Mhedzisiro yeKudzvanywa kwePore paZviratidzo zveGeophysical
Pendauluan
Mu geology ne geophysics, kumanikidzwa kwepore ndeimwe yezvinhu zvakakosha zvinodzora maitiro ematombo ari pasi pevhu. Kumanikidzwa kwepore kunotsanangurwa sekumanikidzwa kwemvura (mvura, oiri, gasi, kana musanganiswa weizvi) inozadza nzvimbo dzepore dzedombo. Kumanikidzwa kwepore kunogona kusiyana zvichienderana nekudzika, lithology, mamiriro e tectonic, uye nhoroondo yekuisa uye yekubatanidza. Muzviitiko zvakawanda, kumanikidzwa kwepore hakutevedzere maitiro e hydrostatic, asi kunogona kuva kwakakwira (overpressure) kana kuderera (underpressure). Kuchinja uku hakungokanganisi chete kuchengetedzeka uye dhizaini yekuboora asiwo kunokanganisa ma parameter e geophysical akadai seismic wave velocity, density, resistivity, acoustic log response, uye seismic attributes zvinoshandiswa pakududzira reservoir. Chinyorwa chino chinokurukura kuti kumanikidzwa kwepore kunokanganisa sei ma parameter e geophysical, mashandiro ayo, uye zvazvinoreva pakutsvaga uye kuratidza pasi pevhu.
Pfungwa Dzekutanga: Kumanikidzwa Kwepore, Kushushikana Kunobudirira, uye Rombo Rakaumbwa
Hukama hukuru hunobatanidza kumanikidzwa kwepore uye hunhu hwedombo hunotsanangurwa nepfungwa yekushushikana kunoshanda. Muchidimbu, kushushikana kunoshanda ndiko kushushikana kunotakurwa nedombo, kwete nemvura yepore. Mukunyora kwaTerzaghi, kushushikana kunoshanda (σ') kunogona kunyorwa seizvi:
σ' = σ – Pp ,
apo σ iri kushushikana kwese (overburden stress) uye Pp iri kumanikidzwa kwepore. Sezvo kumanikidzwa kwepore kuchiwedzera, kushushikana kunoshanda kunoderera. Kudzikira uku kwekumanikidzwa kunoshanda kunoita kuti dombo rive "nyoro" uye rive nyore kuchinja. Kuchinja uku kwekuomarara kunokanganisa zvakananga kumhanya kwemafungu epasi (Vp naVs), elastic modulus, uye dzimwe mhinduro dze geophysical dzine chekuita nekuoma uye kumanikidzwa kwemedium.
Mhedzisiro yeKudzvanywa kweMaburi paKumhanya kweMafungu eSeismic
1. Kumhanya kweP Wave (Vp)
Mafungu eP anonyanya kunzwa shanduko muhuwandu hwema "bulk modulus" uye huwandu hwematombo. Sezvo kumanikidzwa kwema "pore" kuchiwedzera, kushushikana kunoshanda kunoderera, zvichiita kuti kusangana pakati pe "granular" kusashande zvakanaka uye kunoita kuti dombo rive nyore kudzvanywa. Nekuda kweizvozvo, Vp inowanzo kudzikira. Mhedzisiro iyi inonyanya kuoneka mumatombo e "shale" ne "sandstone sedimentary", uko ma "pore" achiri kuita basa guru mu "rock mechanics".
Kana paine kumanikidzwa kwakanyanya, kuderera kweVp kunowanzo shandiswa sechiratidzo chisina kunanga. Munzvimbo zhinji dzine sedimentary basin, nzvimbo dzine kumanikidzwa kwakanyanya dzinoratidza kumhanya kwakaderera zvichienzaniswa nemaitiro akajairika ekumanikidzana. Nokudaro, kuongorora kumhanya uye magwaro enzwi zvishandiso zvakakosha pakufanotaura kumanikidzwa kwepore usati waboora.
2. Kumhanya kweS Wave (Vs)
Mafungu eS anowirirana zvakanyanya ne shear modulus, iyo inonyanya kutsanangurwa ne rock framework, kwete fluid. Zvisinei, shanduko mukumanikidzwa kunoshanda ichiri kukanganisa kuomarara kwe framework, saka Vs inogonawo kudzikira sezvo kumanikidzwa kwe pore kuchiwedzera. Kunyange zvazvo Vs kazhinji isinganyanyi kukanganiswa nekuchinja kwe fluid pane Vp, mumatombo asina simba kana ane maburi akawanda, mhedzisiro yekuderedza kushushikana kunoshanda inogona kuve yakakosha. Chiyero cheVp/Vs chinowanzo shandiswa kuongorora shanduko dze elastic dzinogona kunge dzakabatana nekumanikidzwa kwe pore uye fluid saturation.
3. Hunhu hweKutenderera kweNyika uye Kukura kweMamiriro ekunze
Kumanikidzwa kwepore kunokanganisa acoustic impedance (AI = ρVp). Kana Vp ikadzikira uye density ikasawedzera zvakanyanya, acoustic impedance ichaderera. Kusiyana uku kweimpedance kunokanganisa amplitude ye seismic reflections. Mune zvimwe zviitiko, overpressure inogona kugadzira ma reflectors akasimba kana mapatani chaiwo e seismic, kunyangwe dudziro inofanira kungwarira sezvo mhedzisiro ye lithological uye hydrocarbon fluids zvinogonawo kugadzira mhinduro dzakafanana.
Mhedzisiro paKuwanda uye Kushanda kwePorosity
Kuwanda kwematombo pakadzika kunowanzowedzera nekuda kwekuoma, nepo kuoma kunoderera. Zvisinei, kana kumanikidzwa kwepore kwakakwira, kuoma kunodziviswa: mapore anoramba akakura kupfuura anofanirwa kunge ari pakadzika ikoko. Nekuda kweizvozvo, kuoma kunogona kuva kwakakwira uye kuoma kwebulk kuderera pane zvakajairika. Chiitiko ichi chinowanzo kuwanikwa mushale yakamanikidzwa zvakanyanya nekuda kwekuoma (kusakwana kwekuoma). Kubva palog yehurema, nzvimbo dzekuoma dzinogona kuonekwa sehurema hwakaderera pane hunotarisirwa pakadzika kwakapihwa.
Mhedzisiro paKuramba uye Kufambisa
Kuramba kwematombo kunonyanya kukonzerwa nerudzi rwemvura yemumaburi, munyu, kubatana kwemumaburi, uye huwandu hwevhu. Kumanikidzwa kwemumaburi hakuchinji zvakananga kuramba kwemvura sekuchinja kwehuwandu hwehydrocarbon, asi kunogona kukanganisa kuramba kwemvura kuburikidza nenzira dzisina kunanga:
1. Kuchinja kwemaburi uye maburi madiki: Kudzvinyirirwa kwakanyanya kunoita kuti pave nemaburi akawanda kunogona kuwedzera huwandu hwemvura inofambisa mvura uye kuderedza resistivity.
2. Kuchinja kwekuzara kana kufamba kwemvura: Mune mamwe masisitimu epeturu, kumanikidzwa kwakawanda kwemapore kunobatanidzwa nekuunganidzwa kwegasi kana hydrocarbon, izvo zvinogona kuwedzera resistivity. Zvisinei, izvi hazvikonzerwi nekumanikidzwa kwemapore chete, asi nekuda kwekushanduka kwemvura.
3. Mhedzisiro yemakemikari ekupisa uye mvura: Nzvimbo dzine kumanikidzwa kwakanyanya dzimwe nguva dzinobatanidzwa nekupisa kwakanyanya uye shanduko mumunyu, izvo zvinogadzirisawo resistivity.
Nekuda kwezvinhu zvakawanda zvinopindirana, resistivity haiwanzo shandiswa sechiratidzo chikuru chekumanikidzwa kwepore pasina rutsigiro rwemamwe mashoko (sonic, density, uye drilling data).
Kupesvedzera kweAcoustic Log (Sonic Log) uye Kufanotaura kwePore Pressure
MaSonic logs anoyera nguva yekufamba kwemaacoustic waves (Δt). Sezvo Vp ichiderera, Δt inowedzera. Mutsananguro yekumanikidzwa kwepore, nzira yakajairika ndeyekuenzanisa Δt yakayerwa nemaitiro akajairwa ekumanikidzwa. Δt yakakura kupfuura maitiro akajairwa pakadzika kwakapihwa inowanzo tsanangurwa sekuratidza kumanikidzwa kwakanyanya, kunyanya mu shale. Nzira dzeEmpirical dzakadai senzira yaEaton dzinoshandisa kutsauka kwelog yesonic (kana resistivity) kubva pane maitiro akajairwa kuti dziongorore gradient yekumanikidzwa kwepore. Kunyange zvazvo nzira iyi ichishanda, kushandiswa kwayo kunoda kuenzaniswa nedata rekuyedza kuumbwa, uremu hwematope, kana kumanikidzwa kwakananga kudzivirira kusarura nekuda kwekuchinja kwe lithology.
Elastic Modulus uye Ukama Hwayo Nekumanikidzwa Kwepore
Maparamita egeomechanical akadai seYoung's modulus (E), bulk modulus (K), uye Poisson's ratio (ν) anochinjawo nekuchinja kwekumanikidzwa kwepore nekuti zvinoenderana nekumanikidzwa kunoshanda uye mamiriro ekubatana kwezviyo. Kazhinji, kuwedzera kwekumanikidzwa kwepore kunoderedza kuomarara kwedombo (kuderera kweE neK). Izvi zvakakosha muchirevo che:
– Kugadzikana kwegomba: kumanikidzwa kwakanyanya kunoderedza kushushikana kunoshanda kuitira kuti dombo riputsike kana kuti rive nyore nyore.
– Uinjiniya hwedhamu: Kugadzirwa kwemvura kunoderedza kumanikidzwa kwepore, kunowedzera kushushikana kunoshanda, uye kunogona kukonzera kusimba kwedhamu uye kudzikira kwenzvimbo. Shanduko idzi dzinoongororwa kuburikidza ne4D seismic (nguva-kupera).
Zvinoreva Kududzirwa Kwekudengenyeka Kwenyika uye Maitiro Edura Remvura
Kuchinja kwekumanikidzwa kwepore kunogona kukonzera kusagadzikana kwekudengenyeka kwenyika uko dzimwe nguva kunonzwisiswa zvisizvo sekuchinja kwe lithology kana hydrocarbons. Semuenzaniso, nzvimbo ine kumhanya kushoma inogona kufungidzirwa kuti ine pore yakawanda kana kuti ine gasi rakawanda, asi zvinogonawo kunge zvichikonzerwa nekumanikidzwa kwakanyanya. Saka, dudziro yakabatana yakanaka:
1. Kuenzanisa nedata retsime (huremu hwevhu, RFT/MDT, DST, log yesonic-density).
2. Kuongororwa kwemaitiro ekusimbaradza shale senzira yekutarisa.
3. Kuenzanisa physics yedombo (semuenzaniso Gassmann fluid substitution pamwe chete nekugadzirisa kushushikana kunoshanda) kuti uparadzanise mhedzisiro yemvura nekumanikidzwa.
4. Kubatanidzwa kwe geomechanics kuitira kuti shanduko dzinochinjika dzinzwisiswe muchimiro chekushushikana.
Mhedziso
Kumanikidzwa kwepore kune simba guru pamatanho e geophysical nekuti kunodzora kushushikana kunoshanda kunosarudza kuomarara kwedombo. Kuwedzera kwekumanikidzwa kwepore kunowanzo deredza Vp neVs, kunowedzera nguva yekufamba kwesonic log, kuchengetedza porosity yakakwira, uye kunoderedza huwandu hwakawanda hwezvinhu zvichienzaniswa nemaitiro akajairwa ekumanikidzana. Kuramba kuripo kunogonawo kukanganiswa nenzira isina kunanga kuburikidza nekuchinja kweporosity, salinity, kana fluid dynamics. Mukushandiswa kwezvinoshanda, kunzwisisa hukama huripo pakati pekumanikidzwa kwepore uye geophysical response kwakakosha pakufanotaura kwekumanikidzwa kusati kwacherwa, kududzira kwakarurama kwe seismic, uye kugadzirisa njodzi dze geomechanical uye kugadzirwa. Nzira yakabatana - kusanganisa seismic, well logs, uye rock physics models - ndiyo kiyi yekusiyanisa mhedzisiro yekumanikidzwa kwepore kubva ku lithology uye fluid effects, zvichikonzera kududzirwa kwakavimbika kwepasi pevhu.
