The Relationship of Ultra-Low Permeability Sandstone Aspect Ratio With Porosity, Permeability

Transcription

1 Advances in Peoeum Exoaion and Deveomen Vo. 7, No. 1, 01,. 7-1 DOI:.3968/j.aed ISSN 19-X [Pin] ISSN [Onine] The Reaionshi of Ua-Low Pemeabiiy Sandsone Asec Raio Wih Poosiy, Pemeabiiy WEI Haoguang [a],* ; MA Kun [b] ; YUE Xiang an [c] ; WANG Xinxin [d] [a] SINOPEC Reseach Insiue of Peoeum Engineeing, Beijing, China. [b] China Naiona Sofwae & Sevice Co., Ld., Beijing, China. [c] MOE Key Laboaoy of Peoeum Engineeing in China Univesiy of Peoeum, Beijing, China. [d] Engineeing Technoogy Bueau, Jiin Oified Comany, Songyuan Jiin, China. * Coesonding auho. Received 6 Seembe 013; acceed 8 Januay 01 Absac The ua-ow emeabiiy sandsone esevoi has age asec aio which significany infuences he mui-hase ecoaion chaaceisic. The aio coud be accuaey measued by ae-conoed mecuy oosimey, bu he esing echnoogy is exensive, ime-consuming and coeconaminaing. Thee is no a sime effecive mehod o descibe he asec aio. The oes of he ua-ow emeabiiy sandsone ae mainy conneced by he vey ong naow hoas, which coud be advanageousy simuaed by he comound caiay bundes mode. The anayica exessions of oosiy and emeabiiy abou majo oe sucue aamees ae esabished based on he mode fo he igh oous media. Afe soving he wo exessions, he eaionshi beween asec aio and aamee combinaion of oosiy, emeabiiy is obained fo he ua-ow emeabe sandsone. Then he eaion is fied in his aice using many evious ubished ae-conoed mecuy daa on comac sandsone and he eevance is song, which oves ha asec aio of igh ock is abe o be cacuaed wih is oosiy and emeabiiy. Key wods: Ua-ow emeabiiy sandsone; Asec aio; Poe; Thoa; Poosiy; Pemeabiiy Wei, H. G., Ma, K., Yue, X. A., & Wang, X. X. (01). The eaionshi of ua-ow emeabiiy sandsone asec aio wih oosiy, emeabiiy. Advances in Peoeum Exoaion and Deveomen, 7(1), 7-1. Avaiabe fom: URL: h:// ne/index.h/aed/aice/view/j.aed DOI: h://dx.doi.og/.3968/j.aed INTRODUCTION The oosiy sysem disibued as an ineconneced newok is made u of oes and hoas in a sedimenay ocks. Poes ae eaivey age nodes muuay conneced by hoas in he newok. A hoa is he consicion of minima coss seciona aea of a condui connecing one oe o anohe [1,]. Wih coninued gowh in he exoaion and deveomen of he ua-ow emeabiiy ( -3 μm ) sandsone hydocabon esevoi, eoeum geoscieniss and enginees ae inceasingy concened wih micoscoic hysica oey and mui-hase fuid fow. The ow-quaiy esevoi sand-ocks geneay have mico hoas, and asec aio defined as he aio of he oe size o he hoa size becomes vey age. Yang e a. [3] have eoed ha we oducion in Daqing s eihea oifieds is much owe han ha in Changqing oifieds even hough hei emeabiiies ae aoximaed, and he much age asec aio is one of he dominaing causes. Asec aio infuences mui-hase fuid disibuion and fow in oous media. Sna-off occus when he acceeaion of he non-weing hase, as i asses fom hoa o oe, is sufficien o beak he head of non-weing hase nea he oe/hoa ineface. Then he hase is isoaed and can ony engage in fow if econneced [,]. Wih newok mode simuaions and micocosmic exeimens, sna-off is he mos onounced mechanism of enaing esidua oi in wae-we ocks of age asec aio [6-8]. Lowe asec aios suess sna-off and caiay essue which esus in a moe efficien disacemen wih highe eaive emeabiiies and owe esidua sauaions [9,]. Mecuy injecion is he quaniaive measuemen mehod o deemine he asec aio, and hee ae wo exeimena modes of daa acquisiion in mecuy oosimey. The fis one, essue-conoed mecuy oosimey gives infomaion on hoa sizes ahe han on he oes behind he hoas [11-13]. The asec aio is no caabe of being measued accuaey. The second, ae- 7 Coyigh Canadian Reseach & Deveomen Cene of Sciences and Cuues

2 The Reaionshi of Ua-Low Pemeabiiy Sandsone Asec Raio Wih Poosiy, Pemeabiiy conoed mecuy oosimey is based on a echnique ha injecs mecuy ino a coe same a exemey ow aes. Mecuy successivey enes ino singe hoa and oe, and he exeimen ocess is quasi-saic. Monioing fucuaions in mecuy injecion essue can idenify hoa and oe [1]. Howeve, he highes essue of injecing mecuy is jus 6.0 MPa, and he coesonding hoa adius is 0.1 μm, hen hoas smae han 0.1μm and oes conoed by hem ae no abe o be measued [1]. Addiionay, he wo esing echnoogies of mecuy oosimey ae exensive, imeconsuming and coe-conaminaing. Thee is no a sime effecive mehod o descibe he asec aio. Foecas of he asec aio equies he choice of (1) a sime mehod of measuemen, () an effecive mode fo conveing he measuemen o he aio. Poes accoun fo oe voume and eesen caaciy. Thoas cono emeabiiy [,16]. Poosiy and emeabiiy esecivey efec oe scae and hoa scae, and hee exis ininsic funcions beween hem. In comaison o diecy measuing he asec aio wih mecuy oosimey, oosiy and emeabiiy, as maco hysica oey, can be esed easiy. Besides, eoeum geoogiss ae accusomed o chaaceizing esevoi ocks wih oosiy and emeabiiy insead of micoscoic oey aamees. So he uose of his ae is ha he mahemaica eaionshi beween asec aio and he maco hysica oey woud be esabished wih an absac oe-hoa mode o descibe he asec aio. Necking Thoa: Comacion is vey weak and cemen is few. The hoa is he educed a of he oe, and boh ae difficu o be disinguished. Rock has gea oosiy and huge emeabiiy. The asec aio is cose o one. Puncua Thoa: The gains ae oin-conac due o comacion. Thoas ae consiced enomousy hough he bodies of oes eained ae si age. The ock has high oosiy, ow emeabiiy and age asec aio. (Cuved) Laminaed Thoa: When comac effec is songe and essue souion makes cysas egow, he oes fomed by he egowh sides become sma and kee eaheda o oyheda shae. The hoas connecing oes ae inecysaine ceaances which ae aminaed o cuved aminaed due o he gain shae. The oening degee of aminaed hoas is exemey naow and aoximae o 1 μm. Laminaed hoa sandsones have exa-ow emeabiiy, modeae o ow oosiy and age asec aio. The conac aen of gains conains ine conac, concave-convex conac. Tube-bunde Thoa: When he ock has enough maix and cemen, he imay ineganua oes may be comeey cogged u. A age amoun of micooes, as many caiay ubes, ae unifomy disibued in he maix and cemen The micooes whose sizes ae usuay owe han μm ae no ony oes bu aso connecing channes wih suue conac and basa cemen. Poosiy is vey ow and emeabiiy is smae han μm. Because he oe is hoa in isef, asec aio is PORES AND THROATS IN ULTRA- LOW PERMEABILITY SANDSTONES 1.1 Scaes of Poosiy Sysem in Ua-Low Pemeabiiy Sandsones Measuemen esus of ae-conoed mecuy oosimey in he ieaues ae aied in his ae, amouning o foy-fou ua-ow emeabiiy ocks of vaious geoogic ages and fom vaious Chinese oifieds [17-1]. Coes dehs ange fom 00 o 3000 m. Pemeabiiy coves μm, and oosiy is 9.%-0.1%. The aveage oe adius ange is fom 3.7 μm o μm, and he mean hoa adius ange is fom 0.31 μm o.81 μm. These daa have ovided fuhe evidence ha uaow emeabiiy caused by fiece diageneses owefuy deceases hoa size wih sma oe size vaiaion fo sandock esevoi, which eads o highe asec aio. Asec aio exen of he comac coes is fom 7. o Poosiy Sysem Feaue of Ua-Low Pemeabiiy Sandsones Poosiy sysem feaue of sandsones is mainy subjec o conac ye and cemenaion ye of he gain. Thee ae fou common hoa yes as foows [] : a. Necking Thoa b. Puncua Thoa c. Laminaed Thoa d. Cuved Laminaed Thoa e. Tube-Bunde Thoa 1 Thoa Figue 1 Thoa Tye [] Evideny uncua hoa ock, aminaed hoa ock and ube-bunde hoa ock a have bad emeabiiy, and he hee have vas diffeence in he soage caaciy. The ua-ow emeabe sandsones in secion.1 have oosiyemeabiiy chaaceisic of aminaed hoa ocks. The oes of ocks may be quaiaive descibed by means of obseving he hin secion, bu he obabiiy of he ane of secion ineceing a hoa is amos ni []. The oe sucue of a sandsone same (1-3 μm, 11.8%) is anayzed by SEM. Poes ae undedeveoed, and facia oosiy is sma (Figue ). I coud be secuaed ha he oes ae conneced by ong naow aminaed hoas in he ua-ow emeabe sand ocks. Poe Coyigh Canadian Reseach & Deveomen Cene of Sciences and Cuues 8

3 WEI Haoguang; MA Kun; YUE Xiang an; WANG Xinxin (01). Advances in Peoeum Exoaion and Deveomen, 7(1), 7-1 Comac sandsones wih amea hoas have oo oe ineconnecion and vey age asec aio. Figue SEM Image of he Sandsone Same (1-3 μm, 11.8%) 1.3 Hyoheica Rock Mode Successfuy buiding he anayica fomuas beween mico sucue and maco oey cuciay ies in choosing a easonabe hyoheica ock mode, which no ony simuaes vaidy he oosiy sysem feaue of ua-ow emeabiiy ocks bu aso is abe o be used in anayic comuaion. The shae of oosiy sysem is vey comex. To eseach he hysica oey of esevoi ocks, sevea kinds of hyoheica ock mode have been esabished. Exessions of oosiy, emeabiiy coud be deived on he basis of hese modes [3,], such as: newok mode, uncaed cone mode, caiay bunde mode, comound caiay bunde mode and so on. The fuid seeage chaaceisics in oous media ae simuaed by comue echnoogy and wih newok mode which has been geay deveoed since 196 []. Comaed o numeica simuaion, aicaion of anayic cacuaion mehod is much fewe. Based on he emaining hee, soving anayic equaions abou he ock oey is feasibe. Tuncaed cone mode is vey anaogous o he necking hoa and uncua hoa. Caiay bunde mode ossesses sime comosiion. The mode is vey anaogous o he necking hoa and ube-bunde hoa because asec aio is 1. Comound caiay bunde mode is comised of unequa size caiaies in seies. The mode is used in his ae because he oosiy sysem ha oes ae conneced by he naow ong hoas in he comac ock is abe o be simuaed advanageousy, even hough he ea oe sace diffes fom he ube.. THEORETICAL ANALYSIS The main facos ae aveage oe size and aveage hoa size which ae diecy bound u o asec aio duing he heoeica anaysis. Many gous of ae-conoed mecuy oosimey esus ae used o vaidae he equaions deived in his ae..1 Reaion Beween Poosiy and Poe Radius In he comound caiay bunde mode, a oe is joined by equa-engh hoas, which consiss of a nonobjecive oe-hoa mode. Then he voume V in he singe oehoa mode is: ( ) V = π + (1) Hee, is coodinaion numbe, P is oe adius, is hoa adius, P is asec aio, P is oe engh, and is hoa engh. The aio of oe engh o hoa engh is P. Laminaed hoa is absaced as a sime caiay ube, and voume of he hyoheica hoa is equivaen o ha of ea hoa. Then hoa engh in he mode is much onge han is ea vaue. Lengh aio migh be ess han one, which wi be demonsaed deaiedy in secion 3.. Then, he oosiy of hyoheica ock is given by: naπ φ = ( ) + = A( + ) ( + 1) π n + In which A is coss aea, n is aea densiy of oehoa. Fo exame, o have a oosiy of 0%, he densiy (n) of oes wih 0 micons in adius has o be abou of 6 miion oes e squae mee. Coodinaion numbe of comac sandsones is sma. Equaion indicaes ha oe adius, hoa adius, aea densiy and he engh aio ae eaed o he oosiy of ua-ow emeabe sandsones. To sudy he asec aio, his ae ays cose aenion o he adii of oe and hoa. I can be found ha age scae oes ovide edominany soage sace (Figue 3). The mino hoas have ie voume in igh ocks, which means ha hee is ie eaiviy beween he hoa dimension and he oosiy (Figue ). Poosiy(%) () Poe Radius(μm) Figue 3 Poosiy Vesus Poe Radius 9 Coyigh Canadian Reseach & Deveomen Cene of Sciences and Cuues

4 The Reaionshi of Ua-Low Pemeabiiy Sandsone Asec Raio Wih Poosiy, Pemeabiiy Poosiy(%) 0 1 odes of magniude diffeence o ha of oes in igh oous media. The em P is negigibe comaed o he em P. Theefoe, emeabiiy of ua-ow emeabe sandsone is unconcened wih he oe adius, and he facos ha decide he eneaion of fuids ae hoa ais incuding size, engh, aea densiy, coodinae numbe and ouosiy whee he fow fied chaaceisic size is cucia. Facos eaed o asec aio ae invesigaed. Figues and 6 aso iusae ha hoa scae ahe han oe scae dominaes he fuid fow abiiy in he comac oous media Thoa adius(μm) Figue Poosiy Vesus Thoa Radius. Reaion Beween Pemeabiiy and Thoa Radius Now ay he Poiseuie aw o seek he quaniy of fow (q) in a oe-hoa mode: Pemeabiiy( -3 μm ) 1 π π q = = (3) 8µ 8µ In which, ΔP, ΔP and ΔPsymboize aiece he essue diffeences in oe, hoa and mode. Viscosiy is μ.the essue eaion is: + = () Subsiuing Equaion ino Equaion 3 yieds: π q = () 8µ ( + ) The fow of hyoheica ock Q is obained: π Q = naq = na (6) 8µ ( + ) Whie Dacy s aw fuid fow in a oous media is: KA Q = (7) µ ( + ) Equaing Equaions 6 and 7, and eaanging yieds he emeabiiy fomua: ( + 1) ( + ) πn K = (8) 8τ Whee τ is defined as ouosiy faco. Daa fom ieaues demonsae adii of hoas ae wo o hee Poe Radius(μm) Figue Pemeabiiy Vesus Poe Radius Pemeabiiy( -3 μm ) Thoa adius(μm) Figue 6 Pemeabiiy Vesus Thoa Radius.3 The Reaionshi Beween Asec Raio and Poosiy, Pemeabiiy fo Ua-Low Pemeabe Sandsones Lessening he scaes of oe and hoa, comacion and cemenaion geneay diminish esevoi quaiy. Wih a combined anaysis of Equaions and 8, eiminaion of he iem yieds: Coyigh Canadian Reseach & Deveomen Cene of Sciences and Cuues

5 WEI Haoguang; MA Kun; YUE Xiang an; WANG Xinxin (01). Advances in Peoeum Exoaion and Deveomen, 7(1), 7-1 ( + 1) φ K = 8π nτ ( + ) Reaanging Equaion 9 yieds: ( ) 3 + ( + ) (9) 3 1 φ = () n K 8 πτ The asec aio of ua-ow emeabiiy sandsone + is so age ha he second iem is negigibe comaed o he fis iem ( + ). Exacion of oo gives: φ /K ( + 1) 1. φ + = (11) nπτ K Exacing Equaion 11 and eaanging yieds: φ K = B + C (1) Asec aio Figue 7 Asec Raio Vesus Pemeabiiy, Poosiy Whee nπτ B = ( + ) 1. 1, nπτ C = ( + ) 1. 1 Equaion 1 manifess ha asec aio of ua-ow emeabe oous media is a funcion of oosiy, emeabiiy. The aamees of B and C ae consans associaed wih ock sucue on saisica aveages, and hey can be deemined by he exeimena fiing. In his aice, foy-fou gous of seed-conoed mecuy oosimey daa ae fied (see he ed cuve in Figue 7) and he fied vaues of B and C ae esecivey 0.000, Then he asec aio of ua-ow emeabiiy is abe o be descibed wih he foowing equaion: φ = (13) 0. K Equaion 13 is jus used o foecas he asec aio fo he sandsone whose emeabiiy coves μm, because measuemen esus of ae-conoed mecuy oosimey used in his ae he emeabiiy ies in he exen. The hoas of mid-high emeabiiy ocks ae big so ha sma asec aio makes iem + is no negigibe comaed o iem ( ) + in Equaion 11. The wo asec aios of mid-emeabe ocks do no accod wih Equaion 1. Now B divides by C o anayze he engh aio P. B = (1) C Coodinaion numbe of comac sandsones is sma, so he engh aio of oe o hoa is much ess han one. Thee ae wo yica easons accouning fo he P vaue. The hoas in he comac sandsones ae vey ong o connec he oes which ae ess han hose in conveniona ocks. Then he hyoheica oe-hoa mode makes hoa onge, ahough he mode descibes ecisey he hoa adius. The ea hoa shae is aminaed ahe han ubua, which means ha he engh of ubua hoa is enghened o kee he hoa voume invaian. Howeve, he P vaue has nohing o do wih he asec aio, which does no infuence he deived esu in his ae. CONCLUSIONS a. Ua-ow emeabiiy caused by fiece diageneses deceases hoa size much moe han oe-body size, which eads o highe asec aio and modeae o ow oosiy. Anaysis on he comac sand-ock by SEM indicaes ha oes undedeveo wih sma facia oosiy and he oes jus can be conneced by ong naow hoas. b. Comound caiay bunde mode advanageousy simuaes he hoa feaue of comac ock, even hough he ea oe sace diffes fom he ube. The anayica exessions of oosiy and emeabiiy abou majo oe sucue aamees ae esabished. The adii of oe, hoa esecivey cono oosiy and emeabiiy of igh ock in ems of he exessions. Afe souion, he eaion beween asec aio and oosiy, emeabiiy is obained. So he asec aio is abe o be edeemined wih he eaion. 11 Coyigh Canadian Reseach & Deveomen Cene of Sciences and Cuues

6 The Reaionshi of Ua-Low Pemeabiiy Sandsone Asec Raio Wih Poosiy, Pemeabiiy REFERENCES [1] Duien, F. A. L. (1979). Poous media-fuid anso and oe sucue. San Diego, Caifonia: Academic Pess. [] Edwad, L. E., David, S. B., Robe, E., e a. (1988). Reaions beween oes, hoas and emeabiiy: A eogahic/hysica anaysis of some cabonae gainsones and acksones. Cabonaes and Evaoies, 3(1), [3] Yang, Z. M., Zhang, Y. Z., Hao, M. Q., e a. (006). Comehensive evauaion of esevoi in ow-emeabiiy oifieds. Aca Peoiei Sinica, 7(), [] Chazis, I., Moow, N. R., & Lim, H. T. (1983). Magniude and deaied sucue of esidua oi sauaion, SPE J, 3(), [] Li, Y., & Wadaw, N.C. (1986). The infuence of weabiiy and ciica oe-hoa size aio on sna-off. Jouna of Cooid and Ineface Science, 9(), [6] Mogensen, K., & Senby, E. H. (1998). A dynamic wohase oe-scae mode of imbibiion. Tanso in Poous Media, 3(3), [7] Ceei, A., Duand, C., & Bosse, E. (00). Poe micogeomey anaysis in ow-esisiviy sandsone esevois. Jouna of Peoeum Science and Engineeing, 3(3), 0-3. [8] Li, Z. Q., Hou, J., Cao, X. L., e a. (00). Micoscoic simuaion fo infuence of micoscoic esevoi aamees on emaining oi disibuion. Aca Peoiei Sinica, 6(6), [9] Mahmud, W. M., & Nguyen, V. H. (006). Effecs of snaoff in imbibiion in oous media wih diffeen saia coeaions. Tanso in Poous Media, 6(3), [] Gao, H. M., Jiang, H. Q., & Chen, M. F. (007). Simuaion sudy on he effec of he micoscoic aamees of esevoi oe sucue on oi-wae eaive emeabiiy. Jouna of Xi an Shivou Univesiy: Naue Science Ediion, (), 6-9. [11] León y León, C. A. (1998). New esecives in mecuy oosimey. Adcances in Cooid and Ineface Science, 76, [1] Aguiea, R. (00). Incooaing caiay essue, oe hoa aeue adii, heigh above fee-wae abe, and winand 3 vaues on Picke os. AAPG Buein, 86(), [13] Teige, G. M. G., Hemanud, C., Thomas, W. L. H., e a. (00). Caiay esisance and aing of hydocabons: A aboaoy exeimen. Peoeum Geoscience, 11(), [1] Yuan, H. H., & Swanson, B. F. (1989). Resoving oesace saisics and caiay by ae conoed oosimey. Sociey of Peoeum Enginees Fomaion Evauaion, (1), 17-. [1] Wang, R. F., Shen, P. P., Song, Z. Q., e a. (009). Chaaceisics of mico-oe hoa in ua-ow emeabiiy sandsone esevoi. Aca Peoiei Sinica, 30(), 60-63, 69. [16] Neson, P. H. (009). Poe-hoa sizes in sandsones, igh sandsones, and shaes. AAPG Buein, 93(3), [17] Wang, R. F. (007). Reseach on micocosmic chaaceisics and quaiy evouion in ow emeabiiy sandsone esevoi (Docoa disseaion). Nohwes Univesiy, China. [18] Xie, W. (008). A sudy on mico-oe sucue and infiaing mechanism of Chang-8 esevoi in Qingyang aea Xifeng oified (Docoa disseaion). Nohwes Univesiy, China. [19] Mao, C. L. (006). Evauaion on chaaceisics of deaic fon sand bodies of Gao-Tai-Zi Resevoi in Changing deession, souhen Songiao basin (Docoa disseaion). China Univesiy of Geosciences, China. [0] Gao, H. (009). Reseach on mico-oe sucue and mico-fow mechanism of ua-ow emeabiiy sandsone esevoi (Docoa disseaion). Nohwes Univesiy, China. [1] Guo, Q. (008). A sudy on mico-oe sucue and infiaing mechanism in Niuquanhu aea of Sananghu oified as an exame o Qigu gou and Touunhe gou (Docoa disseaion). Nohwes Univesiy, China. [] Luo, Z. T., & Wang, Y. C. (1986). Poe sucue of hydocabon esevoi. Beijing: Science Pess. [3] Fa, I. (196). The newok mode of oous media I. Caiay essue chaaceisics Peoeum Tansacions. AIME, 07(7), [] Yang, Y. L., & Ain, A. C. (1998). Infuence of ihoogy and comacion on he oe size disibuion and modeed emeabiiy of some mudsones fom he Nowegian magin. Maine and Peoeum Geoogy, 1(), [] Chen, S., & Dooen, G. D. (1998). Laice Bozmann mehod fo fuid fows. Annua Review of Fuid Mechanics, 30(1), Coyigh Canadian Reseach & Deveomen Cene of Sciences and Cuues 1