Characterization and Origin of Brines from the Bakken-Three Forks Petroleum System in the Williston Basin, USA

2017 ◽  
Vol 54 (3) ◽  
pp. 203-221 ◽  
Author(s):  
Zell Peterman ◽  
Joanna Thamke ◽  
Kiyoto Futa ◽  
Thomas Oliver

Brine (also referred to as ‘produced water’) samples were collected from 28 wells producing oil from the Late Devonian-Early Mississippian Bakken and Three Forks Formations in the Williston Basin of eastern Montana and western North Dakota. The samples were analyzed for major ions, trace metals, stable isotopes, and strontium isotopes. The brines in these formations are highly saline with total dissolved solids averaging 308 g/L, almost ten times the salinity of modern seawater. Relative to modern seawater, the brines are enriched approximately 10 to 20 times in [Na], [K], [Cl], and [Br]. Greater enrichments of 100 to 400 times in [Li], [B], [Sr] and [Rb], and 2,000 to 10,000 times in [Cs] and [Ba] are probably due to water-rock interaction (WRI). WRI is further indicated by 87Sr/86Sr values typically between 0.710 and 0.711—considerably larger than marine values of 0.7081 to 0.7083 during this depositional interval. Bakken Formation sediments were deposited in a stratified water column with salinity increasing with depth. The deeper water may have been saturated in calcium carbonate and possibly gypsum, but there is no evidence that halite saturation had been attained. Therefore, brines may have been introduced into the Bakken Formation from the underlying Devonian Prairie Formation or from the overlying Charles Formation before these brines were diluted or replaced by meteoric water. Alternatively, salinity of the native pore water was increased by membrane filtration driven by overpressuring within the Bakken Formation.

2013 ◽  
Vol 17 (7) ◽  
pp. 2917-2928 ◽  
Author(s):  
G. Mongelli ◽  
S. Monni ◽  
G. Oggiano ◽  
M. Paternoster ◽  
R. Sinisi

Abstract. Throughout the Mediterranean, salinization threatens water quality, especially in coastal areas. This salinization is the result of concomitant processes related to both seawater intrusion and water–rock interaction, which in some cases are virtually indistinguishable. In the Nurra region of northwestern Sardinia, recent salinization related to marine water intrusion has been caused by aquifer exploitation. However, the geology of this region records a long history from the Palaeozoic to the Quaternary, and is structurally complex and comprises a wide variety of lithologies, including Triassic evaporites. Determining the origin of the saline component of the Jurassic and Triassic aquifers in the Nurra region may provide a useful and more general model for salinization processes in the Mediterranean area, where the occurrence of evaporitic rocks in coastal aquifers is a common feature. In addition, due to intensive human activity and recent climatic change, the Nurra has become vulnerable to desertification and, in common with other Mediterranean islands, surface water resources periodically suffer from severe shortages. With this in mind, we report new data regarding brackish and surface waters (outcrop and lake samples) of the Na-Cl type from the Nurra region, including major ions and selected trace elements (B, Br, I, and Sr), in addition to isotopic data including δ18O, δD in water, and δ34S and δ18O in dissolved SO4. To identify the origin of the salinity more precisely, we also analysed the mineralogical and isotopic composition of Triassic evaporites. The brackish waters have Cl contents of up to 2025 mg L−1 , and the ratios between dissolved ions and Cl, with the exception of the Br / Cl ratio, are not those expected on the basis of simple mixing between rainwater and seawater. The δ18O and δD data indicate that most of the waters fall between the regional meteoric water line and the global meteoric water line, supporting the conclusion that they are meteoric in origin. A significant consequence of the meteoric origin of the Na-Cl-type water studied here is that the Br / Cl ratio, extensively used to assess the origin of salinity in fresh water, should be used with care in carbonate aquifers that are near the coast. Overall, δ34S and δ18O levels in dissolved SO4 suggest that water–rock interaction is responsible for the Na-Cl brackish composition of the water hosted by the Jurassic and Triassic aquifers of the Nurra, and this is consistent with the geology and lithological features of the study area. Evaporite dissolution may also explain the high Cl content, as halite was detected within the gypsum deposits. Finally, these Na-Cl brackish waters are undersaturated with respect to the more soluble salts, implying that in a climate evolving toward semi-arid conditions, the salinization process could intensify dramatically in the near future.


2015 ◽  
Author(s):  
Darren D. Schmidt ◽  
P.E.. E. Statoil ◽  
Bruce MacKay ◽  
Brandon Williams ◽  
Frederick Beck ◽  
...  

Abstract The use of produced water in well stimulation is not straightforward and presents numerous challenges. A case study using 100% produced water from the Bakken Formation to stimulate a two-well pad in Williams County North Dakota is presented. The well stimulations include a typical 30-stage plug & perf completion using a hybrid fluid design consisting of slickwater and crosslinked gel. The pad includes both a Middle Bakken horizontal and a Three Forks horizontal well. This case study addresses the challenges and obstacles faced over a two-year period since embarking on the first field experiment using 50% produced water to stimulate a well in the same area. A number of first-time experiences have been addressed in the areas of cost, fluid chemistry, water quality, facilities, logistics, storage, and regulatory. All of these factors appeared to be insurmountable barriers in the early phases of considering the use of produced water for well stimulation. However over time and with careful developments along the way, we have progressed to the point of practicality for such endeavors. This case study presents the barriers, technical issues, technology development, current practice, and expected progress of produced water stimulation in the Williston Basin.


Author(s):  
Carleton R. Bern ◽  
Justin E. Birdwell ◽  
Aaron M. Jubb

Comparisons of hydrocarbon-produced waters from multiple basins and experiments using multiple shales illustrate water–rock interaction influence on produced water chemistry.


Clay Minerals ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 591-608 ◽  
Author(s):  
M. Osborne ◽  
R. S. Haszeldine ◽  
A. E. Fallick

AbstractDiagenetic kaolinite in reservoir sandstones of the Brent Group precipitated following the dissolution of detrial feldspar. Two distinct morphologies of kaolinite occur: (1) early diagenetic vermiform kaolinite which is often associated with expanded detrital micas; (2) later diagenetic ‘blocky’ kaolinite. Combined hydrogen and oxygen isotopic studies suggest that vermiform kaolinite precipitated at 25–50°C, and blocky kaolinite at 50–80°C, from pore-waters of a similar isotopic composition (δ18O = −6.5 to −3.5‰). These pore-waters are interpreted to be either a mixture of meteoric and compactional waters, or alternatively a meteoric water that had evolved isotopically due to water-rock interaction. Kaolinite precipitation occurred predominantly during the late Cretaceous to early Eocene. Influx of meteoric water into the Brent Group, probably occurred during the Palaeocene. Fluid flow across the entire basin was driven by a hydrostatic head on the East Shetland Platform palaeo-landmass to the west. The development of the two kaolinite morphologies is possibly related to the degree of supersaturation at the time of precipitation. At low degrees of supersaturation, vermiform kaolinite precipitated slowly upon detrital mica surfaces. Blocky kaolinite precipitated more rapidly into open pore-space at higher degrees of supersaturation. Precipitation of blocky kaolinite was perhaps triggered by the decay of oxalate.


2018 ◽  
Vol 69 (8) ◽  
pp. 1290 ◽  
Author(s):  
Mohammed Bahir ◽  
Salah Ouhamdouch ◽  
Paulà M. Carreira

Study of the Cenomanian–Turonian and Plio–Quaternary aquifers of Essaouira basin (Western Morocco), based on the interpretation of geochemical (major elements) and isotopic (18O, 2H, 13C and 14C) data, has aided the understanding of the hydrodynamics of these aquifers, which is greatly affected by tectonics. Hydrochemical characteristics based on the bivariate diagrams of major ions (Cl–, SO42–, NO3–, HCO3–, Na+, Mg2+, K+ and Ca2+) and electrical conductivity and mineral saturation indices indicate that the origins of groundwater mineralisation are the result of: (1) evaporite dissolution; (2) cation exchange reactions; (3) and evaporation processes. Radiogenic isotopes (3H and 14C) have highlighted the presence of significant recent recharge in the eastern part of the basin, with groundwater moving according to the general flow path (south-east to north-west). Stable isotope data from the Essaouira basin plot along the Global Meteoric Water Line and below the Local Meteoric Water Line. This suggests that groundwater has been recharged under several different climate regimes.


Heliyon ◽  
2020 ◽  
Vol 6 (3) ◽  
pp. e03590
Author(s):  
Matthew S. Varonka ◽  
Tanya J. Gallegos ◽  
Anne L. Bates ◽  
Colin Doolan ◽  
William H. Orem

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 358
Author(s):  
Randy L. Stotler ◽  
Matthew F. Kirk ◽  
K. David Newell ◽  
Robert H. Goldstein ◽  
Shaun K. Frape ◽  
...  

This study characterizes the δ37Cl, δ81Br, and 87Sr/86Sr of coal bed methane produced fluids from Pennsylvanian Cherokee Group coals of the Cherokee Basin in southeast Kansas, USA. The δ37Cl, δ81Br, and 87Sr/86Sr values range between −0.81 and +0.68‰ (SMOC), −0.63 and +3.17‰ (SMOB), and 0.70880 and 0.71109, respectively. A large percentage of samples have δ81Br above +2.00‰. Two fluid groups were identified on the basis of K/Br, Br/Cl, and Ca/Mg ratios, temperature, He content, δ2H, δ18O, δ81Br, and 87Sr/86Sr. Both fluid groups have geochemical similarities to fluids in Cambrian, Ordovician, and Mississippian units. Lower salinity and higher temperature fluids from deeper units are leaking up into the Cherokee Group and mixing with a higher salinity fluid with higher δ81Br and more radiogenic 87Sr/86Sr. Variation in δ37Cl indicates an unknown process other than mixing is affecting the salinity. This process does not appear to be related to evaporation, evaporite dissolution, or diffusion. Insufficient data are available to evaluate halide–gas or water–rock interaction, but halide–gas interactions are not likely a significant contributor to high δ81Br. Rather, interactions with organically bound bromine and soluble chloride within the coal could have the strongest effect on δ37Cl and δ81Br values.


Author(s):  
Nnenesi A. Kgabi ◽  
Eliot Atekwana ◽  
Johanna Ithindi ◽  
Martha Uugwanga ◽  
Kay Knoeller ◽  
...  

Abstract. We assessed environmental tracers in groundwater in two contrasting basins in Namibia; the Kuiseb Basin, which is a predominantly dry area and the Cuvelai-Etosha Basin, which is prone to alternating floods and droughts. We aimed to determine why the quality of groundwater was different in these two basins which occur in an arid environment. We analysed groundwater and surface water for the stable isotope ratios of hydrogen (δ2H) and oxygen (δ18O) by cavity ring-down spectroscopy and metals by inductively coupled plasma mass spectrometry. The δ2H and δ18O of surface water in the Cuvelai-Etosha Basin plot on an evaporation trend below the global meteoric water line (GMWL) and the local meteoric water line (LMWL). The δ2H and δ18O of some groundwater samples in the Cuvelai-Etosha Basin also plot on the evaporation trend, indicating recharge by evaporated rain or evaporated surface water. In contrast, the δ2H and δ18O of groundwater samples in the Kuiseb Basin plot mostly along the GMWL and the LMWL, indicating direct recharge from unevaporated rain or unevaporated surface water. Fifty percent of groundwater samples in the Cuvelai-Etosha Basin was potable (salinity < 1 ppt) compared to 79 % in the Kuiseb Basin. The high salinity in the groundwater of the Cuvelai-Etosha Basin does not appear to be caused by evaporation of water (evapo-concentration) on surface prior to groundwater recharge, but rather by the weathering of the Kalahari sediments. The low salinity in the Kuiseb Basin derives from rapid recharge of groundwater by unevaporated rain and limited weathering of the crystalline rocks. The order of abundance of cations in the Kuiseb Basin is Na > K > Ca > Mg vs. Na > Mg > Ca > K for the Cuvelai-Etosha Basin. For metals in the Kuiseb Basin the order of abundance is Fe > Al > V > As > Zn vs. Al > Fe > V> As > Zn for the Cuvelai-Etosha Basin. The relative abundance of cations and metals are attributed to the differences in geology of the basins and the extent of water-rock interaction. Our results show that the quality of groundwater in Cuvelai-Etosha Basin and Kuiseb Basin which vary in the extent of aridity, is controlled by the extent of water-rock interaction at the surface and in the groundwater aquifer.


2020 ◽  
Vol 12 (1) ◽  
pp. 1146-1157
Author(s):  
Mingyang Du ◽  
Caifang Wu ◽  
He Zhou ◽  
Shasha Zhang ◽  
Erchao Zhang

AbstractThe water produced from the coalbed methane (CBM) wells contains abundant geochemical information, which is of great significance in evaluating the productivity of these wells. Based on the data of water produced from five CBM wells, geochemical characteristics of the produced water and its influence on the productivity of the wells are analyzed in Laochang Block. The results show that with the increase in the produced water of the five wells, δD and δ18O show a downward trend in general, reflecting that the influence of coal seams and surrounding rock on the produced water is weak, while the water–rock interaction of the Y-3 and Y-5 wells is more stable than that of the Y-1, Y-2, and Y-4 wells. Combining the water production characteristics of the Y-3 and Y-5 wells with better drainage and recovery effects, it is proposed that 0 ≤ σM < 0.3 and 0 ≤ σY < 600 or 0.7 < σM < 0.8 and 1,200 < σY < 1,300, and the fluctuation ranges of Ca2+, Mg2+, HCO3− and SO42− can provide a basis for quantitative characterization and evaluation of CBM well production.


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