Kev txiav txim siab ntawm Subsurface 'CT': Pauv Log

Yuav ua li cas geologists "pom" roj thiab roj reservoirs ntau txhiab meters hauv qab lub ntiaj teb nto? Lawv thawj "magic eye" yog zoo loging tshuab. Yog hais tias qhov drilling zoo li muab lub ntiaj teb txhaj tshuaj, ces kev txiav yog zoo li tso cov koob ntawm cov sensors rau hauv "kab qhov" los ua ib qho "CT scan" ntawm kev tsim.

Txawm li cas los xij, cov khoom siv raw-cov yeeb yuj, undulating nkhaus- tsis yog cov lus teb kawg. Lawv tsuas yog cov ntaub ntawv teb lub cev, zoo li cov duab dub - thiab - cov duab dawb los ntawm lub tsev kho mob CT scanner, uas tsis muaj nuj nqis yam tsis muaj kws kho mob kuaj mob. Txhais cov nkhaus no rau hauv cov lus geological intuitive (qhia cov xuab zeb, ntsuas qhov porosity, txiav txim siab cov ntsiab lus dej) yuav tsum muaj cov kauj ruam tseem ceeb:log txhais lus. Qhov no yog txheej txheem "decoding" ua ke nrog physics, geology, thiab computer science.

Cov kab lus no tau taug kev los ntawm "tus qauv sib dhos kab" ntawm kev txhais cov lus sib dhos, qhia seb cov ntaub ntawv subsurface tau txiav txim siab li cas los ntawm kauj ruam.

Qhov no yog hais txog "pob yooj yim" ntawm cov tub ntxhais nkhaus kev sib txuas ua haujlwm ntawm yuav luag txhua qhov dej. Nws yog tus nqi- zoo thiab siv tau dav, tsim lub hauv paus ntawm txhua qhov kev txhais lus.

• Gamma Ray (GR):Ntsuas tej yam ntuj tso radioactivity. Shales muaj GR siab; huv sandstones / carbonates muaj tsawg GR. Nws yog cov cuab yeej tseem ceeb rau kev paub qhov txawv ntawm shale los ntawm cov pob zeb muaj peev xwm reservoir.
• Kev Muaj Peev Xwm Muaj Peev Xwm (SP):Ntsuas qhov hluav taws xob muaj peev xwm sib txawv. Nyob rau hauv permeable sandstones, nws qhia meej deflection (anomaly), pab txheeb xyuas permeable zones thiab kwv yees tsim dej salinity.
• Kev tiv thaiv:Covcore nkhaus. Pob zeb moj khaum tsis yog -kev coj; conductivity los ntawm saline dej nyob rau hauv pores. Pob zeb nrog siab - dej qab ntsev muaj qhov tsis muaj zog heev; pob zeb uas muaj roj / roj (insulators) qhiasiab heev resistivity. Nws yog tus yuam sij rau kev paub qhov txawv ntawm thaj chaw hydrocarbon los ntawm thaj chaw dej.

• Qhov "Porosity Trio":Peb cav ua ke los xam porosity (qhov chaw tsis muaj pob zeb).

  1.Sonic Transit Sijhawm (AC / DT):Ntsuas lub suab nthwv dej lub sijhawm mus ncig. Lub sij hawm mus qeeb qeeb (ntau dua lub sijhawm thauj mus los) feem ntau qhia tias muaj porosity ntau dua.

  2.Density (DEN/RHOB):Ntsuas ntau qhov ntom ntom. Qhov ntom ntom qis tuaj yeem qhia tau tias qhov porosity siab dua lossis muaj lub teeb hydrocarbons.

  3.Neutron (CNL/NPHI):Ntsuas qhov "hydrogen index," siab heev rau cov kua (dej thiab roj) hauv qhov hws, yog li qhia qhov porosity.

Cov txheej txheem kev txhais lus nruj ua raws cov kauj ruam sib txuas xws li kab sib dhos. Ib qho kev saib xyuas tuaj yeem ua rau muaj kev sib txawv hauv cov lus xaus kawg.

Kauj Ruam 1: Kev Npaj Cov Ntaub Ntawv & Kev Tswj Xyuas Zoo (QC)

Qhov no yog theem "foundation-laying". Yog tias cov ntaub ntawv nyoos tsis muaj qhov tsis zoo, cov kev txhais lus tom ntej yuav tsis muaj qab hau ("Cov khib nyiab hauv, khib nyiab tawm").

• Data Loading & Verification:Xyuas kom tag nrho cov nkhaus tau ntim nrog cov npe raug, units, thiab cov ntaub ntawv tob.
• Qhov sib sib zog nqus:Cov cuab yeej sib txawv khiav hauv kev sib cais tuaj yeem muaj qhov sib txawv tob. Aligning tag nrho cov nkhaus mus rau qhov kev siv qhov tob sib xws yog qhov tseem ceeb.
• Kev kho ib puag ncig:Cov kev ntsuas raw tau cuam tshuam los ntawm qhov loj ntawm qhov borehole, av nkos invasion, kub, thiab siab. Software lossis kab kos yog siv los kho cov teebmeem no thiab rov qab tsim cov txiaj ntsig muaj tseeb.
• Kev kuaj xyuas zoo:Tshem tawm "spikes" (cov ntaub ntawv yuam kev los ntawm cov cuab yeej malfunctions) thiab chij ncua sij hawm nrog cov ntaub ntawv distortion vim borehole vau.

Kauj Ruam 2: Kev txhais lus zoo

Nrog kev kho qhov nkhaus, tus neeg txhais lus pib pib "kev kuaj mob" raws li cov qauv hauv geological thiab kev paub txog cov qauv.

• Lithology Identification:Siv GR/SP ua ntej cais thaj chaw sandstone (tsawg GR, SP anomaly) los ntawm shale aav (siab GR, tiaj tus SP). Hla-ploj (piv txwv li, neutron- ntom) yog cov cuab yeej muaj zog rau kev txheeb xyuas cov lithologies nyuaj.
• Reservoir Identification:Saib rau cov yam ntxwv kos npe zoo li qis GR (tsawg shale) ua ke nrog porosity qhia los ntawm trio thiab siab resistivity (muaj peev xwm hydrocarbon).
• Kev txheeb xyuas kua:

  1.High Resistivityyog thawj qhov taw qhia ntawm hydrocarbons.

  2.Qhov "Gas Effect":Gas muaj tsawg ntom ntom thiab hydrogen index. Hauv thaj chaw roj av, covdensity log nyeem tsawg dhau(porosity siab porosity), thiab covneutron log nyeem tsawg dhau(porosity tsawg tsawg), tsim ib qho classic "crossover" lossis "sib cais" qauv - qhov taw qhia roj tseem ceeb.

• Stratigraphic Zonation:Faib qhov dej mus rau hauv "txheej txheem" ​​raws li kev hloov pauv ntawm tus cwj pwm nkhaus, npaj rau kev txheeb xyuas kom muaj nuj nqis.

Kauj Ruam 3: Kev suav lej

Qhov no yog cov txheej txheem tseem ceeb, tig cov hunches zoo ("qhov no zoo li roj") rau hauv cov lej ntau ("10-meter cheeb tsam nrog 15% porosity thiab 70% roj saturation").

• Muab xam Shale Volume (Vsh):Shale nyob rau hauv reservoir pob zeb tuaj yeem txhaws qhov pores thiab cuam tshuam rau kev tiv thaiv. Siv GR (los yog lwm txoj kev), qhov feem pua ​​​​ntawm shale ntim yog xam. Qhov tseeb Vsh yog qhov tseem ceeb rau kev suav tom ntej.
• Calculate Porosity (φ):Qhov no txiav txim siab npaum li cas lub pob zeb tuav tau.

  1.Txoj kev:Siv sonic, ceev, lossis neutron cav ib leeg zuj zus, txhua tus muaj cov qauv tshwj xeeb (xws li lub sijhawm Wyllie - nruab nrab qhov sib npaug rau sonic). Txoj kev muaj zog tshaj plaws ua kecov ntaub ntawv ceev thiab neutronhauv cross-plots. Qhov "density-neutron cross-plot" tuaj yeem daws tau ib txhij rau porosity thiab lithology, kho kom zoo rau shale thiab roj los ua kom muaj txiaj ntsig zoo tshaj plawstag nrho porosity.

  2.Effective Porosity (φe):Tag nrho porosity rho tawm qhov ntim ntawm dej khi rau av nplaum. Qhov no sawv cev rau qhov sib txuas qhov pore qhov chaw uas cov kua dej tuaj yeem ntws tau thiab yog qhov tseem ceeb rau kev tsim khoom.

• Calculate Water Saturation (Sw):Qhov no teb cov lus nug tseem ceeb tshaj plaws: ntau npaum li cas ntawm qhov pore qhov chaw ntim nrog dej piv rau hydrocarbons?

  1.Tus Qauv Txheej Txheem: Archie's Equation- Lub hauv paus pob zeb kom huv si (shale{0}}dawb) formations. Nws hais txog:
  Sw^n=(a * Rw) / (Rt * φ^m)
  (Qhov twg a, m, n yog lithology-nyob ntawm qhov kev sim ntawm cov tub ntxhais kawm)

  2. Logic:Peb muaj qhov tseeb tsim resistivity (Rt) los ntawm cov cav sib sib zog nqus. Peb tau suav porosity (φ). Peb kwv yees tsim cov dej tiv thaiv (Rw) los ntawm SP lossis cov qauv dej. Txuas cov no tso cai rau kev daws rau Sw.

  3.Hydrocarbon Saturation (Sh):Sh=1 - Sw.

  4. Shaly Sand Kho:Hauv kev tsim nrog shale, Archie qhov sib npaug overestimates Sw vim shale ua hluav taws xob. Cov qauv ntau dua (piv txwv li, Simandoux, Indonesia) yog qhov yuav tsum tau ua.

Kauj Ruam 4: Cov txiaj ntsig muab tso ua ke & Kev Ntsuas Kev Ntsuas

Qhov kawg "daim ntawv qhia" theem.

• Tsim Composite Log Plot:Tag nrho cov qub nkhaus thiab suav tsis tau (Vsh, porosity, Sw, lithology profile) yog npaj ua ke. Qhov no yog qhov tsim qhov kawg "diagnostic report."
• Thov "Cutoffs":Txhawm rau txheeb xyuas thaj chaw muaj txiaj ntsig zoo ("thaj chaw them nyiaj"), cov qauv yam tsawg kawg yog siv raws li kev paub hauv cheeb tsam. Piv txwv li:

  1.Shale Volume (Vsh) <40%

  2.Effective Porosity (φe) > 8%

  3. Dej Saturation (Sw) <60%

• Txheeb xyuas cov dej sib cuag:Kom meej meej kos cov cheeb tsam roj, thaj chaw roj av, thaj chaw dej, thiab thaj chaw hloov pauv ntawm thaj chaw.

• Sau Cov Ntsiab Lus Txhais Lus:Qhov kawg khoom xa tuaj qhia txog cov reservoirs ntsib, lawv thickness, zoo (porosity), thiab hydrocarbon cov ntsiab lus (saturation). Qhov no tsim lub hauv paus rau geological qauv, kev kwv yees cia, thiab kev txiav txim siab kev loj hlob (xws li, qhov twg yuav perforate).

Kev txhais lus log yog txheej txheem kev txiav txim siab nruj uas hloov pauv cov kev ntsuas lub cev mus rau hauv qhov kev xav tau geological. Nws pib nrog QC nruj me ntsis, tsom lub hom phiaj los ntawm kev soj ntsuam zoo, ntsuas cov khoom siv lub cev thiab kev ua lej, thiab ua tiav cov kev ntsuam xyuas uas qhia txog kev drilling thiab kev tsim khoom. Qhov kev ua haujlwm no xav tau tsis yog cov kev paub theoretical nkaus xwb tab sis kuj tseem siv tau los paub txog qhov nkhaus twg yog qhov kev ntseeg siab tshaj plaws thiab tus qauv twg haum zoo tshaj plaws hauv cov ntsiab lus geological. Tus neeg txhais lus cav yog ib tus kws kos duab kos duab kos duab ntawm qhov chaw zais thiab tus navigator coj txoj hauv kev ntawm kev tshawb nrhiav.Yog xav paub ntxiv, thov tsis txhob yig tiv tauj pab pawg Vigor kom paub ntau ntxiv txog cov khoom lag luam.