Experimental study of the stimulating mechanism of shut-in after hydraulic fracturing in unconventional oil reservoirs

Asphaltene Precipitation and Deposition during Nitrogen Gas Cyclic Miscible and Immiscible Injection in Eagle Ford Shale and Its Impact on Oil Recovery

“…Unconventional resources, like shale reservoirs, are widely recognized for their extremely low permeability and porosity . Despite the fact that multistage hydraulic fracturing and horizontal well drilling techniques are used to extract the remaining oil from such reservoirs, only 4–6% of the trapped oil can be extracted, and the oil production drops after a few months, attributing to the ultralow permeability. − Water injection is also one of the suitable strategies for increasing oil recovery from conventional reservoirs; nevertheless, due to weak injectivity, insufficient sweep potency, and clay swelling concerns, this approach is not the ideal solution for tight reservoirs. , Cyclic gas injection outperforms gas flooding methods in terms of enhancing oil recovery, mainly in ultratight reservoirs. , The total organic carbon (TOC) is the most important influencing parameter on gas injection in tight reservoirs because kerogen makes the surface of the pore oil-wet, making the oil inside challenging to extract . Due to the combination of multiphase fluids (i.e., gas, oil, condensate, and water) and scales, multiphase flow production can create a number of challenges including wax and asphaltene deposition, hydrate formation, slugging, and emulsions .…”

Experimental Investigation of Asphaltene Deposition and Its Impact on Oil Recovery in Eagle Ford Shale during Miscible and Immiscible CO2 Huff-n-Puff Gas Injection

“…Unconventional resources, such as shale reservoirs, are well-known to have ultra-small permeability and very low porosity . Only 4–6% of the trapped oil may be retrieved using multi-stage hydraulic fracturing and horizontal well drilling methods, − and oil production decreases after months attributable to the ultra-small permeability of such reservoirs. − The water flooding technique is one applicable method that can increase oil recovery (OR) from conventional reservoirs; however, this technique is not the optimal choice for tight reservoirs due to their poor injectivity, poor sweep potency, and clay swelling issues. , Gas injection has become a widespread technology that improves oil production in unconventional reservoirs in the United States and could be the best reliable method to unlock the remaining oil percentage . Huff-n-puff gas injection has a more advantageous impact in increasing OR compared to gas flooding techniques, especially in ultra-tight reservoirs with the matrix permeability under 0.001 mD. , Because kerogen renders the surface of the pores oil-wet, extracting the oil from inside tight reservoirs is restricted by the presence of a high total organic carbon (TOC) .…”

Fracture propagation induced by hydraulic fracturing using microseismic monitoring technology: Field test in CBM wells in Zhengzhuang region, Southern Qinshui Basin, China

“…Hydraulic fracturing technique is one of the most important measures to artificially increase the production of oil and gas reserves (Li et al, 2019a;Liu et al, 2021). In order to improve the productivity of oil and gas, North American scientists firstly proposed a new hydraulic fracturing technique, stimulated reservoir volume (SRV), based on the physical characteristics of the reservoir and traditional hydraulic fracturing (Mu et al, 2014).…”