Recovery rates of fracturing fluids and provenance of produced water from hydraulic fracturing of Silurian Qusaiba hot shale, northern Saudi Arabia, with implications on fracture network

AAPG Bulletin ◽  
2016 ◽  
Vol 100 (06) ◽  
pp. 917-941 ◽  
Author(s):  
Peter Birkle
2015 ◽  
Vol 12 (3) ◽  
pp. 286 ◽  
Author(s):  
Madeleine E. Payne ◽  
Heather F. Chapman ◽  
Janet Cumming ◽  
Frederic D. L. Leusch

Environmental context Hydraulic fracturing fluids, used in large volumes by the coal seam gas mining industry, are potentially present in the environment either in underground formations or in mine wastewater (produced water). Previous studies of the human health and environmental effects of this practice have been limited because they use only desktop methods and have not considered combined mixture toxicity. We use a novel in vitro method for toxicity assessment, and describe the toxicity of a hydraulic fracturing fluid on a human gastrointestinal cell line. Abstract Hydraulic fracturing fluids are chemical mixtures used to enhance oil and gas extraction. There are concerns that fracturing fluids are hazardous and that their release into the environment – by direct injection to coal and shale formations or as residue in produced water – may have effects on ecosystems, water quality and public health. This study aimed to characterise the acute cytotoxicity of a hydraulic fracturing fluid using a human gastrointestinal cell line and, using this data, contribute to the understanding of potential human health risks posed by coal seam gas (CSG) extraction in Queensland, Australia. Previous published research on the health effects of hydraulic fracturing fluids has been limited to desktop studies of individual chemicals. As such, this study is one of the first attempts to characterise the toxicity of a hydraulic fracturing mixture using laboratory methods. The fracturing fluid was determined to be cytotoxic, with half maximal inhibitory concentrations (IC50) values across mixture variations ranging between 25 and 51mM. When used by industry, these fracturing fluids would be at concentrations of over 200mM before injection into the coal seam. A 5-fold dilution would be sufficient to reduce the toxicity of the fluids to below the detection limit of the assay. It is unlikely that human exposure would occur at these high (‘before use’) concentrations and likely that the fluids would be diluted during use. Thus, it can be inferred that the level of acute risk to human health associated with the use of these fracturing fluids is low. However, a thorough exposure assessment and additional chronic and targeted toxicity assessments are required to conclusively determine human health risks.


2021 ◽  
Author(s):  
Mustafa Ahmed Alkhowaildi ◽  
Mohamed Mahmoud ◽  
Mohammed Abdullah Bataweel ◽  
Bassam Tawabini

Abstract Amid the rise in energy demand over recent years, natural gas from tight reservoirs has been targeted abundantly around the globe by different oil operators. Hydraulic fracturing technology has been instrumental in the successful exploitation of energy from tight formations. The process is associated with enormous usage of water. Hydraulic fracturing requires as little as 500,000 gallons of freshwater, and up to 6 million gallons per well depending on the type of well and the number of stages treated. Now operators, as well as service companies worldwide, have shown a desire to use produced water in field operations to enhance economics and reduce their environmental footprint. Reusing produced water in field operations appears to be a win-win proposition by transforming the industry's biggest waste product into a resource. This paper highlights the recent findings in published articles about formulating a fracturing fluid from produced water as a base fluid. The rheological properties and fluid performance requirements, such as proppant carrying capacity, mixing, fluid efficiency, ability to crosslink and break, and cleanup after treatment, will be evaluated in detail. This paper identified the critical parameters associated with high TDS fluids (produced water) such as pH, hydration time, ionic strength, and suspended solids, collected the corresponding optimal ranges for these parameters in laboratory tests, and reported some of the validity of the findings under actual conditions in field trials around the world. Most studies demonstrated the feasibility of using untreated produced water as a base fluid for crosslinked gel-based hydraulic fracturing. Through adjusting the hydration time, the gel loading, and the amount of breakers applied, it is conceivable that crosslinked gels with optimal rheological characteristics can be formulated with untreated produced water. Multiple generations of guar- and CMHPG-based crosslinked fracturing fluids, developed with 100% untreated produced water, exhibited optimal viscosities exceeding 200 cp at 40 s−1 for at least 60 minutes. The ability to provide fracturing fluids with high-salinity produced water can be a successful water conservation approach and an attractive solution for enhancing operation economics. Some studies indicated that using produced water can be better than freshwater because the produced water is more compatible with the reservoir and may be less likely to cause conditions such as salinity shock, which can damage the formation. More studies are needed to understand the associated technical challenges further.


2021 ◽  
Author(s):  
Carl Harman ◽  
Michael McDonald ◽  
Paul Short ◽  
William Ott

Abstract The use of freshwater, near freshwater, or treated water in hydraulic fracturing represents an ever-increasing cost in the Permian Basin. Environmental concerns add to the pressure to develop methods to use significantly higher volumes of produced water in hydraulic fracture fluids. To solve the challenge of viscosifying untreated, high total dissolved solids water a move was made away from organic-based viscosifiers to silica-based technology. Fumed silica is highly effective as a viscosifier for high-density brines that has demonstrated excellent low-end rheology, exceptional suspending ability, and a nominal filter cake. However, the high cost of fumed silica and operational challenges have precluded commercial adoption. This paper describes thatsimilar rheology is achievable at a fraction of the cost using a silica gel. The focus of the paper is on the field trials in West Texas where untreated produced water was viscosified with silica gel and run as alternatives to a standard 20 lb/Mgal crosslinked guar fluid made with fresh water. Low cost and operational efficiencies were obtained bypreparingthe silica gel on-location using standard and readily available hydraulic fracturing equipment. Procedures for making the silica gel-based frac fluid were similar to those of making a crosslinked guar fluid. Field trials have demonstrated that silica-gel carries high loadings of 20/40 mesh sand even at low pump rates. Production data from the trials has varied from exceeding expectations to being similar to existing production results.On a chemical cost basis, silica gel is comparable to a borate-cross-linked guar frac fluid. The economics tip very much in favor of silica gel when factoring in the savings using untreated produced water.


2013 ◽  
Vol 47 (22) ◽  
pp. 13141-13150 ◽  
Author(s):  
Arvind Murali Mohan ◽  
Angela Hartsock ◽  
Kyle J. Bibby ◽  
Richard W. Hammack ◽  
Radisav D. Vidic ◽  
...  

2019 ◽  
Vol 21 (10) ◽  
pp. 1777-1786 ◽  
Author(s):  
Brandon C. McAdams ◽  
Kimberly E. Carter ◽  
Jens Blotevogel ◽  
Thomas Borch ◽  
J. Alexandra Hakala

Chemical changes to hydraulic fracturing fluids within fractured unconventional reservoirs may affect hydrocarbon recovery and, in turn, the environmental impact of unconventional oil and gas development.


Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1783
Author(s):  
Klaudia Wilk-Zajdel ◽  
Piotr Kasza ◽  
Mateusz Masłowski

In the case of fracturing of the reservoirs using fracturing fluids, the size of damage to the proppant conductivity caused by treatment fluids is significant, which greatly influence the effective execution of hydraulic fracturing operations. The fracturing fluid should be characterized by the minimum damage to the conductivity of a fracture filled with proppant. A laboratory research procedure has been developed to study the damage effect caused by foamed and non-foamed fracturing fluids in the fractures filled with proppant material. The paper discusses the results for high quality foamed guar-based linear gels, which is an innovative aspect of the work compared to the non-foamed frac described in most of the studies and simulations. The tests were performed for the fracturing fluid based on a linear polymer (HPG—hydroxypropyl guar, in liquid and powder form). The rheology of nitrogen foamed-based fracturing fluids (FF) with a quality of 70% was investigated. The quartz sand and ceramic light proppant LCP proppant was placed between two Ohio sandstone rock slabs and subjected to a given compressive stress of 4000–6000 psi, at a temperature of 60 °C for 5 h. A significant reduction in damage to the quartz proppant was observed for the foamed fluid compared to that damaged by the 7.5 L/m3 natural polymer-based non-foamed linear fluid. The damage was 72.3% for the non-foamed fluid and 31.5% for the 70% foamed fluid, which are superior to the guar gum non-foamed fracturing fluid system. For tests based on a polymer concentration of 4.88 g/L, the damage to the fracture conductivity by the non-foamed fluid was 64.8%, and 26.3% for the foamed fluid. These results lead to the conclusion that foamed fluids could damage the fracture filled with proppant much less during hydraulic fracturing treatment. At the same time, when using foamed fluids, the viscosity coefficient increases a few times compared to the use of non-foamed fluids, which is necessary for proppant carrying capacities and properly conducted stimulation treatment. The research results can be beneficial for optimizing the type and performance of fracturing fluid for hydraulic fracturing in tight gas formations.


RSC Advances ◽  
2021 ◽  
Vol 11 (37) ◽  
pp. 22517-22529
Author(s):  
Shuhao Liu ◽  
Yu-Ting Lin ◽  
Bhargavi Bhat ◽  
Kai-Yuan Kuan ◽  
Joseph Sang-II Kwon ◽  
...  

Viscosity modifying agents are one of the most critical components of hydraulic fracturing fluids, ensuring the efficient transport and deposition of proppant into fissures.


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