Geochemical characteristics of produced water from coalbed methane wells and its influence on productivity in Laochang Coalfield, China

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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Geochemical Characteristics and Productivity Response of Produced Water from Coalbed Methane Wells in the Yuwang Block, Eastern Yunnan, China

Geofluids ◽

10.1155/2020/5702031 ◽

2020 ◽

Vol 2020 ◽

pp. 1-11

Author(s):

Mingyang Du ◽

Xiaojuan Yao ◽

Shasha Zhang ◽

He Zhou ◽

Caifang Wu ◽

...

Keyword(s):

Water Samples ◽

Coalbed Methane ◽

Produced Water ◽

Dissolved Inorganic Carbon ◽

Geochemical Characteristics ◽

Water Type ◽

Coal Seams ◽

Rock Interaction ◽

Cbm Production ◽

Using Data

Coalbed methane (CBM) well-produced water contains abundant geochemical information that can guide productivity predictions of CBM wells. The geochemical characteristics and productivity responses of water produced from six CBM wells in the Yuwang block, eastern Yunnan, were analyzed using data of conventional ions, hydrogen and oxygen isotopes, and dissolved inorganic carbon (DIC). The results showed that the produced water type of well L-3 is mainly Na-HCO3, while those from the other five wells are Na-Cl-HCO3. The isotope characteristics of produced water are affected greatly by water-rock interaction. Combined with the enrichment mechanisms of isotopes D and 18O, we found that the water samples exhibit an obvious D drift trend relative to the local meteoric water line. The 13C enrichment of DIC in the water samples suggests that DIC is mainly produced by the dissolution of carbonate minerals in coal seams. The concentration of HCO3-, D drift trend, and enrichment of 13CDIC in produced water are positively correlated with CBM production, which can be verified by wells L-4 and L-6.

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Water–rock interaction and the concentrations of major, trace, and rare earth elements in hydrocarbon-associated produced waters of the United States

Environmental Science Processes & Impacts ◽

10.1039/d1em00080b ◽

2021 ◽

Author(s):

Carleton R. Bern ◽

Justin E. Birdwell ◽

Aaron M. Jubb

Keyword(s):

United States ◽

Rare Earth ◽

Rare Earth Elements ◽

Water Chemistry ◽

Produced Water ◽

The United States ◽

Rock Interaction ◽

Produced Waters ◽

Water Rock Interaction

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

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Stable Bromine Isotopic Composition of Coal Bed Methane (CBM) Produced Water, the Occurrence of Enriched 81Br, and Implications for Fluid Flow in the Midcontinent, USA

Minerals ◽

10.3390/min11040358 ◽

2021 ◽

Vol 11 (4) ◽

pp. 358

Author(s):

Randy L. Stotler ◽

Matthew F. Kirk ◽

K. David Newell ◽

Robert H. Goldstein ◽

Shaun K. Frape ◽

...

Keyword(s):

Produced Water ◽

Coal Bed ◽

Coal Bed Methane ◽

Rock Interaction ◽

Higher Temperature ◽

Cherokee Group ◽

Gas Interactions ◽

Two Fluid ◽

Midcontinent Usa ◽

Water Rock Interaction

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.

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The pilot appraisal of acid fracturing of coalbed methane reservoir in southeast Qinshui Basin, China

Earth Sciences Research Journal ◽

10.15446/esrj.v20n4.61633 ◽

2016 ◽

Vol 20 (4) ◽

pp. 1 ◽

Cited By ~ 3

Author(s):

Yu Yang ◽

Chengwei Zhang ◽

Huijun Tian ◽

Wangang Chen ◽

Xiadong Peng ◽

...

Keyword(s):

Hydraulic Fracturing ◽

Coalbed Methane ◽

Mining Area ◽

Coal Bed ◽

Coal Seams ◽

Acid Sensitivity ◽

Qinshui Basin ◽

Acid Fracturing ◽

Well Production ◽

Macro Scale

The reserves of Coalbed Methane (CBM) in Qinshui Basin are quite promising, but the outputs from CBM wells are quite small even after massive hydraulic fracturing. Herein the fracture system with #3 and #15 coal seams in Qinshui basin was analyzed, and it was found that both of the macro-scale fractures and micro-scale fractures are filled with clay and carbonate minerals, which explains the low productivity of CBM wells after conventional hydraulic fracturing. Acid fracturing has long been an effective method for carbonate gas reservoir to improve the gas well production. However, there were few reports about the application of acid fracturing in coal bed methane field. Based on the mineral identification and acid sensitivity test, the feasibility of acid fracturing demonstrated that the acid does more help than damage to increase the permeability of coal seams in Qinshui basin. Onsite operations have shown that acid fracturing is applicable for the CBM wells in Jincheng Mining Area. It was also observed from the microseismic survey that when applying the acid fracturing treatment, the stimulated reservoir area depends on the acid volume pumped in the first stage, which is crucial to the success of the stimulation. Evaluación piloto de fractura ácida en depósitos de gas metano de carbón en el suroeste de la cuenca Qinshui, China ResumenLas reservas de gas metano de carbón (CBM, del inglés Coalbed Methane) en la cuenca Qinshui son más que prometedoras, pero la producción en los pozos es muy pequeña, incluso después de fracturas hidráulicas masivas. En este trabajo se analizaron los sistemas de fractura de las vetas de carbón #3 y #15 de la cuenca Qinshui y se encontró que tanto las fracturas a macroescala como aquellas a microescala están cubiertas con arcillas y minerales carbonatos, lo que explica la baja productividad de los pozos de gas metano de carbón después de la fractura hidráulica convencional. La fractura ácida ha sido un método efectivo en los depósitos de gas carbonato para mejorar la producción en el pozo de gas. Sin embargo, existen pocos informes sobre la aplicación de la fractura ácida en el campo del gas metano de carbón. De acuerdo con la identificación mineral y las pruebas de sensibilidad ácida, la factibilidad de la fractura ácida demostró que el ácido es reparador en el incremento de la permeabilidad en las vetas de carbón de la cuenca Qinshui. Las operaciones in situ han demostrado que la fractura ácida es aplicable para los pozos de gas metano de carbón en el área minera de Jincheng. También se observó en el sondeo microsísmico que cuando se aplica un tratamiento de fractura ácida, el área del depósito estimulada depende del volumen de ácido bombeado en primera instancia, lo que es determinante en el éxito de la estimulación.

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Evaluation of the Geochemical Characteristics and Exploitation Potential of Produced Water from Coalbed Methane Wells in Eastern Yunnan, China

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2021.18731 ◽

2021 ◽

Vol 21 (1) ◽

pp. 591-598

Author(s):

Mingyang Du ◽

Caifang Wu ◽

Shasha Zhang ◽

Xiaolei Liu

Keyword(s):

Coal Seam ◽

Trace Element ◽

Coalbed Methane ◽

Element Concentration ◽

Produced Water ◽

Trace Element Concentration ◽

Surrounding Rock ◽

Geochemical Characteristics ◽

Drainage Time

Based on the analysis of the geochemical characteristics of the produced water from coalbed methane wells in eastern Yunnan, the effects of the water-rock interactions on the produced water were discussed, and the mining potential of each of the four wells was evaluated. The results show that with the increase in drainage time, the Na+ and Cl− concentrations decrease while the HCO−3 concentration increases. The produced water from the two wells in the Enhong Block shows D drift characteristics, while that of the two wells in the Laochang Block shows O drift characteristics. The order of the produced water affected by the surrounding rock is D-1 well > M-1 well > D-2 well > M-2 well, and the order of the produced water influenced by the coal seam is D-1 well > D-2 well > M-1 well > M-2 well. According to the variation in the As trace element concentration, it is inferred that in the four coalbed methane wells, the D-1 and D-2 wells have a greater exploitation potential than that of the M-1 and M-2 wells. On this basis, the influencing characterization parameters of the water-rock interactions on the produced water are established.

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

The Mountain Geologist ◽

10.31582/rmag.mg.54.3.203 ◽

2017 ◽

Vol 54 (3) ◽

pp. 203-221 ◽

Cited By ~ 9

Author(s):

Zell Peterman ◽

Joanna Thamke ◽

Kiyoto Futa ◽

Thomas Oliver

Keyword(s):

Membrane Filtration ◽

Meteoric Water ◽

Produced Water ◽

Major Ions ◽

Williston Basin ◽

Bakken Formation ◽

Rock Interaction ◽

Three Forks ◽

Western North Dakota ◽

Water Rock Interaction

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.

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Chemical and stable isotopic evidence for water/rock interaction and biogenic origin of coalbed methane, Fort Union Formation, Powder River Basin, Wyoming and Montana U.S.A.

International Journal of Coal Geology ◽

10.1016/j.coal.2008.05.002 ◽

2008 ◽

Vol 76 (1-2) ◽

pp. 76-85 ◽

Cited By ~ 69

Author(s):

C.A. Rice ◽

R.M. Flores ◽

G.D. Stricker ◽

M.S. Ellis

Keyword(s):

River Basin ◽

Coalbed Methane ◽

Powder River Basin ◽

Union Formation ◽

Rock Interaction ◽

Biogenic Origin ◽

Isotopic Evidence ◽

Stable Isotopic ◽

Fort Union Formation ◽

Water Rock Interaction

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A Laboratory Study of the Impact of Reinjecting Flowback Fluids on Formation Damage in the Marcellus Shale

SPE Journal ◽

10.2118/195336-pa ◽

2020 ◽

Vol 25 (02) ◽

pp. 788-799 ◽

Cited By ~ 3

Author(s):

Lifu Zhang ◽

Michael Tice ◽

Berna Hascakir

Keyword(s):

Hydraulic Fracturing ◽

Water Samples ◽

Produced Water ◽

Marcellus Shale ◽

Reservoir Rock ◽

Formation Damage ◽

Rock Interaction ◽

Flowback Water ◽

Rock Samples ◽

Water Rock Interaction

Summary Reuse of flowback water in hydraulic fracturing is usually used by industry to reduce consumption, transportation, and disposal cost of water. However, because of complex interactions between injected water and reservoir rocks, induced fractures may be blocked by impurities carried by flowback and mineral precipitation by water/rock interactions, which causes formation damage. Therefore, knowledge of flowback water/rock interactions is important to understand the changes within the formation and effects on hydraulic fracturing performance. This study focuses on investigating flowback water/rock interactions during hydraulic fracturing in Marcellus Shale. Simple deionized water (DI)/rock interactions and complicated flowback water/rock interactions were studied under static and dynamic conditions. In static experiments, crushed reservoir rock samples were exposed to water for 3 weeks at room condition. In the dynamic experiment, continuous water flow interacted with rock samples through the coreflooding experimental system for 3 hours at reservoir condition. Before and after experiments, rock samples were characterized to determine the change on the rock surfaces. Water samples were analyzed to estimate the particle precipitation tendency and potential to modify flow pathway. Surface elemental concentrations, mineralogy, and scanning electron microscope (SEM) images of rock samples were characterized. Ion contents, particle size, total dissolved solids (TDS), and zeta-potential in the water samples were analyzed. After flowback water/rock interaction, the surface of the rock sample shows changes in the compositions and more particle attachment. In produced water, Na, Sr, and Cl concentrations are extremely high because of flowback water contamination. Water parameters show that produced water has the highest precipitation tendency relative to all water samples. Therefore, if flowback water without any treatment is reused in hydraulic fracturing, formation damage is more likely to occur from blockage of pores. Flowback water management is becoming very important due to volumes produced in every hydraulic fracturing operation. Deep well injection is no longer a favorable option because it results in disposal of high volumes of water that cannot be used for other purposes. A second option is the reuse of waste water for fracturing purposes, which reduces freshwater use significantly. However, the impurities present in flowback water may deteriorate the fracturing job and reduce or block the hydraulic fracturing apertures. This study shows that a simple filtration process applied to the flowback water allows for reinjection of the flowback water without further complication to the water/rock interaction, and does not cause significant formation damage in the fractures.

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