1、API PUBL*4633 95 0732270 0549870 840 Em American Petroleum Institute Barium in Produced Water: Fate and Effects in the Marine Environment Health and Environmental Sciences Department Publication Number 4633 September 1995 Barium in Produced Water: Fate and Effects in the Marine Environment Health an
2、d Environmental Sciences Department API PUBLICATION NUMBER 4633 PREPARED UNDER CONTRACT BY: JERRY M. NEFF AND THEODOR c. SAUER, JR. ARTHUR D. LITTLE, INC. ACORN PARK CAMBRIDGE, MA 02140 APRIL 1995 American Petroleum Institute FOREWORD API PUBLICATIONS NECESSARILY ADDRESS PROBLEMS OF A GENERAL NATURE
3、. WITH RESPECT TO PARTICULAR CIRCUMSTANCES, LOCAL, STATE, AND FEDERAL LAWS AND REGULATIONS SHOULD BE REVIEWED. API IS NOT UNDERTAKING TO MEET THE DUTIES OF EMPLOYERS, MANUFAC- TURERS, OR SUPPLIERS TO WARN AND PROPERLY TRAIN AND EQUIP THEIR EMPLOYEES, AND OTHERS EXPOSED, CONCERNING HEALTH AND SAFETY
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5、PATENT. NEITHER SHOULD ANYTHING CONTAINED IN ITY FOR INFRINGEMENT OF LETERS PAmNT. THE PUBLICATION BE CONSTRUED AS INSURING ANYONE AGAINST LIABIL- API PUBLx4633 95 O732290 05Y2 bL3 Copyright O 1995 American Petroleum Institute i ACKNOWLEDGMENTS THE FOLLOWING PEOPLE ARE RECOGNIZED FOR THEIR CONTRIBUT
6、IONS OF TIME AND EXPERTISE DURING THIS STUDY AND IN THE PREPARATION OF THIS REPORT API STAFF CONTACT Alexis E. Steen, Health and Environmental Sciences Department A Joseph P. Smith, Chairperson, Exxon Production Research Company Kris Bansai, Conoco, Inc. Lewis M. Cook, Chevron Research and Technolog
7、y Company Philip B. Dom, Shell Development Company Jerry E Hall, Texaco Research Kim Petten, Amoco Corporation James P. Ray, Shell Oil Company Lawrence A. Reitsema, Marathon Oil Company Gary Rausina, Chevron Corporation Carlos Simon, Texaco, Inc. PREPARED BY Jerry Neff*, Arthur D. Little, Inc. Theod
8、or C. Sauer, Jr.*, Arthur D. Little, Inc. * No longer with this organization. iii API PUBL*4633 95 W 0732290 0549894 496 1 3 . BARIUM IN PRODUCED WATER AND NATURAL WATERS . 3-1 TABLE OF CONTENTS Section Paae EXECUTIVESUMMARY . ES-I 1 . INTRODUCTION . 1-1 2 . PHYSICAL CHEMICAL PROPERTIES OF BARIUM 2-
9、1 BARIUM IN PRODUCED WATER . 3-1 BARIUM IN SEA WATER . 3-8 RIVERINE INPUT OF BARIUM 3-12 4 . PRECIPITATION OF BARIUM DURING MIXING OF PRODUCED WATER ANDSEAWATER . 4-1 ACTIVITY OF BARIUM AND SULFATE IN PRODUCED WATER AND SEA WATER . 4-1 BEHAVIOR OF BARIUM DURING MIXING OF PRODUCED WATER WITH SEA WATE
10、R 4-6 5 . TOXICITY OF BARIUM 5-1 TOXICITY TO MARINE ORGANISMS 5-1 BIOACCUMULATION OF BARIUM BY MARINE ORGANISMS 5-6 TOXICITY TO FRESHWATER PLANTS AND ANIMALS 5-7 TOXICITY TO HUMANS . 5-8 REFERENCES R-I LIST OF FIGURES Fiaure Pase 3-1. The relationship between the concentrations of barium and sulfate
11、 in produced waters from different sources. The solid line is the approximate solubility product for barite at 100C. NS, North Sea; GOM, Gulf of Mexico; IL, Illinois; WY, Wyoming; NM, New Mexico; PG, Persian Gulf 3-6 Variation in dissolved barium concentrations as a function of chlorosity (concentra
12、tion of total inorganic halides other than fluoride per liter of seawater at a given temperature) for waters of the Mississippi River estuary, October, 1972 (open circles) and Louisiana coastal waters, April, 1 973 (solid circles). Solid lines are calculated ion exchange curves for concentrations of
13、 adsorbed barium. The dashed line is the theoretical barite saturation curve. From Chan and Hanor (1 982) 3-1 6 3-2. LIST OF TABLES Table Paae 2-1. 3-1. Physical/Chemical Properties of the Alkaline Earth Elements (Group IIA). From Snavely (1 989). . 2-1 Estimated Average Volumes in Millions of Liter
14、s/Day (Millions of BarreWDay in Parentheses) of Treated Produced Water Discharged to Coastal and Offshore Waters of the Gulf of Mexico, California, Cook Inlet, Alaska, the North Sea, and Australia 3-1 Typical concentration ranges of several classes of organic compounds and inorganic ions in produced
15、 water. Concentrations are in pg/L (Parts per Billion). Data are from Kharaka et a/., (1 978), Grahl-Nielsen (1 987), McGowan and Surdam (1 9881, Boesch et ai., (1 989a,b), Macpherson (1 989), Barth (1 991), Stueber and Walter (1 991 1, Jacobs et a/.l (1 992), Neff et a/.l (1 992), Stephenson (1 991
16、, 1992), and Tibbetts et a/., (1 992) . 3-3 3-2. API PUBL*4633 95 W 0732290 0549896 2b9 LIST OF TABLES (Continued) Table Paae 3-3. Concentrations of dissolved barium in offshore surface waters of the oceans. All concentrations are in pg/L . . . . . . . . 3-10 Predicted speciation of acetate, sulfate
17、, and alkaline earth elements in a typical saline (1 .O M NaCI) produced water at 125C. From Shock and Koretsky (1993) . . . . . . . . . . . . . . . 4-4 Barium Concentrations (pg/L) and Toxicity (EC,: Percent Produced Water Causing a 50 Percent Reduction in Shell Growth in Mussel Larvae) of Produced
18、 Water Fractions from Southern California. See Text for an Explanation of the Produced Water Fractions. From Higashi et a/., (1 992) . . . . . . . 5-3 4-1. 5-1. API PUBL*4633 95 I 0732290 0549897 IT5 EXECUTIVE SUMMARY This review provides a summary of what is currently known about the physical/chemi
19、cal behavior of barium in produced water and in the ocean and discusses the factors that may influence the rate of precipitation of barium as barite. The toxicity of barium to marine and freshwater organisms and humans also is discussed in relation to the concentrations and forms in which barium may
20、 occur in the marine and aquatic environment. The concentration of dissolved barium in oil weil produced water ranges from less than 100 to more than 2,000,000 pg/L (parts per billion). The concentration of dissolved barium in the ocean is in the range of 4 to about 20 pg/L and is controlled by the
21、high concentration of sulfate in sea water. Barium sulfate (barite) has a low aqueous solubility, reflected by its molal solubility product of approximately 1.05X1 O- at 25C. The saturation concentration of barium in equilibrium with barite in sea water is approximately 37 pg/L. Consequently, it is
22、expected that when produced water containing a high concentration of dissolved barium is discharged to the ocean, the barium will precipitate rapidly as barite. However, organic acid anions, sometimes present in produced water at concentrations as high as 10,000,000 pg/L, may complex with barium and
23、 slow its precipitation upon mixing of produced water with seawater. Barium concentrations in produced water are roughly inversely proportional to concentrations of sulfate, indicating that the barium is in equilibrium with barite in the formation. If saline water is injected into the fossil fuel re
24、servoir to enhance secondary production and some of the injection water mixes with the formation water, the concentration of sulfate in the produced water may cause super- saturation with respect to barite. ES- 1 API PUBLU4633 95 a 0732290 0549848 031 The rate of precipitation of barium from produce
25、d water in the ocean has not been measured directly. Upon discharge of produced water to the ocean, precipitation of barium as barite may be slow unless the produced waterlsea water mixture is several-fold supersaturated with respect to free, ionic Ba+ and SO,*. After initiai barite crystal nuclei a
26、re formed, precipitation may be rapid. Produced water containing more than about 1 O0 pg/L dissolved barium will produce, upon dis- charge, a produced water/sea water mixture that is supersaturated with respect to barite in the presence of a typical concentration of sulfate in sea water (0.028 M). A
27、 typical Gulf of Mexico produced water contains about 50,000 pg/L (0.000364 M) dissolved barium; Gulf of Mexico sea water contains about 0.029 M sulfate. Assuming an apparent activity coefficient of 0.2 for barium in produced water and an apparent activity coefficient of 0.1 7 for sulfate in sea wat
28、er, a 99:l sea water:produced water mixture is about 30 times supersaturated with respect to barite. The rate of precipitation of barite from such a highly supersaturated mixture is diffusion-rate limited, so precipitation will be very rapid in a well-mixed receiving water environment. If a scale in
29、hibitor is used in the production stream or produced water treatment system, it may appear in the treated produced water that is discharged to the ocean and may inhibit the initiation or slow the rate of precipitation of barium. In addition, organic acid anions, sometimes present at high concentrati
30、ons in produced water, may complex with dissolved barium, reducing its apparent activity coefficient and reducing the rate of barium precipitation in the ocean. Solid barite and dissolved barium in sea water are not very toxic to marine and freshwater organisms. In sea water, toxic concentrations of
31、 barium ion are in excess of barium solubility and are only observed in bioassays with embryos and larvae of marine invertebrates during exposure to fine suspended barite particles or ES-2 barium-organic acid complexes. In fresh water, barium solubility is controlled by sulfate; barium can only reac
32、h toxic concentrations if the water contains a low concentration of sulfate. Barium in drinking water has a low toxicity to humans. Thus, dissolved barium at concentrations that are stable in the sea water and fresh water is not likely to be toxic to marine, freshwater, or terrestrial organisms. ES-
33、3 API PUBLm4633 95 M 0732290 0549900 51T Section 1 INTRODUCTION The two most important (in terms of volumes generated and regulatory concern) waste products sometimes permitted for discharge from offshore exploration and production platforms are drilling fluids and produced water (Neff et a/., 1987)
34、. Both wastes are complex mixtures of water-soluble and insoluble, inorganic and organic chemicals in water. Barium is one of the most abundant inorganic chemicals (other than the dominant seawater ions) in both drilling fluids and produced water from some locations. Barium is added intentionally, a
35、s the mineral barium sulfate (BaSO,), to most drilling fluids as a weighting agent because of its high density and low aqueous solubility. Barium is a natural ingredient of produced water. Studies of barite in drilling fluids generally have shown that this dense, insoluble mineral is virtually nonto
36、xic to marine organisms (National Research Council, 1 983). The low toxicity of barite to marine organisms usually is attributed to its low solubility in seawater (high in sulfate). However, most of the barium in produced water is present in a dissolved form. Concern has been expressed and some circ
37、umstantial evidence published (Higashi et a/., 1 992; Raimondi and Schmitt, 1992; Cherr and Fan, 1993) that dissolved or colloidal barium discharged to the sea in produced water may be toxic to sensitive life stages of marine organisms. The kinetics of precipitation of soluble barium as barite upon
38、mixing of produced water with sea water is not understood; therefore, the persistence of dissolved barium in a diluting produced water plume at concentrations significantly higher than natural background is not known. The objectives of this review are to summarize the scientific literature on the co
39、ncentrations and behavior of barium in produced water and its behavior and 1-1 API PUBLS4633 95 I 0732290 05Y99OL Y56 I toxicity upon discharge to saline receiving waters. The concentrations and chemical speciation of barium in natural marine and fresh water and in produced water are discussed first
40、. This section will include a discussion of the effects of various physical and chemical parameters on the solubility product of barite and the solubility of barium. Our current understanding of the physical chemistry of precipitation of barium upon mixing of produced water with sea water is describ
41、ed next. There is a discussion of the factors that may affect the rate of barium precipitation following discharge of produced water to the ocean. Finally, the toxicity of barium and barium sulfate to freshwater and marine organisms and humans is discussed in relation to the predicted precipitation
42、kinetics of barium plus sulfate in the receiving water environment. 1-2 API PUBL*4633 95 0732290 05Lt902 372 = Section 2 PHYSICAL CHEMICAL PROPERTIES OF BARIUM Barium is an alkaline earth element (Group IIA of the periodic table). There are four alkaline earths with lower molecular weights than bari
43、um. These are beryllium (MW 9.01 ), magnesium (MW 24.321, calcium (MW 40.08), and strontium (MW 87.63). There is one alkaline earth element with a higher molecular weight, radium (MW 226.05) (Table 2-1). Barium, with a molecular weight of 137.36, shares many physical/chemical properties with the oth
44、er alkaline earth elements. Beryllium, with a charge density more than twice that of the other Group IIA elements, has different chemical properties than the other elements in the group. Table 2-1 . Physical/Chemical Properties of the Alkaline Earth Elements (Group IIA). From Snavely (1 989). Ion Mo
45、lecular Crystal Hydrated Charge Ksp MISOJ Weight Radius () Radius (A) Density 25C Be+ 9.01 0.31 4.59 6.45 - Mg+ 24.32 0.65 4.28 3.01 -_ Ca+ 40.08 0.99 4.12 2.02 3.75X1 Sr+ 87.63 1.13 4.12 1.77 3.42X1 O- Ba+ 137.36 1.35 4.04 1.48 I .05X1 O- Ra+ 226.05 1.52 3.98 1.32 4.30X 1 O- Like all the alkaline e
46、arth elements, barium readily looses its outer two electrons, forming the divalent cation (Ba+2). Barium is a stronger reducing agent and more readily forms bases than the other alkaline earths, except radium. Because barium has a relatively low ionic potential, it goes into aqueous solution as the
47、hydrated ion. Adsorption of ionic barium to clay particles and organic matter is stronger 2- 1 API PUBLg4633 95 W 0732290 0549903 229 I than adsorption of lower molecular alkaline weight earths, because of its smaller hydrated ionic radius (Lagas et a/., 1984). All the alkaline earth elements readil
48、y form oxides, hydroxides, carbonates, and sulfates. However, because its crystal radius (1.35 ) is larger than that of lower molecular weight alkaline earths, Ba+2 does not readily substitute for other alkaline earths in various crystal matrices, such as calcium carbonate. Barium is incorporated mo
49、re readily into precipitating calcite than aragonite (Kitano et a/. , 1971 ); also tends to inhibit incorporation of strontium into these two crystal forms of calcium carbonate (Morse and Bender, 1990). The most abundant naturally occurring barium minerals are barite (BaSO,: also called barytes), witherite (BaCOJ, barytoangelsite (Ba,PbSO,), and bromlite (CaBaCO,I) (Pilkey, 1 972). Barium, like the other alkaline earth elements, forms soluble salts with chloride, bromide, and nitrate, and relatively insoluble salts with sulfate, carbonate, phosphate, and acid
