- 112 -

Underground Storage Potential of the Bedded Salt Deposits of Saskatchewan: Project Outline and Rationale by Frank Simpson1 and Garrett M. Connolly1

Solution-mined caverns in bedded halite Evaporite were presented by Kent (1968) and deposits of the Middle revonian Prairie fblter (1969). Simpson and r:ennison (1975) Evaporite have been utilized by industrial discussed the significance of solution­ operators in Saskatchewan for the underground generated collapse features as sources of storage of hydrocarbons sirx::e 1962. Both dry potential hazard in relation to the subsurface natural gas (~) and liquefied petroleun disposal of fluid industrial wastes. Simpson gases (IPG) are currently stored in these salt (1978) evaluated the main causes postulated caverns. At one location, waste mercury for localized salt solutioning in the light of compounds are contained and confined in salt extra-basin tectonic controls, notably the caverns which were washed to supply brine for interaction of plates along the western margin a chlor-alkali plant. In addition, there is of tbrth llmerica. potential for underground storage in caverns, resulting from the solution~ining of halite D.lring the sunmer of 1982, a study to evaluate and potash respectively at two separate sites the underground storage potential of the in the province, and in excavated subsurface bedded salt deposits of Saskatchewan was space, originating from conventional initiated with the support of Saskatchewan room-and-pillar mining of potash-bearing Ehergy and Mines as a Master's thesis project strata at ten other locations. by the junior author. An assessment of the possible environmental impact of existing salt Evaporites are interbedded with carbonates and caverns was undertaken. Fbur areas (~lville, generally subordinate argillaceous rocks Iegina, Saskatoon anCretaceous in age, were analyzed to the Ufper r:evonian J:avidson Evaporite member investigate the trends of solution-generated of the Souris River Fbrmation incorporate collapse features next to the salt caverns. halite deposits with the potential for In addition, a questionnaire was designed and conmercial developrent of storage caverns over distributed to companies engaged in a wide area. fblter (1969) described urilerground storage operations in lithologic variation in the Prairie Evaporite Saskatchewan. '!his questionnaire comprises 38 of southern Saskatchewan, and a recent account questions concerning the design ari1 operation by W'.)rsley aril F\.lzesy (1979) presented new of a sa1t cavern storage facilities and it was data on the formation in the southeastern part used to surrrna.rize the experience of industrial of the province. 'Ihe stratigrap~ of the operators in a standardized way. tavidson Evaporite in southern Saskatchewan was discussed by lane (1964), and a paper by Kendall (1976) dealt with occurrences of the Cl.lrrent Status of Salt-cavern Storage unit to the west and east of Saskatoon. ~nty-six salt caverns in eight storage A major potential hazard to the safe operation facilities listed in Table l are used for of storage facilities in the bedded salt hydrocarbon storage in Saskatchewan. deposits of southern Saskatchewan is presented Solution-caverns for purposes other than by naturally formed structures caused by the hydrocarbon storage are listed in Table 2. collapse of superincumbent strata at the sites 'Illese include solution~ining projects for of localized solution of halite and other potash exploitation~ Kalium d'l.emicals Ltd. soluble minerals. 'Ihe fracture-bounded sinks in 'lwp 17 R]e 2SW2, for halite production by COITIIl)nly associated with these features Iexter Olemicals Ltd. in Twp 40, R]e 22W3, and provide possible conduits for the vertical for industrial waste-disposal by the Saskatoon movement of fluids stored in nearby artificial 01emical Division of the Prince Albert Pulp caverns. 1¥::Counts of the distribution and O:imp:i.ny Ltd. in 'lwp 37 R]e SW3. ~rcury time of formation of multistage salt-solution compounds derived from the operation of a features associated with the Prairie chlor-alkali plant are disposed of at the last facility (Sill'lpSon and r:ennison 1975) • In addition the locations of experimental l r:ep:i.rtment of Ceology, Uliversity of solution~ining test wells are shown in Windsor~ Windsor, Ontario. 'Iable 2. - ll3 -

Macdonald and Broughton, 1980 Fuzesy, 1982

I ./ I ,/ · 1 ,, 'V"----('- i ,,--- _..---1 / I r· r...... ' · I I , . ,:.. 'i

. i I . l

'· I ! [.

1',I 1"(1

,,- \ I

Figure 1 -Sketch map showing location of areas of detailed study in southern Saskatchewan 1, study area: 2, southern perimeter of Precambrian Shield: 3, edge of Prairie Evaporite (Middle Devonian) salt - 114 -

'Iable 1. Salt-cavern Storage Facilities in Saskatchewan (After Simpson and r:ennison, 1975)

ltlmber Year Average 'lbtal Storage Pef. Salt-cavern Product of First Cavern Capacity N::>. Storage Facility Stored Caverns Storage [epth (m) (x 106 m3)

1 D:Jme ~lville LPG 5 1962 1057.7 0.62 (sec. 29-22-6W2)

2 SPC Brewer natural gas 1 1963 1027.2 10.05 (sec. 15-23-6W2)

3 Pacific Erlenwold LPG 2 1966 1542.3 0.16 (sec. 22-16-18W2)

4 SPC Iegina natural gas 4 1964 1639.2 96.9 (sec. 27-16-2CM'2)

5 Procor ~ina LPG 8 1972 1687.1 0.69 (sec. 29-l 7-2CW2)

6 SPC Prud 'horrme natural gas 2 1965 1008.9 33.4 (sec. 12-38-28W2)

7 SPC Landis natural gas 2 1976 1233.2 59.47 (sec. 36-37-18W3)

8 D:Jme Ker robert LPG 2 1971 1328.9 0.12 (sec. 34-33-22W3)

locations of the salt-cavern storage escape. 'Ihe main stages of decision analysis facilities listed in 'Iable 1 and the main in a study of legislation against air caverns from 'Iable 2, mentioned above, are pollution (Ellis and Keeney 1972) were shown in Figure 2, together with the sites at followed by Simpson and r:ennison (1975) in which conventional room-and-pillar mining of their study of waste injection systems. potash in the Prairie Evaporite is carried out. 'Ihese stages are presented as a model for the system-design process in Figure 4. 'Ihe 'lbwards a Systematic Approach to the Siting of questionnaire-related part of the present Salt Caverns study will facilitate optimization of

Che of the major advantage s of underground UNCO NT ROL LEO U NMfASUREO storage of fluids in salt caverns lies in the IN~'U TS OiJ TPU T!.> fact that the injection-related movement of I ' / MOBILE energy and materials (Fig . 3) is restricted to Y: SYSH..M /E NV IF.O NM( NT EN V IRONME NT INTE RFACE. a known volume of solution-mined subsurface ' space. 'lhis movement can be carefully \ ! NJE~:l~:U-R~:~~: TfD ACTUATO~ S P A( [ TR A. f'.. SO U( ( R controlled with the aid of a suitable i. e. lNJEC T JO r-. SYS r EM i.e MONITO RIN G pressure-monitoring device. 'Ihis is in WEll nn l!C E contrast to injection systems, in which the - ·- { ~';~ ~:~~~ M!::ASUREO storage space is provided by naturally CO NTROLL ED occurring or artificially enhanced porosity, tNFUT S ·: urrurs where the volume of injection-affected subsurface space is not fixed with precision and is frequently affected by regional and local characteristics of the hydrogeologic regime (Simpson and I:ennison, 1975). As noted above, salt-cavern storage facilites in close proximity to naturally occurring Figure 3- The flow of energy and materials across the interface solution-generated collapse features present between the in1ection-affected subsurface space system and its the possibility of hazard, arising from fluid environment - 115 -

!ahl ~ ;., _ Cor.tro l le(l So lution oi1~1,..,o va l L)f Pr uiT'ie lv,iporite ~ [ >;o;I.J'S. i v1? o f ~t o r· ayl' C,Wl' f n LJ(•V1~ h 1pnH'rtt in Sa.s ka t<:11("N:in ( Aft er '.) i 111 psun ) ------·- ···-- .. Co:1,p l 1: t ion .So luLim1 So luti o n :.c ll(s) llat e/ on !nt0rvo 1 Cu rre 11t Fresn-·.~·dter Hr i r1~ - lJ ·i SpU '>

------~------· 4 .

I. Ce rw r

2. 1-w "l"j(Je n /\)t a. sll l I v6 3. 0 su5p cndei.:1 ~·1,:rn nv ill,~ '-.tJrf il.C:1' 'iOl u t. i on-11 11 ri l nq l3 elhune ( -1 7- i.' U-i'J t e st: we l I ( Sh' ?- Ji' - 2t:- 2 3Vl' 2 J

LurnSUfr1 Put~\~(1 :: susp endeo Htmnville so l:..i t i on-min inq Bet. nunr~ 2-1 7-i:U-/ J '.<"; t we l 1 (S f ?-I i-! c - 23• 2)

4. I ui:is.d,?n r,Ha.sll 4 Aug . 1% / susrwnJed surf Jee :;,Jiution -ini ni nq Het hurn~ 2-1 / - l U-?J t <:>s t we: l 1 {NC t'-i 7-2U- 2Ji,,' /}

ly11 tJ

6. SWP tivu IJ1!r LJ.Ke J ul, J 9tJ .;. i Obti . b su s penrled surf ace Mn nnv i l l (> •' Xpt:ri.'!1l" nta I JOtas !i ­ 16-1 1;-30-23 br itH' l{'Sl 1-,·~ ll (Ctr . 16-ld-.lG-,3•'2)

7. Sh'P 3 Bou J<1e r I akc 1066 . 0 1·1:ann v i ll P so l :: I. ,,_H1-rn 1n i ng 16-1 1' - Jll -d t '::'s t ·,·II? i I (Ctr. 16-l ~- c0-23h12 ) rs . )tony ~L) J ch rv . 2 I IU6. Y Mann v i l le Mann vi 1·1 e potash so lut ·i on­ ( SW lr-11 - 17-/4•/.) ·1:1 n i n9 t~~ s l .-.·t~l1

1(1. KJ l i rm 0 1em ) tm1y lie <.1c h Mtly l % l oper ,it i ng surface Sour i s. \·a l Je _:y tt1c 0111 y U>irlne r c ; 11 1 ('.,ecs. 24, Zb & 26 -l / -24W 2) µ0 L<1s h si>l1Jli!~n-:r· inf! ;:,p~r,1t ion in l he world

11. f ind l at e r l'o t asl, I 074 . O al.J

12 . Fi ntJl <.1le r PutJstl Soµt. 1962 I S24. 0 aba ncJo nN1 Mann 11 i J "le 8 i rdbea r potash 11iltl t well 16A- 10-ci-/" ( Ct r- S\; 16-IU-2 1-2SW 2 )

1 J . Norlt1~rn Roc h!J dl e I ~fi 7 WZ4. 0 operat i nq su rface br in i ng we ll 3- , 6- 31- ; WJ 1094. 2 ( Sec. J -26 - 37 - , ,1 3 ) l 4. Nurtt1e rn :~ocho a I e .;111. 1%2 l039. 4 s ud ace !Jri n 1nq wr .11 4- 26- J/ - o 1035. 9 ( ctr. 4-26 - 3 7-;w.!)

I S. Nortt1e r-n 1~oc t1a J le 1%/ 104. 7 oper J. t i nq bri n i rH1 we l1 ~- 26- ~,1-:i ( o€C. ;,-?h-Ji -o'• .l)

I u. 1;,r, 4-2-31- 6 dlln. 1962 97~. 4 abanrlone(1 surt Jc.:e Mann v i1 re pot. ;:,. ~ r1 sL• l•Jt i ori­ (Ct r , 4- 2- J i -~W J) rn i ne t est. we ll

1 I . D'.>P 4-211- 3/-6 W3 ,iu11. 1 Y6Z 97, . 4 M;rn nvi l lc- ::io td~h ~,:1lutim 1- (Ctr. 4-2--< i - 6W3) !T1 i 11 (.' t !:'(, t. WI: 11

It. Frct iri e \a lt Co 111µJ11y No J 1%1 ? l U91 . 3 ope r e ii ng sur f J.C 1~ (,ec . 14-4-4(J-U a 3)

19. fJr a iri c '.:>J lt ( omvany No . ]()'i i . j s ur f ace :,u µe r o w l b~·ininq wf"! ll ( Sec . l 4-4- 40 - 22W3)

LG . Pr(i i r l e Sd l t Company r·.o . rcb. H41 11197 . 3 ~; uspernl ed SU T'f dCP i)ri n ing w1~l l ( NE l o- 4-40- ,?• 3)

? l. Pru iri e Su1L Co111~1rJ ny I\O . J,.i n , 194/ I U97 . 3 p I J, ~, qen IJ,..1. ck surf a cf! ~ur face br inir1q l'.'f~ll ( r,E I o- 4 -40- 23i3) l o SWD

;,; . Verbat a t,:i . I aban

1priur t o 19 /J l! l <:. µu s.J l wJs; l o a surf<1Cf" l agoon ;rnd l akr~. - 116 -

11: 1 - -··1 e i credit: Fuzesy, 1982 Simpson and Dennison. 1975 I I I I I I I I I I I I ,1 ~ ;,-1 I :; 1 I , I I f I I ' ' I I I I I I I I I ... i) I

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• Q 0 I I I I I '" I I I ~ I ~ I I {· ....,1 I ""''·"' ' 1 I I I l -,n I ' 'I \ I I I I

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I' / '-"\.r " / '~ 'V >< ,. . _,-,., ' ·-~"' '\a ' ' '"' <)+~ ~ ~ Figure 2-Cavern storage and mining operations in relation to solution-generated collapse features associated with the Prairie Evaporite (Middle Devonian). 1, edge of Prairie Evaporite salt ; 2, edge of Prairie Evaporite anhydrite; 3, local salt solution (seismic anomaly); 4, northern limit of Colorado (Cretaceous); 5, southern perimeter of Precambrian Shield; 6, linear solution features; 7, sinks and large-scale circular structures; 8, trend of known multistage salt-solution structures; 9, ma1or seismic positive elements; 10, aquifer natural-gas storage; 11. LPG storage cavern, natural gas storage cavern. chemical plant facility; 12, shaft mining; 13, solution mining. - 117 -

1 j '"'rf',, o- ~ ,, I l

STAU I. TURIN GH S'f">l; HE S!S AN ALYSIS I H ATI ON AL t OF '-'~ + .__....1 F""I ALlE RNA"T IVE I L \IALUATI ON 1""""'" =r·,! '.'C~' -

~ CO NCEPT ' _L --- OPT IMl7A"'"'IO N ~ FOR MULATION z e----- ·- -· - -- - -1----- <>: SYSTEM _J DEFINITION Figure 4- Model for system-design process. LJ.J j.E=_ ....J WATER U SOURCE >- u z WELL (collllTU1s in Figure 5) with a view to Q SIT E w ~I------+--+--+----+--+----+--+----, sumnarizing the engineering parameters found LL in TARGET have :J 3 HOR IZON to been nost favourable in a given ·- ~-~+--+----+--+----, geological setting. I 8 BRINING ~t<>:,_____ W_E_LL ____ -+- t- MONITORING Strata younger than the Devonian salt-bearing (1) 1 DEVICE r 1--+------>---+- ·-~ -1---- sequences are frequently seen to reflect (l)I OPERATION AND controls of sedimentation by multistage salt 1~1---M_AI_N_TE_N_A_N_CE_--+--+--+----+-~ll---+-+--I--~ solution and, in particular, by that I ::, ABANDONMENT + _l associated with the Prairie Evaporite. 'lhis I CO NTINUED MONITOR I_~~ ---···· _ . ~ - · ···- __ .. •..••_ .I...... ___ type of causal relationship lends itself to Figure 5-Life cycle/design process matrix for th e salt-cavern the extrapolation of solution-generated storage decision system. collapse features along trerds, defined by younger depositional systems, allowing the References safe siting of salt-cavern storage facilities at locations which are distant from such Oiristopher, J.E. (1980): 'lhe Lower trerds. A relationship with considerable Cretaceous Mannville Group of Saskatchewan promise in this regard is provided by spatial - a tectonic overview; in Lloydrninster and coin:::idence between local salt-solution Beyond: G20logy of Mannville HYdrocarbon features, associated with the Prairie 1€servoirs, eds. L.S. Beck, J.E. Evaporite (Fuzesy, 1982) and the axes of Dina Glristopher and D.M. Kent; Sask. G20l. valley-fill deposits (Mannville Group, Lower Soc., Spec. Publ. no. 5, p. 3-32. Cretaceous) (Glristopher, 1980), 'lhe importan:::e of this relationship, shown in Glristopher, J.E., Kent, D.M. and Figure 6, is underscored by the colllIDn Simpson, F. (1971): ~drocarbon potential practice of waste-brine disposal urder high of Saskatchewan; Sask. J:ep. Min. Resour., pressure into Mannville reservoirs, reported Rep. 157, 47 p. by Simpson and Dennison (1975). Ellis, H.M. and Keeney, R. L. (1972}: A national approach for government decisions Jlcknowledgments concerning air pollution; in Analysis of Public Systems, eds. A.W. Drake, R.L. 'lhe cost of this study was in part defrayed by Keeney and P .M. r.t)rse; M. I. T. Press, Q:Jerating Grant A9174 from the National Massachusetts, p. 376-400. Sciences and Engineering !€search Q:>un:::il of Canada. Support from Saskatchewan Energy and Fuzesy, A. (1982}: R>tash in Saskatchewan; Mines is also gratefully acknowledged. Sask. Energy and Mines, Rep. 181, 44 p. 'lhe authors acknowledge their indebtedness to Iblter, M.E. (1969}: 'lhe Middle i:evonian the following individuals, who supplied Prairie Evaporite of Saskatchewan; Sask. information on the storage of hydrocarbons in J:ep. Miner. Resour., Rep. 123, 134 p. salt caverns by their companies: E. Scott (D:>rne Fetroleurn Limited), D. NYgaard Kendall, A.C. (1976): Bedded halites in the (Fetro-canada Limited), G. Dlouhy and R. SOuris River Formation (Levonian): potash Fleury (Procor Limited) and N.G. Crossley mining district around Saskatoon; in (Saskatchewan R>wer Cbrporation). Surrroary of Investigations 1976, Sask. G201. Surv., p. 84-86. - 118 -

Christopher. 1980 Fuzesy, 1982

':, ::· ?~X) K. • :'J1•1c tr c::, ~ - "'.'" _ _L____ c__::__:_===:::o

Figure 6-Solution-generated collapse features associated with the Prairie Evaporite (Middle Devonian) and axes of Dina (Lower Cretaceous) valley fill. 1, edge o! Prairie Evaporite anhydrite; 2, edge of Prairie Evaporite salt; 3, axis of D,na valley fill; 4. structural linears. 5. local salt solution (seismic anomaly). - 119 -

Kent, D.M. (1968): 'Ihe geology of the Q?per Simpson, F. (1978): Plate-tectonic scenario tevonian Saskatchewan Group and equivalent for solution-controlled collapse rocks in western Saskatchewan and adjacent structures in Paleozoic carbonate­ areas; Sask. tep. Miner. Resour., l:Ep. 99, evaporite sequeoce of the northern 224 p. Williston basin region; in 'Ihe EJ:::onomic Geology of the Williston Basin, M:mt, (1974): 'Ihe relationship between Geol. Soc., p. 147-150. hydrocarbon accLDnulations and basement structural elements in the northern Simpson, F. and tennison, E.G. (1975): Williston basin; in Euels: a Geological Subsurface waste-

L:me, O.M, (1964): Souris River Formation W'.:>rsley, N. and F\lzesy, A. (1979) : 'Ihe in southern Saskatchewan; Sask. tep. potash-bearing members of the ~vonian Miner. Resour., Rep. 92, 72 p. Prairie Evaporite of southeastern Saskatchewan, south of the mining area; EJ:x>n. Geol., v. 74, p. 377-388.