The flash-steam conversion cycle is most suitable for electric power production at the SSGF. However, large-scale development of the SSGF may require use of makeup water supplements to injected brine for a viable reservoir pressure maintenance program. Since steam condensate will probably be required to satisfy power plant cooling needs, local surface waters have been evaluated for their potential use as sources of injection makeup. It was found that direct injection of untreated makeup water is not feasible because of high suspended solids loading and potential incompatability problems. However, mixtures of ambient temperature makeup water and higher temperature (80 to 90/sup 0/C) brine effluent, in a 1:4 mass ratio, are potentially injectable following processing by reaction clarification and granular media filtration

Harrar, J.E.

Owen, L.B.

Raber, E.

UNT Digital Library

PREPRINT UCRL- 8301 1 ce Livermore Laboratory I USING SURFACE MATERS FOR SUPPLEMENTING INJECTION AT THE SALTON SEA GEOTHERMAL FIELD (SSGF), SOUTHERN CALIFORNIA s E l l e n  Raber, Lawrence B. Owen, and Jackson E. Harrar July 10, 1979 Geothermal Resources Counci 1 1979 Annual Meeting September 24- Reno, Nevada I I This is a preprint of a paper intended for publication in a journal or proceedings. Since changes may be made before publication, thls preprint is made available with the understanding that it will not be cited or reproduced without the permission of the author. t DISCLAIMER  This report was prepared as an account of work sponsored by an agency of the United States Government.  Neither the United States Government nor any agency Thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights.  Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.  The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. DISCLAIMER  Portions of this document may be illegible in electronic image products.  Images are produced from the best available original document.  -. 0 4 FOR SUPPLEMENT I NG INJECT I L FIELD (SSGF), SOUTHERN 'CALIFORNIA B. Owen, and Jack vennore Laboratory vennore, Cal l f o rn ia  94550 Previous work has b i l l t y  of condit ioning geothermal e f f luen ts  from the SSGF f o r  i n jec t i on  by a combined process consist lng of reac t io  l a r i f l c a t i o n  and granu- l a r  media filtratlon.P:5 We used a be ch- scale method developed by Quong e t  at.! t o  determine i f  reaction c l a r i f i c a t i o n  is a v iab le  condit ioning process f o r  mlxtures o f  ambient temperature makeup water and geothermal b r ine  a t  about 90°C. We also car r ied  out prel iminary core and f i l t e r  tests i n  conjunction w i th  the  operation, by Magma Power Co., o f  a p i l o t  pre- i n jec t i on  processing system t o  establ ish the i n j e c t a b i l i t y  of  conditioned mixtures o f  Salton Sea water and brine. The l n j e c t l v i t y  t es ts  ABSTRACT sh-steam conversi sui table f o r  e lec t r i c  power production a t  the  SSGF. However, large-scale development of the SSGF may requ're use Of makeup water supplments t o  in jected br ine fo r  a v iable reservoir  pressure maintenance program. Since steam condensate w i l l  probably be required t o  s a t i s f y  power p lan t  cooling needs, loca l  surface waters have been evaluated for t h e i r  po ten t ia l  use as sources o f  in jec t ion  makeup. We found t h a t  d i r e c t  i n jec t i on  o f  untreated makeup water i s  not feasible because o f  h igh suspended so l ids  loading and potent ia l  incompatabi l l ty problems. However, mixtures o f  amblent temperature makeup water and higher temperature (8 eff luent. i n  a 1:4 mass ra t io ,  I n jec t  able fo l lowing processing c l a r i f i c a t i o n  and granular medi INTRODUCTION ent and procedures des r i bed  by  wen3 and Tewhey et al. ECTION OF AMBIENT TEMPERATURE alysis of Salton Sea, New River, E MAKEUP WATERS and Alamo River water were determined and are ale u t i l i z a t i o n  provided i n  Table 1. I n  general, River water has about 8 times less dissolved su l fa te  than Salton Sea water. Use o f  River water f o r  In jec t ion  makeup w i l l  r esu l t  i n  a s ign i f i can t  reductlon i n  su l fa te  precipi tat ion.  However, the high par t i cu la te  loading i n  River water r e l a t i v e  t o  Salton Sea water can s i g n l f i c a n t l y  Increase the sludge processing requirements on a seasonal changes i n  f low r a t e  and pa r t i cu la te  loading could Cause differences i n  both the .physical and chemical propert ies o f  New and resources i n  Cali fornia's Imperial Val ley w i l l  necessitate a viable supply of cool ing water. However, i r r iga t ion 'waters  w i l l  probabl unavailable i n  the quant i t ies ult imate1 required t o  sa t is fy  power p lan t  cool ing The flash-steam conversion cycle o f fe rs  o f  clean cool ing water I n  the  form of s condens ate Condens ate us age, however, c l a r i f  f e r  processing system. Furthermore, t ha t  a s ign i f i can t  mass f r a c t l o n  o f  pro f l u i d s  can not be returned t o  the  produ reservoir. In the case o f  a t yp i ca l  do f l a s h  cycle operating a t  the Salton Sea Geothermal F i e l d  (SSGF), from 20 t o  25 perc o f  the productlon f l u i d  we l l  be l o s t  as vapor. Since reservoir  pressure maintenance may become resources, we have evaluated the f e a s i b i l i t y  o f  using loca l  surface waters fo n jec t ion  makeup. Within the Imperial Valley, there are three po ten t ia l  sources of  i n jec t i on  makeup water; the  New River, the Alamo River, and the Salton Sea. However, extensive diverslon o f  the waste irri- gation waters carr ied by  the New and Alamo TABLE 1 m1w WLm OF WIA urn hd') -a v i t a l  issue a t  sane Imperial Valley, geothermal lowS nW RIVER RIVER Wrmt SI* WTOn SEA' WTON SEh' . Raber e t  a l .  We f i r s t  evaluated Salton Sea water as a potent ia l  source o f  i n jec t i on  makeup. Sea water samples obtained o f f  Obsidian Butte (Table l) ,  were held a t  temperatures between 25 ad 90% f o r  periods o f  1 t o  7 days i n  nltrogen pressur- ized and sealed glass ampuoles. The sea water was se t t led  overnight and then decanted p r i o r  t o  use i n  heating experiments. Concentrations o f  suspended sol ids were obtained as a function of temperature and incubation time. Relat ive ease or d i f f i c u l t y  of f i l t r a t i o n  through membrane fil- ters  w i th  pore sizes ranging from 0.4 t o  5.0pm was also observed. Results o f  the sea water heating experiment are s m a r i z e d  i n  Table 2. Samples heated f o r  24 hours were a l l  d i f f i c u l t  t o  f i l t e r  regardless of  f i l t e r  pore size (0.4 t o  5.0pm) or  solut ion temperature. F i l t e r s  plugged a f te r  passage of 200 m l  or less o f  solution. Chemical i n te r -  action e f fec ts  between solutions and f i l t e r s  were not responsible f o r  f i l t r a t i o n  d i f f i c u l t i e s  because f i l t r a t e s  were highly f i l t e rab le .  One sample incubated a t  9OOC f o r  7 days was easy t o  f i l t e r .  These resul ts indicate tha t  f i n e  part iculates i n  Salton Sea water read i l y  plug even r e l a t i v e l y  coarse 5.0 pm pore s ize f i l t e r s .  Prolonged incubation a t  90% improves f i l t r a -  t i o n  properties of  sea water e i ther  by thermal deccinposi t i o n  o f  organic part iculates or changes i n  part iculate pa r t i c l e  s i t e  distr ibutions. Ambient temperature Salton Sea water contains 9.8 t 5 ppm suspended part iculates. Incubation o f  Salton Sea water a t  90% f o r  24 hours does not s ign i f i can t l y  a1 t e r  part iculate concentra- t ion. However, incubation a t  9OOC f o r  7 days does increase part iculates s l i g h t l y  t o  19 ppm. TABLE 2 SALTON SU WATER EATIff i  WPERIIIENlAL RESULTS .- EFNfAM 1NCUBATION IHCVBATIDN PARTICUUTE *FILTRATlOH SIZE (vu) ('0 (DAYS) (pPn-ntll(6) FILTER PORE TWERrmRE DURATION CDNCEWTRATIDN CHARACTERISTICS 0.4 25 1 6.5 DIFFICULT 0.4 50 1 11.3 DIR ICULT 0.4 75 1 4.5 DlRICULT 0.4 w 1 7.7 DIFFICULT 1.0 25 1 l2.3 DIFFICULT 1.0 25 1 15.8 DIFFICULT 1.0 w 7 19.0 WY 5.0 25 1 4.5 DIFFICULT DIFFICULl - FILTER PLUGSING AFTER P M 6 E  OF I 200 R OF SOLUTION. F i l t r a t i o n  properties o f  Salton Sea water, New River, and Alamo River are compared i n  Table 3. A l l  o f  the waters have extremely poor f i l- t r a t i o n  propert ies due t o  suspended part iculates. I n  addition, the high pH and dissolved carbonate and su l fa te  content (Table 1) o f  these waters suggests a s ign i f i can t  potent ia l  exists f o r  post i n jec t i on  prec ip i ta t ion  o f  sulfates and carbo- nates if injected waters reheat or mix w i th  typ ica l  geothermal brine. We concluded tha t  d i rec t  i n jec t i on  o f  makeup waters i s  not feasible. TABLE 3 -SALTai SEA 25.69 8.19 VERY P W R  (FILTER PLUGGED WEY RIVER u2.W 8.40 P W R  (FILTER PLUGGED AFTER M R l V E R  557.2 8.25 VERY POMI (FILTER PLu66ED *LO m FlLTRATlON SIPUATES DFICIENCI ATTAINABLE F, TYPICAL AnER 144 W bo) 2w M bo) AFTER 200 W QO) PRElWJECTlDN PROCESSlffi SWEUS CGNSISTMG OF REACTION C U R I F l t A T I a i  bND WUUR EDIA FILTRATION.  - . -&- Oi MAKEUP WATER - GEOTHERMAL B MI XING EXPERIMENTS Incubation tes ts  were carr jed out t o  establ ish nominal growth rates o f  suspended part iculates i n  1:4 mixtures (by weight) o f  1 pm pre f i l t e red  makeup water (Salton Sea, New River and Alamo River) and un f i l t e red  br ine e f f luen t  from the LLL t es t  s ta t ion  (Magmamax No. 1 well). Incubation was done a t  90% f o r  periods ranging from 15 minutes t o  30 days i n  nitrogen-pressur- ized and sealed glass ampoules. mixtures of Salton Sea water and br ine are s m a r i z e d  i n  Table 4. Samples were incubated a t  90°C f o r  24 hours and then f i l t e r e d  with 1.0 pm membrane f i l t e r s .  A l l  solut ions were easy t o  f i l t e r .  Normally, 'spent' br ine frm the LLL t e s t  s ta t ion  (Magamax # l  brine) produces between 300 and 350 ppm suspended sol ids a f t e r  1/2 hour incubation a t  90°C. Addit ion o f  Salton Sea water t o  br ine increased suspended sol ids by a fac to r  o f  a t  least  two. I n  the absence of excess dissolved sulfate, carbonate and oxygen, the d i l u t i n g  e f fec t  o f  a s imi la r  volume o f  water s ign i f i can t l y  reduces par t i cu la te  precipitat ion. Our prel iminary experiments u t i l i z i n g  1:4 Computer calculat ions assuming Sal ton Sea water of  ' t yp ica l '  composition are i n  excel lent agreem n t  w i th  resu l ts  o f  the reheating exper- iment.! The maximum concentration o f  part icu- lates a f te r  seven days incubation a t  90% was 19 ppm. The computer code predicted 30 t o  55 ppm t o t a l  carbonate sol ids varying i n  composition between ca l c i t e  (CaC03) and dolanite (CaMg (CO3)2). If Salton Sea water were p r e f i l -  tered a t  ambient temperature (25-35OC) p r io r  t o  reheating, no su l fa te  sol ids would precipi- t a te  u n t i l  the br ine was reheated t o  lOOOC. TnBLE 4 SALT SU WATER - BRIE RlXlllRE KHEAllNG EXPERILNTAL KSULTS AT WC -'IWCUgATION PARTICUUTE (WRS) (?PII/k/Kb) SOLUTION DURATION CONCENTRATION BRINE 0.5 300-350 230 612 BRIM PLUS DISTILLE9 WATER 24 BRIM PLUS SALTON SEA HATER 24 (4:i RIXTUE) (4:l R I r n R E  10 HOUR AT WC. PARTICWLTE CONCENTRATION RUCHES OUASI-BUILIBRIOFI AFTER Y - I Raber e t  a i .  Additional experimental results for  incu- bation of 1:4 mixtures of Salton Sea water-brine and river water-brine are sunnnarized i n  Figure 1. I t  is important t o  note that  mixtures of River water and brine at ta in  equilibrium most rapidly. After 1 month such mixtures produce about same amount of solids as brine alone. In contrast, 1:4 mixtures of Salton Sea water brine are still e x h i b i t i n g  large degrees of precipitation af ter  1 month and a t  least  three times as many solids (primarily sulfates plus brine mixtures. According t o  the chemical analyses i n  Table 5, s i l i ca  reaches quasi- equilibrium conditions ,after 4 hours for  Salton Sea brine mixtures and after 8 hours for  both River water-brine mixtures. Sulfate, however, has not reached equilibrium i n  either case and is still comin MAKEUP WATER PROCESSING REQUIREMENTS A ser ies  of bench-scale experiments were r u n  t o  determine the effectiveness of sludge contact on precipitation rates of particulates generated i n  1:4 mixtures of Salton Sea water and geother- mal brine. c\ j a r  testing apparatus was used for  these experiments: samples were mixed a t  a con- stant speed of 100 RPM a t  T 78-85% for  times varying fran 5 minutes t o  2 hours. Turbidity, sulfate and s i l i c a  measurements were made on the approximately two mlnutes set t l ing time. (see Table 6) show that  solutions approached quasi-equilibrium w i t h i n  the first 10 minutes. Turbidity also showed a rapid decrease during the f i r s t  5 minute interval as suspended particu- la tes  settled. On the basis of these experi- mental results,  we concluded that  reaction clarification is  a viable and efficient means of stabil izing mixtures of makeup water and brine. . i i s i l ica)  were formed i n  contrast t o  River water - 1.0 pm prefiltered supernatant af ter  allowing - Results from the first two experimental runs I E DRtT OF W E  CD1(IAtT On DISSOLVE0 SILICA AN0 SWATE OF SALrn SEA ITER-6EoMEm BRIE Irn) ms1q ma; ( f l I H )  1 2 Will RM 2 RUN 1 SIN 2 ----- --5s 326 m 1w 1482 .s 258 221 927 899 A 216 1% 891 ass M 1.1 - 203 - 9ol - 4s 1.0 - 197 - 881 - . n o -  1114 - 889 - 120 3 5  - - - - -  220 1% 891 865 , PILOT TEST RESULTS Incubation and injectabil i ty tes t s  were run  on effluents produced by the Magma Power Company 30 GPM throughput pi lot  reaction clar i f ier-  granular media preinjection processing system. These t e s t s  were performed t o  establish the iso- thermal (90%) chemical s tab i l i ty  and inject- ab i l i ty  of processed 1:4 mixtures of Salton Sea water and geothermal brine. results for  times up t o  24 processed effluents had achieved a quasi-equi- librium condition. Residual dissolved s i l i ca  and sulfate concentrations were consistent w i t h  results of the bench-scale experiments. Membrane f i l t r a t ion  t e s t s  (Figure 2) indicated that  processea effluents containing less than 2 ppm suspended solids are potentially Injectable. However, results of the tore t e s t  (Figure 2) indicated that  post-i n j ec t  ion bri ne-rock inter- actions can severely impair injection well injection makeup will significantly increase . 3 Raber e t  a l .  KAYENTA SANDSTONE CORE TEST: -*- 0.45 HICRON HEtiBRANE FILTER TEST: -0- (L/nIN) 8 2 4 6 8 10 12 14 ( 8  18 28 ClJMUlATIVE VOLUME CLITRES) FIGURE 2 The pH o f  the Salton Sea water-brine e f f l uen t  from the granular media f i l t e r  dropped from a nominal br ine pH value o f  5.7 t o  5.3. We bel ieve the pH change re f l ec ts  oxidation o f  f e r -  rous i r o n  i n  br ine  by the  admixture o f  oxygen- ated Salton Sea water. A f te r  the sea water- br ine mixture flowed through our sandstone core sample (nominal permeabil i ty t o  br ine o f  1100 Md), the  e f f luen t  pH rose t o  5.6. This e f fec t  on pH has been noted previously and i s  a t t r ibu ted  t o  dissolut ion o f  carbonate material i n  the core by the weakly acidic brine.4 Although addit ional experimental work w i l l  be required t o  more completely assess i n j e c t a b i l i t y  o f  makeup water-brine mixtures, our prel iminary resu l ts  indicate tha t  the f i n a l  e f f luen t  pH must not be lower than about 5.7 t o  avoid post-processing prec ip i ta t ion  induced by in te rac t ion  o f  in jected ef f luents and reservoir  matr ix materials. It can also be ant ic ipated tha t  premature mass breakthrough o f  in jected eff luents, d i lu ted  by Salton Sea makeup water additions, t o  production wells has the potent ia l  f o r  s ign i f i can t l y  worsening scal ing problems due t o  deposition o f  sulfates. Therefore, i n jec t i on  wel ls receiving makeup water additions should be located w i th  respect t o  minimizing potent ia l  mass breakthrough problems. ACKNOWLEDGEMENTS We thank J. L. Feathersone, Manager, Imperial Magma Company, f o r  h i s  help i n  obtaining br ine  samples from t h e i r  p i l o t  c l a r i f i e r - f i l t r a t i o n  system. C. H. Otto, R. Lim, W. P. Frey, and S. B. Deutscher provided f i e l d  analyt ical  support and F. E. Locke provided f i e l d  engineering support. Vetter Research, Laguna Beach, Cali fornia, provided chemical analyses of our makeup water samples. 1. 2. 3. 4. 5. REFERENCES Quong, R., Schoepflin, F., Stout, N. D., Tardi f f ,  6. E., and McLain, F. R., 1978, Processing o f  Geothermal b i n e  Ef f luen t  f o r  In ject ion:  Geothermal Resources Counci 1 , Transactions, Vol. 2, p. 551-554. Van Note, R. H., Featherstone. J. L., and Pawloski, B. S., 1978, A Cost-Effective Treatment System f o r  the  Stab i l i za t ion  o f  Spent Geothermal Brines: Presented a t  2nd Internat ional  LBL Well .Testing Symposium @ct. 25-27) Berkeley, CA. Netherton, R. and Owen, L. B., 1978, Apparatus f o r  the  F i e l d  Evaluation o f  Geothrmal E f f luen t  In ject ion:  Geothermal Resources Council, Transactions, Vol. 2, p. Tewhey, J. D., Chan, M. A., Kasameyer, P. W., and Owen, L. B., 1978, Development o f  I n jec t i on  C r i t e r i a  f o r  Geothermal Resources: Geothermal Resources Council, Transactions, Wolery, T. J, 1979, Computer Simulation o f  Temperature-Dependent Equil  i brium Precipitat ion: Geothermal Resources Council, Transactions, t h i s  volume. 487-490. Vol. 2, p. 649-652. "Work performed under the auspices o f  the U. S. Department o f  Energy by the Lawrence L i venore  Laboratory under contract number W-7405-ENG-48. 'I NOTICE This report was prepared as an account of work sponsored by the United States Government. Neither the United States nor the United States Department of Energy, nor any of their employees, nor any of their contractors, subcontractors, or their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility fot the accuracy, completeness or usefulness of any information, apparatus, product or process disclosed, or represents that its use would not infringe privately-owned rights. Reference to a company or product name does not imply approval or recommendation of the product by the University of California or the U.S. Department of Energy to the exclusion of others that may be suitable. ~ 4 * W 4 c i 

Using surface waters for supplementing injection at the Salton Sea Geothermal Field (SSGF), Southern California

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Using surface waters for supplementing injection at the Salton Sea Geothermal Field (SSGF), Southern California

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