Hydraulic fracturing is a critical technology for the economic development of unconventional oil and gas reservoirs.The main factor influencing fracture propping and reservoir stimulation effect is proppant performanc...Hydraulic fracturing is a critical technology for the economic development of unconventional oil and gas reservoirs.The main factor influencing fracture propping and reservoir stimulation effect is proppant performance.The increasing depth of fractured oil and gas reservoirs is causing growing difficulty in hydraulic fracturing.Moreover,the migration of conventional proppants within the fracture is always limited due to small fracture width and rigid proppant structure.Thus,proppants with good transportation capacity and fracture propping effects are needed.First,a novel self-generated proppant based on toughened low-viscosity and low-density epoxy resin was developed to satisfy this demand.Then,proppant performances were evaluated.Low-viscosity and low-density epoxy resin was generated when the thiol-ene click chemical reaction product of eugenol and 1-thioglycerol reacts with the epichlorohydrin.Then,the resin was toughened with graphite particles to increase its compressive strength from50.8 to 72.1 MPa based on micro-cracking mechanism and crazing-nail anchor mechanism.The adduct of diethylene triamine and butyl glycidyl ether and the Si O2 nanoparticles were treated as the curing agent and emulsifier respectively to form the emulsion.The emulsion is transformed into solid particles of various sizes within a reservoir to prop the fracture.Evaluation shows good migration capacity of this self-generated proppant due to the low density of epoxy resin.展开更多
The main function of traditional proppants is to provide and maintain conductive fractures during well production where proppants should meet closure stress requirement and show resistance to diagenesis under downhole...The main function of traditional proppants is to provide and maintain conductive fractures during well production where proppants should meet closure stress requirement and show resistance to diagenesis under downhole conditions.Many different proppants have been developed in the oil&gas industry,with various types,sizes,shapes,and applications.While most proppants are simply made of silica or ceramics,advanced proppants like ultra-lightweight proppant is also desirable since it reduces proppant settling and requires low viscosity fluids to transport.Additionally,multifunctional proppants may be used as a crude way to detect hydraulic fracture geometry or as matrices to slowly release downhole chemical additives,besides their basic function of maintaining conductive hydraulic fractures.Different from the conventional approach where proppant is pumped downhole in frac fluids,a revolutionary way to generate in-situ spherical proppants has been reported recently.This paper presents a comprehensive review of over 100 papers published in the past several decades on the subject.The objectives of this review study are to provide an overview of current proppant technologies,including different types,compositions,and shapes of proppants,new technologies to pump and organize proppants downhole such as channel fracturing,and also in-situ proppant generation.Finally,the paper sheds light on the current challenges and emphasizes needs for new proppant development for unconventional resources.展开更多
基金financial support of the National Natural Science Foundation of China(Grant No.52074332)express their gratitude to project ZR2020YQ36 supported by Shandong Provincial Science Fund for Excellent Young Scholars+1 种基金the Major Scientific and Technological Projects of CNPC under Grand ZD 2019-184-002-003CNPC Innovation Found(Grant No.2021DQ02-1006)。
文摘Hydraulic fracturing is a critical technology for the economic development of unconventional oil and gas reservoirs.The main factor influencing fracture propping and reservoir stimulation effect is proppant performance.The increasing depth of fractured oil and gas reservoirs is causing growing difficulty in hydraulic fracturing.Moreover,the migration of conventional proppants within the fracture is always limited due to small fracture width and rigid proppant structure.Thus,proppants with good transportation capacity and fracture propping effects are needed.First,a novel self-generated proppant based on toughened low-viscosity and low-density epoxy resin was developed to satisfy this demand.Then,proppant performances were evaluated.Low-viscosity and low-density epoxy resin was generated when the thiol-ene click chemical reaction product of eugenol and 1-thioglycerol reacts with the epichlorohydrin.Then,the resin was toughened with graphite particles to increase its compressive strength from50.8 to 72.1 MPa based on micro-cracking mechanism and crazing-nail anchor mechanism.The adduct of diethylene triamine and butyl glycidyl ether and the Si O2 nanoparticles were treated as the curing agent and emulsifier respectively to form the emulsion.The emulsion is transformed into solid particles of various sizes within a reservoir to prop the fracture.Evaluation shows good migration capacity of this self-generated proppant due to the low density of epoxy resin.
文摘The main function of traditional proppants is to provide and maintain conductive fractures during well production where proppants should meet closure stress requirement and show resistance to diagenesis under downhole conditions.Many different proppants have been developed in the oil&gas industry,with various types,sizes,shapes,and applications.While most proppants are simply made of silica or ceramics,advanced proppants like ultra-lightweight proppant is also desirable since it reduces proppant settling and requires low viscosity fluids to transport.Additionally,multifunctional proppants may be used as a crude way to detect hydraulic fracture geometry or as matrices to slowly release downhole chemical additives,besides their basic function of maintaining conductive hydraulic fractures.Different from the conventional approach where proppant is pumped downhole in frac fluids,a revolutionary way to generate in-situ spherical proppants has been reported recently.This paper presents a comprehensive review of over 100 papers published in the past several decades on the subject.The objectives of this review study are to provide an overview of current proppant technologies,including different types,compositions,and shapes of proppants,new technologies to pump and organize proppants downhole such as channel fracturing,and also in-situ proppant generation.Finally,the paper sheds light on the current challenges and emphasizes needs for new proppant development for unconventional resources.
