Qhov txawv thiab Cov Ntsiab Cai ntawmPAC (Polyanionic Cellulose)thiabCMC (Sodium Carboxymethyl Cellulose)hauvKev siv roj Drilling
I. Qhov txawv hauvMolecular Structure thiab Cov Ntsiab Cai
1. CMC (Sodium Carboxymethyl Cellulose): Raw khoom: paj rwb linters / ntoo cellulose, hloov los ntawm etherification nrog chloroacetic acid:
Degree ntawm kev hloov pauv (DS): Feem ntau 0.6–0.8, tsis sib npaug ntawm cov pab pawg hloov pauv.
Ob peb hydrophilic carboxymethyl pawg ntawm cov saw molecular, kev sib cais.
Tsuas yog nyob ntawm pawg carboxyl rau kev nqus dej thiab av nplaum adsorption; tsis muaj zog ntsev thiab calcium tiv thaiv moj khaum.
2. PAC (Polyanionic Cellulose): Ib qho khoom siv kho dua tshiab ntawm kev hloov pauv, homogeneous CMC, etherified siv cov txheej txheem tshwj xeeb:
DS Ntau dua lossis sib npaug rau 0.9, qee qhov siab - cov khoom kawg tuaj yeem ncav cuag 1.0–1.2.
Cov pab pawg anionic muaj ntau yam sib npaug ntawm cov saw cellulose ntev.
Muaj zog molecular saw rigidity, thicker hydration zaj duab xis, ho txhim kho tsis kam mus rau ionic shock.
Qhov tseem ceeb: PAC yog refined, siab homogeneous, heev hloov CMC; lawv tsis yog cov khoom sib txawv kiag li, tab sis cov txheej txheem ua tau zoo sib txawv heev.
II. Kev sib piv ntawmMechanisms of Action (Drilling Fluid Systems)
1. Mechanism kom txo qhov pom kev poob
Ob leeg ua haujlwm ntawm tib lub hauv paus ntsiab lus: Tom qab dissolving nyob rau hauv dej, cov polymer chains adsorb mus rau saum npoo ntawm bentonite, xyaum cuttings, thiab wellbore shale, bridging hais thiab compressing lawv los tsim ib tug ntom, nyias av nkos ncuav mog qab zib, tiv thaiv cov theem ntawm cov kua los ntawm kev nkag mus rau hauv lub tsim.
Qhov txawv yog nyob rau hauv stability:
CMC: Thaum ntsib cov calcium, magnesium, lossis sodium ions, pawg carboxyl tau yooj yim tiv thaiv los ntawm cov hlau ions, ua rau cov polymer kom ntsws, ua rau lub ncuav mog qab zib tuab thiab ua rau pom kev poob.
PAC: Nrog kev hloov pauv tsis sib xws, ntau qhov chaw anionic ib txhij adsorb hlau ions, ua rau nws tsis tshua muaj kev poob qis; lub ncuav mog qab zib tseem ntom ntom txawm nyob hauv siab - ntsev, siab -calcium ib puag ncig.
2. Viscosity Enhancement thiab Propellant Carrying Mechanism
Polymer hydration nthuav dav cov saw hlau molecular, ua kom cov viscosity thiab dynamic shear force ntawm cov kua theem, ncua kev xyaum txiav.
PAC-HV cov molecules muaj ntau dua extensibility, ua rau muaj viscosity deb tshaj qhov CMC zoo tib yam ntawm tib qhov ntau npaum; PAC-LV molecules undergo viscosity- tswj kev hloov kho, yuav luag tag nrho txo cov dej poob thiab txo qhov thickening.
Ordinary CMC nthuav tawm cov viscosity hloov pauv loj, nrog cov viscosity poob sai sai hauv brine, yooj yim ua rau cov xuab zeb nyob hauv lub sijhawm drilling nres.
3. Shale Inhibition thiab Collapse Prevention Mechanism: Polymers encapsulate av nplaum hais, tiv thaiv dej molecules los ntawm nkag mus rau shale crystal txheej thiab nthuav.
CMC muaj txheej nyias nyias, ua rau nws yooj yim rau detachment nyob rau hauv siab - ntsev ib puag ncig.
PAC muaj zog dua anionic adsorption, uas ua rau muaj zog txheej txheej thiab zoo inhibition ntawm shale hydration thiab exfoliation.
4. Kub thiab Biodegradation Resistance:
CMC molecules feem ntau muaj kev ruaj ntseg tsawg, nrog rau kev ua tau zoo txo qis dua 120 degree; lawv tau yooj yim decomposed thiab rendered ineffective los ntawm av nkos kab mob.
PAC muaj cov qauv molecular tsis tu ncua, tiv taus kub txog 140-160 degree; Nws tiv thaiv microbial yaig thiab tsis tshua muaj kev puas tsuaj hauv qhov dej tob thiab kev mus ntev.
III. Qhov txawvnyob rau hauv Qhov Tseeb Drilling Applications
1. PAC-LV (Low-Viscosity polyanionic cellulose)
Nta: Tsawg viscosity nce, tsom rau kev pom kev tswj; resistant rau saturated brine, calcium intrusion, thiab seawater.
Tsim nyog rau: Offshore drilling, siab- ntsev tsim, siab-cov av nkos hnyav, cov dej ua tiav ntawm cov dej hauv pas dej, thiab cov dej drilling uas yuav tsum tau muaj cov viscosity tsawg thiab ceev drilling.
Disadvantages: Tsis muaj zog viscosity nce; xav tau qhov sib ntxiv ntawm xanthan cov pos hniav thiab bentonite thaum cov av nkos tsis zoo.
2. PAC-HV (High-Viscosity polyanionic cellulose)
Nta: Cov viscosity siab, ua ke nrog kev txo qis, cov xuab zeb muaj zog - nqa peev xwm.
Haum rau: nruab nrab- qhov dej tob hauv ntug dej, qhov dej taw qhia, qhov dej ntiav ntiav thiab yooj yim collapsible, thiab dej- raws li cov dej drilling.
Tus nqi -effectiveness: Tsawg thickener ntxiv, yooj yim formulation.
3. Ordinary CMC (Industrial / Drilling Qib) CMC (Chemical Molecular Control)
Qhov zoo: Tus nqi pheej yig, txaus rau qhov dej ntiav ntiav
Disadvantages: Salinity poob qis heev nrog kev ua haujlwm siab; ceev siab - kub tsis ua hauj lwm; nquag mus rau fermentation, luv luv av nkos lub sij hawm; unstable av nkos ncuav mog qab zib zoo, nquag mus thickening, siab frictional kuj
Haum rau: qhov dej ntiav ntiav, ua liaj ua teb drilling, qis- tus nqi qis qhov dej tshawb nrhiav; feem ntau haum rau offshore, tob, thiab siab - qhov dej salinity
IV. Cov ntsiab lus yooj yim ntawm Kev Xaiv
Nyob ze ntug dej hiav txwv, txawv teb chaws tej yaam num, brine qhov dej, qhov tob tob, qhov dej taw qhia → PAC yog tsim nyog
Cov dej tsis zoo ntawm ntug dej hiav txwv, kev siv nyiaj tsawg → CMC tuaj yeem siv los txo cov nqi
Rau cov av nkos uas tsis tshua muaj viscosity thiab dej poob tswj → PAC-LV
Kom nce viscosity, nrog rau cov xuab zeb, thaum tswj dej poob → PAC-HV
