CO_(2) huff-n-puff shows great potential to promote shale oil recovery after primary depletion.However,the extracting process of shale oil residing in different types of pores induced by the injected CO_(2) remains un...CO_(2) huff-n-puff shows great potential to promote shale oil recovery after primary depletion.However,the extracting process of shale oil residing in different types of pores induced by the injected CO_(2) remains unclear.Moreover,how to saturate shale core samples with oil is still an experimental challenge,and needs a recommended procedure.These issues significantly impede probing CO_(2) huff-n-puff in extracting shale oil as a means of enhanced oil recovery(EOR)processes.In this paper,the oil saturation process of shale core samples and their CO_(2) extraction response with respect to pore types were investigated using online T1-T2nuclear magnetic resonance(NMR)spectroscopy.The results indicated that the oil saturation of shale core samples rapidly increased in the first 16 days under the conditions of 60℃and 30 MPa and then tended to plateau.The maximum oil saturation could reach 46.2%after a vacuum and pressurization duration of 20 days.After saturation,three distinct regions were identified on the T1-T2NMR spectra of the shale core samples,corresponding to kerogen,organic pores(OPs),and inorganic pores(IPs),respectively.The oil trapped in IPs was the primary target for CO_(2) huff-n-puff in shale with a maximum cumulative oil recovery(COR)of 70%original oil in place(OOIP)after three cycles,while the oil trapped in OPs and kerogen presented challenges for extraction(COR<24.2%OOIP in OPs and almost none for kerogen).CO_(2) preferentially extracted the accessible oil trapped in large IPs,while due to the tiny pores and strong affinity of oil-wet walls,the oil saturated in OPs mainly existed in an adsorbed state,leading to an insignificant COR.Furthermore,COR demonstrated a linear increasing tendency with soaking pressure,even when the pressure noticeably exceeded the minimum miscible pressure,implying that the formation of a miscible phase between CO_(2) and oil was not the primary drive for CO_(2) huff-n-puff in shale.展开更多
REVO?is a dynamic measuring head and probe system,which is designed and applied in orthogonal coordinatemeasuring machines(CMMs)to maximize measurement throughput whilst maintaining high system accuracy.A calibration ...REVO?is a dynamic measuring head and probe system,which is designed and applied in orthogonal coordinatemeasuring machines(CMMs)to maximize measurement throughput whilst maintaining high system accuracy.A calibration approachto the stylus deformation of REVO head is proposed and the scale value of each CMM axis is separated from the limiteddata returned from the measuring system according to the application of REVO head in non-orthogonal CMM.Experimentsshow that the calibration method presented and extraction of scale value are of effectiveness and correctness.Results demonstratethat the maximum measurement error has decreased from0.2021mm to0.0009mm and the variation of scale value ofeach CMM axis is two orders lower after the stylus deformation is compensated.展开更多
基金the financial support of National Key Research and Development Program of China(2023YFE0120700)National Natural Science Foundation of China(52274041)Distinguished Young Sichuan Science Scholars(2023NSFSC1954)。
文摘CO_(2) huff-n-puff shows great potential to promote shale oil recovery after primary depletion.However,the extracting process of shale oil residing in different types of pores induced by the injected CO_(2) remains unclear.Moreover,how to saturate shale core samples with oil is still an experimental challenge,and needs a recommended procedure.These issues significantly impede probing CO_(2) huff-n-puff in extracting shale oil as a means of enhanced oil recovery(EOR)processes.In this paper,the oil saturation process of shale core samples and their CO_(2) extraction response with respect to pore types were investigated using online T1-T2nuclear magnetic resonance(NMR)spectroscopy.The results indicated that the oil saturation of shale core samples rapidly increased in the first 16 days under the conditions of 60℃and 30 MPa and then tended to plateau.The maximum oil saturation could reach 46.2%after a vacuum and pressurization duration of 20 days.After saturation,three distinct regions were identified on the T1-T2NMR spectra of the shale core samples,corresponding to kerogen,organic pores(OPs),and inorganic pores(IPs),respectively.The oil trapped in IPs was the primary target for CO_(2) huff-n-puff in shale with a maximum cumulative oil recovery(COR)of 70%original oil in place(OOIP)after three cycles,while the oil trapped in OPs and kerogen presented challenges for extraction(COR<24.2%OOIP in OPs and almost none for kerogen).CO_(2) preferentially extracted the accessible oil trapped in large IPs,while due to the tiny pores and strong affinity of oil-wet walls,the oil saturated in OPs mainly existed in an adsorbed state,leading to an insignificant COR.Furthermore,COR demonstrated a linear increasing tendency with soaking pressure,even when the pressure noticeably exceeded the minimum miscible pressure,implying that the formation of a miscible phase between CO_(2) and oil was not the primary drive for CO_(2) huff-n-puff in shale.
基金National Natural Science Foundation of China(No.51375338)
文摘REVO?is a dynamic measuring head and probe system,which is designed and applied in orthogonal coordinatemeasuring machines(CMMs)to maximize measurement throughput whilst maintaining high system accuracy.A calibration approachto the stylus deformation of REVO head is proposed and the scale value of each CMM axis is separated from the limiteddata returned from the measuring system according to the application of REVO head in non-orthogonal CMM.Experimentsshow that the calibration method presented and extraction of scale value are of effectiveness and correctness.Results demonstratethat the maximum measurement error has decreased from0.2021mm to0.0009mm and the variation of scale value ofeach CMM axis is two orders lower after the stylus deformation is compensated.
