China
Africa
Explore chapters and articles related to this topic
Hydraulic Fracking:The Process
Published in Frank R. Spellman, Hydraulic Fracturing Wastewater, 2017
As shown in Figure 2.4, hydraulic fracturing involves the pumping of fracturing fluid into a formation at a calculated, predetermined rate with enough pressure to generate fractures or cracks in the target formation. For shale gas development, fracture fluids are primarily water-based fluids mixed with additives that help the water to carry sand (or other material) proppant into the fractures. The proppant is needed to keep the fractures open when the pumping of fluid has stopped. When the fracture has initiated, additional fluids are pumped into the wellbore to continue the development of the fracture and to carry the proppant deeper into the formation. The additional fluids are needed to maintain the downhole pressure necessary to accommodate the increasing length of opened fractures in the formation. Each rock formation has inherent natural variability resulting in different fracture pressures for different formations. The process of designing hydraulic fracture treatments requires identifying properties of the target formation, including fracture pressure, and the desired length of fractures. The following discussion addresses some of the processes involved in the design of a hydraulic fracture stimulation of a shale gas formation.
Hydraulic Fracturing from the Groundwater Perspective
Published in M. Thangarajan, Vijay P. Singh, Groundwater Assessment, Modeling, and Management, 2016
Ruth M. Tinnacher, Dipankar Dwivedi, James E. Houseworth, Matthew T. Reagan, William T. Stringfellow, Charuleka Varadharajan, Jens T. Birkholzer
Traditional hydraulic fracturing induces fractures by injecting fluid into the well until the pressure exceeds the threshold for fracturing. The induced fractures emanate from the well into the reservoir and provide a high-permeability pathway from the formation to the well. One of the goals of the fracturing operation is to only fracture rock within the target reservoir; if the hydraulic fracturing strays out of the low-permeability target zone, there will be a "short-circuiting" effect, as more permeable units will contribute to production fluids. During portions of a hydraulic fracture treatment, "proppant" (natural sand or manufactured ceramic grains) is generally pumped in the frac fluid to prop the fracture(s) open, to maintain fracture conductivity after the treatment is completed, and the well is put on production. The effective stress imposed on a fracture plane and the proppant within the fracture is the total stress perpendicular to the fracture plane minus the pore pressure within the fracture. The use of proppant becomes particularly important for maintaining fracture permeability as formation fluids, a load-supporting element of formation strength, are removed by production. The creation of a highly permeable fracture network allows for the effective drainage of a much larger volume of low-permeability rock, and thus increases the hydrocarbon flow rates and total recovery.
Preliminary assessment of water-supply availability with regard to potential shale-gas development in the Karoo region of South Africa
Published in Jude Cobbing, Shafick Adams, Ingrid Dennis, Kornelius Riemann, Assessing and Managing Groundwater in Different Environments, 2013
The fluid injected into the rock typically comprises a slurry of water, proppants and chemical additives. Additionally, gels, foams, and compressed gases, including nitrogen, carbon dioxide and air can be injected. Types of proppant include silica sand, resin-coated sand and man-made ceramics. Chemical additives are selected to suit the specific geological situation, protect the well and improve its operation. Typically the fracking fluid comprises 90% water, 9.5% proppant and 0.5% chemicals. The chemicals may consist of up to 13 classes of additives (proppant excluded). The composition of the fracking fluid used may vary from one geological basin or formation to another or from one area to another in order to meet the specific needs of each operation, but the range of additive types available for potential use remains the same. There are a number of different products for each additive type; however, only one product of each type is typically used in any given fracking job. The selection may be driven by the formation and potential interactions between additives. Additionally, not all additive types will be used in every fracking job.
Preparation and performance study of coated sand fracturing proppants based on three of resin
Published in Petroleum Science and Technology, 2023
Xiaohong Wei, Ruiyun Yang, Conghui Liu, Tian Yang, Yiping Pu
The main proppants used in the fracturing process are quartz sand, ceramsite proppant, and resin film proppant, where quartz sand and ceramsite proppant are mainly utilized (Yang et al. 2009; Qiu et al. 2012; Wang et al. 2016; Shokouhi et al. 2019). Quartz sand is primarily used in fracturing shallow, low-closed pressure wells (Revil 2001; Karner et al. 2003). Ceramsite is primarily used in medium-deep blooming fracturing processes (Jia et al. 2014). Although ceramsite solves the low-strength problem of quartz sand, it has high density, high cost, and construction (Liang et al. 2016). Owing to these high risk factors, it is difficult to meet the requirements of the growing fracturing technology. The resin-coated proppant combines the advantages of quartz sand and ceramsite, is relatively convenient to use, and has high conductivity. Resin-coated proppant can be used not only for fracturing support, but also for preventing sand formation in geological formations and reducing proppant back (Mcdaniel 2002; Todd 2004; Zoveidavianpoor and Gharibi 2015; Gomez, Alexander, and Barron 2016). The proppant is a critical material in fracturing technology; thus, improving its performance is critical for improving the success rate of fracturing and significantly increasing oil production yield (Shokir and Al-Quraishi 2009; Kayumov et al. 2014; Qian et al. 2015; Osiptsov 2017). Research and development to produce a low-cost, high-performance coated sand proppant is important for improving the oil extraction rate and production.
Experimental study on replacing ceramsite with quartz sand in hydraulic fracturing
Published in Petroleum Science and Technology, 2022
Yang Che, Zhongwei Huang, Ruiyue Yang, Zhao Zhang, Chengyu Hui
Hydraulic fracturing is a technology which is widely applied in the oil and gas industry. In the 1940s, the engineer found that the fracture wouldn’t keep open without proppant. Since then, much more proppant had been injected into the fracture. The most commonly used proppant includes three types, quartz sand, ceramsite, and coated-sand. In general thinking, quartz sand fits for closure pressure lower than 28 MPa, while coated-sand fits for 52 MPa, and ceramsite can resist the stress up to 69 MPa. If the proppant is unsuitable, the closure pressure will make proppant crush seriously and then reduce the fracture permeability observably. Therefore, its crushing law is known as the key for hydraulic fracturing operation. Extensive research has been done to study the crushing law of proppant and the effect on conductivity.
Salt-tolerant and instant friction reducer for slickwater fracturing stimulation based on dispersion polymerization
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Fu Chen, Dai Li, Zihan Liao, Yu Den, Lin Zhang, Heng Wang
Figure 7 displays that FRe increases with varied flow rate at a fixed test diameter, and achieves the optimum FRe at 40 L/min considering the highest pumping efficiency. As the flow rate continues to increase, FRe does not significantly increase but additional energy consumption occurs. The flow rate increase indicated the increase in the degree of turbulence inside the pipe, which causes DPFR chains to stretch considerably at high-bulk velocity. FRe correlates with the hydrodynamic radius for friction reduction (L et al. 1990), and fully stretched polymers provide effective hydrodynamic volume to absorb energy from the turbulent eddies and dissipates it as a result of friction reduction (G E. Gadd 1965). Although a suitable dosage and flow rate are necessary to stop proppant from settling out of slickwater and conduct fracturing stimulation, the economic costs of the raw materials of the friction reducer and pumping energy should be considered.