页岩压裂过程的连续时域电磁法动态监测试验（英文）
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摘要
页岩气开发水压过程中监测裂缝的空间展布对页岩气稳产高产并指导压裂至关重要。常规的时移地震、井间地震及微震监测不但成本高,监测效果显示周期长,且不能直观展示压裂液的平面和空间形态的动态变化。本试验研究首先对压裂液及压裂液充填的岩样进行了电性测试与分析,发现其具有极低阻与高极化特征,表明可控源电磁法进行页岩压裂过程的动态监测有着良好的电性基础。其次,基于试验区井震资料建立的地电模型,通过改变储层电性进行正演模拟,研究了电场分量的变化规律,提出了瞬变电磁法动态监测的归一化残差电阻率成像方法。最后,以时移电磁长偏移距瞬变电磁阵列法为手段,在我国南方涪陵页岩开发区水平压裂井上进行了连续时域电磁法动态监测试验。通过参研单位高度协同,采取了大功率与数百道阵列观测方式,获取了埋深在2800米处三个压裂段上方地面224个物理点近9个小时的电场时间序列数据。处理结果表明,该方法能有效观测到压裂液引起的电场信号变化。通过残差处理与电阻率成像,获取了储层改造过程的动态图像,结合地震、测井与水平井位的标定,解释了压裂液平面和空间展布,其结果对页岩气有效压裂与安全开采有重要指导意义,展示出连续时域电磁法在页岩气开发的压裂监测中有着广阔的应用前景。
Monitoring and delineating the spatial distribution of shale fracturing is fundamentally important to shale gas production. Standard monitoring methods, such as time-lapse seismic, cross-well seismic and micro-seismic methods, are expensive, timeconsuming, and do not show the changes in the formation with time. The resistivities of hydraulic fracturing fluid and reservoir rocks were measured. The results suggest that the injection fluid and consequently the injected reservoir are characterized by very low resistivity and high chargeability. This allows using of the controlled-source electromagnetic method(CSEM) to monitor shale gas hydraulic fracturing. Based on the geoelectrical model which was proposed according to the well-log and seismic data in the test area the change rule of the reacted electrical field was studied to account for the change of shale resistivity,and then the normalized residual resistivity method for time lapse processing was given. The time-domain electromagnetic method(TDEM) was used to continuously monitor the shale gas fracturing at the Fulin shale gas field in southern China. A high-power transmitter and multi-channel transient electromagnetic receiver array were adopted. 9 h time series of Ex component of 224 sites which were laid out on the surface and over three fracturing stages of a horizontal well at 2800 m depth was recorded. After data processing and calculation of the normalized resistivity residuals,the changes in the Ex signal were determined and a dynamic3 D image of the change in resistivity was constructed. This allows modeling the spatial distribution of the fracturing fluid. The model results suggest that TDEM is promising for monitoring hydraulic fracturing of shale.
Monitoring and delineating the spatial distribution of shale fracturing is fundamentally important to shale gas production. Standard monitoring methods, such as time-lapse seismic, cross-well seismic and micro-seismic methods, are expensive, timeconsuming, and do not show the changes in the formation with time. The resistivities of hydraulic fracturing fluid and reservoir rocks were measured. The results suggest that the injection fluid and consequently the injected reservoir are characterized by very low resistivity and high chargeability. This allows using of the controlled-source electromagnetic method(CSEM) to monitor shale gas hydraulic fracturing. Based on the geoelectrical model which was proposed according to the well-log and seismic data in the test area the change rule of the reacted electrical field was studied to account for the change of shale resistivity,and then the normalized residual resistivity method for time lapse processing was given. The time-domain electromagnetic method(TDEM) was used to continuously monitor the shale gas fracturing at the Fulin shale gas field in southern China. A high-power transmitter and multi-channel transient electromagnetic receiver array were adopted. 9 h time series of Ex component of 224 sites which were laid out on the surface and over three fracturing stages of a horizontal well at 2800 m depth was recorded. After data processing and calculation of the normalized resistivity residuals,the changes in the Ex signal were determined and a dynamic3 D image of the change in resistivity was constructed. This allows modeling the spatial distribution of the fracturing fluid. The model results suggest that TDEM is promising for monitoring hydraulic fracturing of shale.
引文
Albaric,J.,Oye,V.,Langet,N.,Hasting,M.,Lecomte,I.,Iranpour,K.,Messeiller,M.,and Reid,P.,2014.Monitoring of induced seismicity during the first geothermal reservoir stimulation at Paralana,Australia:,Geothermics,52,120-131.
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He,Z.,Hu,Z.,Gao,Y.,He,L.,Meng,C.,and Yang,L.,2015.Field test of monitoring gas reservoir development using time-lapse continuous electromagnetic profile method:Geophysics 80(2),WA127-WA134.
Hoversten,G.M.,Commer,M.,Haber,E.,and Schwarzbach,C.,2015.Hydro-frac monitoring using ground time domain electromagnetics:Geophysical Prospecting,63,1508-1526.
Hoversten,G.M.,Schwarzbach,C.,Haber,E.,Belliveau,P.,and Shekhtman,R.,2017,Borehole to surface electromagnetic monitoring of hydraulicfractures:6th International Symposium on ThreeDimensional Electromagnetics.Berkeley,California,USA,March 28-30.
Hu,W.,Yan,L.,Su,Z.,Zheng,R.and Strack,K,2008.Array TEM Sounding and Application for Reservoir Monitoring:.78th Ann.Internat.Mtg,SEG,Expanded Abstracts,.27(1),634-638
Macnae,J.,1987,Imaging quasi-layered conductive structures by simple processing of transient electromagnetic data:Geophysics,52(4),545-554.
Maxwell,S.E.,Cho,D.,Pope T.,Jones,M.,and Leonard,J.,2011,Enhanced reservoir characterization using hydraulic fracture microseismicity,Paper SPE140449 presented at the SPE Annual Technical Conference and Exhibition,Texas,USA,24-26January.2011.
Orange,A.,Key,K.,and Constable,S.,2009,The feasibility of reservoir monitoring using time-lapse marine CSEM:Geophysics,74(2),F21-f29.
Peacock,J.R.,Thiel,S.,Reid,p.,and Heinson,G.,2012.Magnetotelluric monitoring of a fluid injection:Example from an enhanced geothermal system:Geophysical Research Letters,39(18),L18.
Peacock,J.,Thiel,S.,Heinson,G.,and Reid,P.,2013.Time-lapse magnetotelluric monitoring of an enhanced geothermal system:Geophysics 78(3),B121-B130.
Peng R.H.,Hu,X.Y.,Liu,Y.X.,and He Z.X.,2012.The feasibility study of time-lapse two dimensional magnetotelluric for reservoir monitoring:Chinese Geophysical Society,2012,112.
Raiche,A.P.,and Gallagher,R.G.,1985.Apparent resistivity and diffusion velocity:Geophysics,50,1628-1633.
Rees,N.,Heinson,G.,and Krieger,L.,2016.Magnetotelluric monitoring of coal seam gas depressurization:Geophysics,81(6),E424-E431.
Rees,N.,Carter,S.,Heinson,G.,and Krieger,L.2016,Monitoring shale gas resources in the Cooper Basinusing magnetotellurics:Geophysics,81(6),A13-A16
Strack,K.M.,1992,Exploration with Deep Transient,Electromagnetics:Elsevier,373 pp.
Streich,R.,2016.Controlled-source electromagnetic approaches for hydrocarbon exploration and monitoring on land:Surveys in Geophysics,37(1),47-80.
Weckmann,U.,Ritter,O.,Haak,V.,2003.Images of the magnetoteluric apparent resistivity tensor:Geophysical Journal International,155(2),456-468.
Xie,X.B.,Zhou,L.,2016.The application of long offset transient electromagnetic method in the monitoring of residual oil:Oil Geophysical Prospecting,51(3),606-612.
Xu,D.,Hu,X.Y.,Shan,C.L.etc.,2016.Landslide monitoring in southwestern China via time-lapseelectrical resistivity tomography:Applied Geophysics,13(1),1-12.
Yan,L.J.,Yang,S.F.,Hu,W.B.,2001.Electromagnetic prospecting method and its application in carbonate area of South China:Petroleum Industry Press,Beijing.
Abdelfettah,Y.,Sailhac,E.,and Schill,H.,P.D.,2016.Continuous MT monitoring for small fluid injection volume at Rittershoffen Geophysical Project,northern Alsace France:23rd Electromagnetic Induction Workshop,Chiang Mai,Thailand.
He,Z.,Hu,Z.,Gao,Y.,He,L.,Meng,C.,and Yang,L.,2015.Field test of monitoring gas reservoir development using time-lapse continuous electromagnetic profile method:Geophysics 80(2),WA127-WA134.
Hoversten,G.M.,Commer,M.,Haber,E.,and Schwarzbach,C.,2015.Hydro-frac monitoring using ground time domain electromagnetics:Geophysical Prospecting,63,1508-1526.
Hoversten,G.M.,Schwarzbach,C.,Haber,E.,Belliveau,P.,and Shekhtman,R.,2017,Borehole to surface electromagnetic monitoring of hydraulicfractures:6th International Symposium on ThreeDimensional Electromagnetics.Berkeley,California,USA,March 28-30.
Hu,W.,Yan,L.,Su,Z.,Zheng,R.and Strack,K,2008.Array TEM Sounding and Application for Reservoir Monitoring:.78th Ann.Internat.Mtg,SEG,Expanded Abstracts,.27(1),634-638
Macnae,J.,1987,Imaging quasi-layered conductive structures by simple processing of transient electromagnetic data:Geophysics,52(4),545-554.
Maxwell,S.E.,Cho,D.,Pope T.,Jones,M.,and Leonard,J.,2011,Enhanced reservoir characterization using hydraulic fracture microseismicity,Paper SPE140449 presented at the SPE Annual Technical Conference and Exhibition,Texas,USA,24-26January.2011.
Orange,A.,Key,K.,and Constable,S.,2009,The feasibility of reservoir monitoring using time-lapse marine CSEM:Geophysics,74(2),F21-f29.
Peacock,J.R.,Thiel,S.,Reid,p.,and Heinson,G.,2012.Magnetotelluric monitoring of a fluid injection:Example from an enhanced geothermal system:Geophysical Research Letters,39(18),L18.
Peacock,J.,Thiel,S.,Heinson,G.,and Reid,P.,2013.Time-lapse magnetotelluric monitoring of an enhanced geothermal system:Geophysics 78(3),B121-B130.
Peng R.H.,Hu,X.Y.,Liu,Y.X.,and He Z.X.,2012.The feasibility study of time-lapse two dimensional magnetotelluric for reservoir monitoring:Chinese Geophysical Society,2012,112.
Raiche,A.P.,and Gallagher,R.G.,1985.Apparent resistivity and diffusion velocity:Geophysics,50,1628-1633.
Rees,N.,Heinson,G.,and Krieger,L.,2016.Magnetotelluric monitoring of coal seam gas depressurization:Geophysics,81(6),E424-E431.
Rees,N.,Carter,S.,Heinson,G.,and Krieger,L.2016,Monitoring shale gas resources in the Cooper Basinusing magnetotellurics:Geophysics,81(6),A13-A16
Strack,K.M.,1992,Exploration with Deep Transient,Electromagnetics:Elsevier,373 pp.
Streich,R.,2016.Controlled-source electromagnetic approaches for hydrocarbon exploration and monitoring on land:Surveys in Geophysics,37(1),47-80.
Weckmann,U.,Ritter,O.,Haak,V.,2003.Images of the magnetoteluric apparent resistivity tensor:Geophysical Journal International,155(2),456-468.
Xie,X.B.,Zhou,L.,2016.The application of long offset transient electromagnetic method in the monitoring of residual oil:Oil Geophysical Prospecting,51(3),606-612.
Xu,D.,Hu,X.Y.,Shan,C.L.etc.,2016.Landslide monitoring in southwestern China via time-lapseelectrical resistivity tomography:Applied Geophysics,13(1),1-12.
Yan,L.J.,Yang,S.F.,Hu,W.B.,2001.Electromagnetic prospecting method and its application in carbonate area of South China:Petroleum Industry Press,Beijing.