overview. 1 1.1.1 Research Objective 1 1.1.2 Project Organization . 1 1.1.3 Scope of Modeling . 1 1.2 Background 3 1.2.1 Fulfilling an Industry Need. 3 1.2.2 Potential Impacts of a Release .4 1.2.3 Common Soil Restoration Programs .4 1.2.4 Restoration of Chloride in Ground Water . 5 2.0 F
13、actors Influencing the Migration of Chloride 6 2.1 Vadose Zone Factors6 2.1.1 Vadose Zone Texture.6 2.1.2 Water Content in the Vadose Zone 6 2.1.3 Dispersion Length of Chloride in the Vadose Zone 7 2.1.4 Depth to Ground Water or Vadose Zone Thickness . 7 2.2 Climate.8 2.3 Brine Release Factors8 2.3.
14、1 Chloride Concentration of Release 8 2.3.2 Release Volume and Total Mass8 2.3.3 Height of Spill.8 2.4 Groundwater Characteristics9 2.4.1 Ground Water Flux.9 2.4.2 Aquifer Thickness.9 2.4.3 Aquifer Ambient Chloride Concentration.9 2.5 Heterogeneity 9 2.6 Repeated Releases. 10 3.0 Modeling Approach 1
15、1 3.1 Vadose Zone Model: HYDRUS-1D 11 3.1.1 Model Overview11 3.1.2 Applicability of HYDRUS-1D for Produced Water Releases 12 3.2 Saturated Zone Model: Mixing Model and MODFLOW. 12 3.3 Data Sources 16 3.3.1 Soil Data 16 3.3.2 Climate Data . 16 4.0 Sensitivity Analysis of Factors Determining Brine Fat
16、e 17 4.1 Purpose17 4.2 Modeling Specifics .17 4.2.1 Vadose Zone Factors17 4.2.2 Aquifer Factors . 19 4.2.3 Brine Release Factors.20 4.3 Simulation Responses.22 4.4 Statistical Analysis of the Responses at a Monitoring Well22 4.4.1 Maximum Chloride Concentration23 4.4.2 Arrival Time of Maximum Chlori
17、de Concentration . 27 5.0 Initial Vertical Distribution of Chloride (First Year). 29 5.1 Purpose.29 5.2 Modeling Methodology .29 5.3 Analysis and Data Presentation30 API Publication 4734 ii 6.0 Heterogeneity 42 6.1 Purpose.42 6.2 Modeling Methodology and Input .42 6.3 Analysis and Data Representatio
18、n .42 7.0 Vertical Chloride Distribution Over Thirty Years 46 7.1 Purpose.46 7.2 Modeling Methodology .46 7.3 Analysis and Data Presentation46 8.0 Repeated Releases . 54 8.1 Purpose 54 8.2 Modeling Methodology and Input .54 8.3 Analysis and Data Presentation . 55 9.0 Soil Restoration . 58 9.1 Purpos
19、e.58 9.2 Modeling Methodology and Input .58 9.3 Data Analysis and Presentation .58 10.0 Effects of Vegetation 63 10.1 Purpose.63 10.2 Modeling Methodology and Input63 10.3 Data Analysis and Presentation63 11.0 Understanding the Role of Each Factor 70 11.1 Produced Water Release Characteristics 70 11
20、.2 Vadose Zone Characteristics .70 11.3 Climate.71 11.4 Vegetation71 12.0 Verification of Model HYDRUS 1D for Prediction of Chloride Fate . 72 12.1 Purpose 72 12.2 Approach 72 12.3 Description of Sites and Boundary Locations . 73 12.4 HYDRUS 1D Simulations 73 12.4.1 Anode Beds (Sites L-21 and M-33).
21、 73 12.4.2 Junction Boxes (Sites EME P36-2 19S 3E and EME M-3-1A 21S 36E). 76 12.5 Data Analysis and Presentation . 76 References 79 Appendix A Results of homogenous and heterogeneous profiles . 81 Figures 1.1 Schematic of chloride movement from brine spill through the vadose zone towards monitoring
22、 well 3 2.1 Soil texture triangle used by the U.S Department of Agriculture. 7 3.1 Comparison between MODFLOW and the mixing model. Perturbations in the MODFLOW curve reflect the use of actual rainfall data. 15 4.1 Schematic of two possible brine release characteristics after a release of 100 barrel
23、s 21 4.2 The effect of nine brine release, vadose zone, and aquifer factors on the maximum chloride concentration in a down gradient monitoring well.24 4.3 Interaction effects between the factors soil, flux in aquifer, thickness of aquifer, and chloride load on the maximum chloride concentration in
24、a down gradient monitoring well .26 4.4 The effect of nine brine release, vadose zone, and aquifer factors on the time when the maximum chloride concentration arrives in a down gradient monitoring well 28 4.5 Interaction effects between the factors climate, soil, and ground water depth on the time w
25、hen the maximum chloride concentration arrives in a down gradient monitoring well 28 5.1 Sensitivity analysis of depth of maximum chloride concentration in the Weeks 1 and 2 . 37 5.2 Sensitivity analysis of depth of maximum chloride concentration in Weeks 3 and 4 .378 5.3 Sensitivity analysis of dep
26、th of maximum chloride concentration in weeks 5 and 50 39 5.4 Distribution of chloride concentration with depth in the arid climate.40 5.5 Distribution of chloride concentration with depth in the humid climate 41 7.1 Vertical chloride distribution in homogeneous clay profiles in arid and humid clima
27、tes 48 Modeling Study of Produced Water Release Scenarios iii 7.2 Vertical chloride distribution in homogeneous sand profiles in arid and humid climates .49 7.3 Vertical chloride distributions in heterogeneous profiles with 3, 10, and 20 m of accumulated clay layers in an arid climate 50 7.4 Vertica
28、l chloride distributions in heterogeneous profiles with 3, 10, and 20 m of accumulated clay layers in humid climates 51 8.1 Comparison of maximum well concentrations after one release and after three releases at one-year intervals in the humid and arid climates56 8.2 Breakthrough curves at the well
29、after one release and three releases at one-year and five-year intervals, respectively, through a homogeneous 30 m deep sand profile in the humid and arid climates 57 9.1 Chloride depth profiles in a 30 m deep sand vadose zone after a spill height of 2.5 cm with concentration 100,000 ppm with and wi
30、thout restoration by soil leaching during 45 days. Leaching starts on day 90 at a rate of 0.02 m/day60 9.2 Chloride depth profiles in a 30 m deep clay vadose zone after a spill height of 2.5 cm with concentration 100,000 ppm with and without restoration by soil leaching during 110 days Leaching star
31、ts on day 90 at a rate of 0.02 m/day . 61 9.3 Chloride concentrations in 3 m deep root zones with and without restoration by soil leaching in a sand and clay vadose zone after a spill height of 0.025 m with chloride concentration 100,000 ppm .62 10.1 Schematic of water and solute fluxes as well as c
32、hloride concentrations evaluated with HYDRUS1D and the mixing model under bare soil and vegetation .65 10.2 Vadose zone water flux and chloride concentration of the water entering into the shallow aquifer in a 30 m deep clay profile in Shreveport under bare soil and vegetation 66 10.3 Vadose zone ch
33、loride flux and chloride concentration in the well in a 30 m deep clay profile in Shreveport under bare soil and vegetation 67 12.1 Measured and simulated chloride profiles with depth under the anode beds M-33 and L-21 . 77 12.2 Measured and simulated chloride profiles with depth under the junction
34、boxes EME P36-2 19S 3E and EME M-3-1A-21S 36E78 Tables TH-1a Distribution of the maximum chloride concentrations simulated in a down gradient monitoring well.viii TH-1b Distributions of the maximum chloride concentrations for brine concentrations of 10,000 and 100,000 ppm after spills of 100 and 10,
35、000 barrels simulated in a down gradient monitoring well ix TH-2a Distribution of the maximum chloride concentrations detected in a down gradient monitoring well for all 384 heterogeneous profiles simulated These profiles were 10, 20, and 30 m deep xi TH-2b Distribution of the maximum chloride conce
36、ntrations for brine concentration 100,000 ppm after spills of 100 and 10,000 barrels at Hobbs and Shreveport detected in a down gradient monitoring well for 384 scenarios in heterogeneous profiles These profiles were 10, 20, and 30 m deep . xi 1-1 Project Organization 2 4-1 Vadose zone, aquifer, and
37、 brine release factors determining maximum chloride concentration arriving at a monitoring well down gradient of a brine release 18 4-2 Characteristics of brine release in this study . 21 4-3 Main effects of the vadose zone, aquifer, and brine release factors on the maximum chloride concentration ar
38、riving at the monitoring well Cmax, first sensitivity analyzes 24 4-4 Main effects and important interactions of the vadose zone, aquifer, and brine release factors on the maximum chloride concentration arriving at the monitoring well Cmax and the time of arrival of the maximum concentration Tmax, s
39、econd sensitivity analyzes . 25 4-5 Statistics of maximum chloride concentrations (ppm) determined in the sensitivity analysis 27 5-1 Input Parameters for HYDRUS1D Model for Analysis of Initial Vertical Brine Distribution.29 5-2.1 Depth of Penetration of chloride concentration 250 ppm; Humid Climate
40、, Depth of Ground Water Table = 3 m 31 5-2.2 Depth of penetration of chloride concentration 250 ppm; Humid Climate, Depth of Ground Water Table = 30 m32 API Publication 4734 iv 5-2.3 Depth of penetration of chloride concentration 250 ppm; Arid Climate, Depth of Ground Water Table = 3 m 33 5-2.4 Dept
41、h of penetration of chloride concentration 250 ppm; Arid Climate, Depth of Ground Water Table = 30m.34 5-3 Depth of Penetration of the Maximum Chloride Concentration 35 6-1 Inout Parameters for the Heterogeneous Profiles .44 6-2 Maximum Concentration at the Groundwater Table and in the Well 45 7-1 F
42、actors in the Vadose Zone Considered in the Simulations 46 7-2 Distribution of Chloride Over Time in Homogeneous Profiles 52 7-3 Distribution of Chloride Over Time in Heterogeneous Profiles . 53 8-1 Factors in the vadose zone considered in the simulations 54 9-1 Maximum chloride concentrations in a
43、30 m thick aquifer overlain by a 30 m thick sand vadose zone after a spill with chloride concentration 100,000 ppm 59 10-1 Comparison of maximum chloride concentrations and arrival times at the well under bare soil and vegetation.68 12-1 Characteristics of the four sites used for the verification of
44、 the HYDRUS1D model. 74 12-2 The hydrogeological characteristics of the four sites used for the HYDRUS1D verification. 75 A-1 Design matrix for the factors that affect chloride movement in the vadose zone and aquifer as well as two response variables in the monitoring well. Brine concentration 10,00
45、0 ppm .83 A-2 Design matrix for the factors that affect chloride movement in the vadose zone and aquifer as well as two response variables in the monitoring well. Brine concentration 100,000 ppm.98 A-3 Design matrix for heterogeneous profiles in Hobbs, as well as two response variables in the monito
46、ring well 113 A-4 Design matrix for heterogeneous profiles in Shreveport, as well as two response variables in the monitoring well 119 Modeling Study of Produced Water Release Scenarios v EXECUTIVE SUMMARY Project Goals This document provides a scientific basis for operators, regulators and landowne
47、rs to determine if assessment or remediation of produced water releases will provide a meaningful environmental benefit. The two principal research objectives of this study are (i) the identification of produced water release scenarios that have a potential to cause ground water quality impairment i
48、n homogeneous subsurface geologic profiles, and (ii) the prediction of chloride movement through the vadose zone1 for different release scenarios. Secondary objectives of the study included evaluation of the effect of heterogeneity on the migration of chloride through the vadose zone, the impact of
49、repeat releases and the effect on ground water quality of surface soil restoration by revegetation and soil leaching. This modeling study deals with sudden produced water releases of 100 to 10,000 barrels that infiltrate into the soil within a period of 1 day (sand soil) to 30 days (clay soil). Depending on the environmental conditions, the chloride molecules in the produced water may or may not reach the ground water. However, if produced water remains in the root zone, impacts to plants and soil fertility are possible. Release Scenarios Deemed Unlikely To Cause Ground Water Quality Impairm
