HEC rau Roj Drilling

Hydroxyethyl cellulose (HEC) yog dav siv nyob rau hauv ntau lub lag luam sector rau nws cov khoom zoo heev ntawm thickening, ncua kev kawm ntawv, dispersion thiab dej tuav. Tshwj xeeb tshaj yog nyob rau hauv cov roj teb, HEC tau siv nyob rau hauv drilling, ua tiav, workover thiab fracturing txheej txheem, feem ntau yog ib tug thickener nyob rau hauv brine, thiab nyob rau hauv ntau lwm yam kev siv.

HECcov khoom siv rau kev siv roj av

(1) Salt kam rau ua:

HEC muaj ntsev zoo heev rau electrolytes. Raws li HEC yog cov khoom siv uas tsis yog-ionic, nws yuav tsis raug ionized hauv dej nruab nrab thiab yuav tsis tsim cov nag lossis daus vim muaj cov ntsev ntsev ntau hauv lub cev, ua rau muaj kev hloov pauv ntawm nws cov viscosity.

HEC thickens ntau lub siab concentration monovalent thiab bivalent electrolyte daws, thaum anionic fiber linkers xws li CMC tsim salting tawm ntawm ib co hlau ions. Hauv kev siv roj av, HEC tsis cuam tshuam tag nrho los ntawm dej hardness thiab ntsev concentration thiab tuaj yeem ua rau cov kua dej hnyav hnyav uas muaj cov zinc thiab calcium ions siab. Tsuas yog txhuas sulfate tuaj yeem ua rau nws. Thickening nyhuv ntawm HEC hauv dej tshiab thiab saturated NaCl, CaCl2 thiab ZnBr2CaBr2 hnyav electrolyte.

Qhov kev tiv thaiv ntsev no muab sijhawm rau HEC los ua lub luag haujlwm tseem ceeb hauv ob qho tib si kev tsim kho qhov dej thiab ntug dej hiav txwv.

(2) Viscosity thiab shear rate:

Dej-soluble HEC dissolves nyob rau hauv ob qho tib si dej kub thiab txias, ua viscosity thiab tsim cov yas cuav. Nws cov tshuaj aqueous yog nto active thiab nyhav tsim foams. Cov kev daws teeb meem ntawm nruab nrab thiab siab viscosity HEC siv nyob rau hauv cov roj teb dav dav yog non-Newtonian, uas qhia txog qib siab ntawm pseudoplastic, thiab cov viscosity cuam tshuam los ntawm shear npaum li cas. Thaum qis shear npaum li cas, HEC molecules yog randomly teem, ua rau cov saw tangles nrog siab viscosity, uas txhim kho viscosity: nyob rau hauv siab shear npaum li cas, molecules ua oriented nrog ndlwg kev taw qhia, txo tsis kam mus ntws, thiab viscosity txo nrog qhov nce ntawm shear npaum li cas.

Los ntawm ntau qhov kev sim, Union Carbide (UCC) tau txiav txim siab tias tus cwj pwm rheological ntawm cov dej drilling yog nonlinear thiab tuaj yeem qhia tau los ntawm txoj cai fais fab:

Shear stress = K (shear rate)n

Qhov twg, n yog qhov ua tau zoo viscosity ntawm cov tshuaj ntawm tus nqi qis (1s-1).

N yog inversely proportional rau shear dilution. .

Hauv av nkos engineering, k thiab n yog qhov muaj txiaj ntsig zoo thaum suav cov kua dej viscosity zoo nyob rau hauv cov xwm txheej hauv qab. Lub tuam txhab tau tsim cov txheej txheem ntawm qhov tseem ceeb rau k thiab n thaum HEC (4400cps) tau siv los ua cov av nkos (table 2). Cov lus no siv tau rau txhua qhov kev daws teeb meem HEC hauv dej tshiab thiab ntsev (0.92kg / 1 nacL). Los ntawm cov lus no, qhov tseem ceeb sib xws rau nruab nrab (100-200rpm) thiab qis (15-30rpm) shear tus nqi tuaj yeem pom.

Kev siv HEC hauv roj teb

(1) Drilling kua

HEC ntxiv cov kua dej drilling feem ntau yog siv rau hauv cov pob zeb nyuaj drilling thiab nyob rau hauv cov xwm txheej tshwj xeeb xws li kev tswj cov dej tsis zoo, dej ntau dhau, qhov txawv txav, thiab cov txheej txheem tsis sib xws. Cov txiaj ntsig ntawm daim ntawv thov kuj yog qhov zoo hauv qhov drilling thiab qhov loj qhov drilling.

Vim nws cov thickening, ncua kev kawm ntawv thiab lubrication zog, HEC yuav siv tau nyob rau hauv drilling av nkos kom txias hlau thiab drilling cuttings, thiab coj tej kab rau saum npoo, txhim kho lub pob zeb nqa peev xwm ntawm cov av nkos. Nws tau siv nyob rau hauv Shengli oilfield li borehole kis thiab nqa cov kua nrog zoo kawg li thiab tau muab tso rau hauv kev xyaum. Nyob rau hauv lub downhole, thaum ntsib heev shear npaum li cas, vim lub cim rheological cwj pwm ntawm HEC, lub viscosity ntawm drilling kua yuav nyob rau hauv zos ze rau lub viscosity ntawm dej. Ntawm qhov tod tes, qhov drilling tus nqi yog txhim kho, thiab me ntsis tsis yooj yim rau cua sov, thiab kev pab cuam lub neej ntawm me ntsis yog ntev. Ntawm qhov tod tes, qhov drilled yog huv si thiab muaj permeability siab. Tshwj xeeb tshaj yog nyob rau hauv cov qauv pob zeb nyuaj, cov nyhuv no yog pom tseeb heev, tuaj yeem txuag tau ntau cov ntaub ntawv. .

Nws feem ntau ntseeg tau tias lub zog xav tau rau kev siv cov dej ntws los ntawm qhov muab faib feem ntau yog nyob ntawm qhov viscosity ntawm cov dej drilling, thiab kev siv HEC drilling kua tuaj yeem txo qhov kev sib txhuam hydrodynamic, yog li txo qhov xav tau ntawm lub twj tso kua mis. Yog li, qhov rhiab heev rau kev poob ntawm kev ncig kuj raug txo. Tsis tas li ntawd, qhov pib torque tuaj yeem txo qis thaum lub voj voog rov pib dua tom qab kaw.

HEC cov tshuaj poov tshuaj chloride tau siv los ua cov kua dej drilling los txhim kho qhov chaw zoo. Kev tsim tsis sib xws yog tuav hauv lub xeev ruaj khov kom yooj yim rau cov kev cai casing. Cov kua dej drilling ntxiv txhim kho pob zeb nqa lub peev xwm thiab txwv tsis pub txiav diffusion.

HEC tuaj yeem txhim kho adhesion txawm nyob rau hauv cov tshuaj electrolyte. Cov dej ntsev uas muaj sodium ions, calcium ions, chloride ions thiab bromine ions feem ntau ntsib hauv cov kua dej rhiab heev. Cov kua dej drilling no yog thickened nrog HEC, uas tuaj yeem khaws cov gel solubility thiab viscosity lifting muaj peev xwm nyob rau hauv thaj tsam ntawm ntsev concentration thiab hnyav ntawm tib neeg caj npab. Nws tuaj yeem tiv thaiv kev puas tsuaj rau thaj chaw tsim khoom thiab nce qhov drilling thiab roj ntau lawm.

Kev siv HEC kuj tuaj yeem txhim kho cov dej tsis zoo ntawm cov av nkos. Zoo heev txhim kho stability ntawm av nkos. HEC tuaj yeem muab ntxiv los ua ib qho ntxiv rau cov tsis-dispersible saline bentonite slurry kom txo cov dej poob thiab nce viscosity tsis muaj zog gel. Nyob rau tib lub sijhawm, kev thov HEC rau cov av nkos tuaj yeem tshem tawm cov av nplaum tawg thiab tiv thaiv kom tsis txhob tawg. Kev ua kom lub cev qhuav dej qeeb qeeb ntawm cov dej ntws ntawm cov av nkos ntawm phab ntsa borehole, thiab cov nyhuv ntawm cov saw ntev ntawm HEC ntawm cov pob zeb phab ntsa pob zeb ntxiv dag zog rau cov pob zeb thiab ua rau nws nyuaj rau hydrated thiab spalling, ua rau lub cev qhuav dej. Hauv cov txheej txheem permeability siab, cov dej tsis zoo xws li calcium carbonate, xaiv hydrocarbon resins lossis dej-soluble ntsev nplej yuav ua tau zoo, tab sis nyob rau hauv cov xwm txheej hnyav, kev daws teeb meem ntawm cov dej tsis zoo (piv txwv li, hauv txhua lub thoob ntawm cov tshuaj) tej zaum yuav siv tau

HEC 1.3-3.2kg) los tiv thaiv dej poob tob rau hauv thaj chaw tsim khoom.

HEC kuj tseem tuaj yeem siv los ua cov tshuaj tiv thaiv tsis muaj fermentable hauv cov av nkos rau kev kho kom zoo thiab kev kub siab (200 atmospheric siab) thiab ntsuas kub.

Qhov zoo ntawm kev siv HEC yog tias cov txheej txheem drilling thiab ua tiav tuaj yeem siv tib cov av nkos, txo qhov kev vam khom ntawm lwm cov dispersants, diluents thiab PH regulators, kua tuav thiab cia yog yooj yim heev.

(2.) Fracturing kua:

Nyob rau hauv cov kua fracturing, HEC tuaj yeem nqa cov viscosity, thiab HEC nws tus kheej tsis cuam tshuam rau cov roj txheej, yuav tsis thaiv cov pob txha tawg, tuaj yeem tawg tau zoo. Nws kuj tseem muaj cov yam ntxwv zoo ib yam li cov kua dej tawg, xws li cov xuab zeb muaj peev xwm ncua kev kawm ntawv thiab kev sib txhuam me me. 0.1-2% dej-cawv sib tov, thickened los ntawm HEC thiab lwm yam iodized ntsev xws li poov tshuaj, sodium thiab txhuas, tau txhaj rau hauv cov roj zoo ntawm qhov kub siab rau kev tawg, thiab cov ntws tau rov qab los hauv 48 teev. Dej-raws li fracturing kua ua nrog HEC muaj zoo tsis muaj residue tom qab liquefaction, tshwj xeeb tshaj yog nyob rau hauv formations uas tsis muaj permeability uas yuav tsis tau drained ntawm residue. Nyob rau hauv alkaline tej yam kev mob, lub complex yog tsim nrog manganese chloride, tooj liab chloride, tooj liab nitrate, tooj liab sulfate thiab dichromate daws, thiab tshwj xeeb tshaj yog siv rau proppant nqa fracturing kua. Kev siv HEC tuaj yeem zam qhov viscosity poob vim qhov kub ntawm qhov downhole siab, tawg tsam ntawm cov roj, thiab tseem ua tiav cov txiaj ntsig zoo hauv Wells siab dua 371 C. Nyob rau hauv downhole tej yam kev mob, HEC tsis yooj yim rau rot thiab deteriorate, thiab cov residue yog tsawg, yog li nws yuav pib tsis thaiv cov roj txoj kev, ua rau muaj kuab paug hauv av. Hais txog kev ua tau zoo, nws yog qhov zoo dua li cov kua nplaum uas feem ntau siv hauv kev tawg, xws li cov neeg tseem ceeb hauv teb. Phillips Petroleum kuj muab piv rau cov muaj pes tsawg leeg ntawm cellulose ethers xws li carboxymethyl cellulose, carboxymethyl hydroxyethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose thiab methyl cellulose, thiab txiav txim siab tias HEC yog cov tshuaj zoo tshaj plaws.

Tom qab cov kua fracturing nrog 0.6% hauv paus kua HEC concentration thiab tooj liab sulfate crosslinking tus neeg sawv cev tau siv nyob rau hauv Daqing oilfield nyob rau hauv Tuam Tshoj, nws tau xaus lus tias piv nrog rau lwm yam ntuj adhesions, kev siv ntawm HEC nyob rau hauv fracturing kua muaj qhov zoo ntawm "(1) cov kua hauv paus tsis yooj yim rau rot tom qab npaj, thiab tuaj yeem muab tso rau lub sijhawm ntev dua; (2) cov residue tsawg. Thiab tom kawg yog tus yuam sij rau HEC kom dav siv hauv cov roj zoo fracturing txawv teb chaws.

(3.) Ua tiav thiab ua haujlwm:

HEC cov kua dej ua tiav qis tiv thaiv cov av nkos los ntawm kev thaiv qhov chaw cia khoom thaum nws mus txog ntawm lub pas dej. Cov dej tsis zoo kuj tseem tiv thaiv cov dej ntau los ntawm kev nkag mus rau hauv lub reservoir los ntawm cov av nkos kom ntseeg tau tias lub reservoir muaj peev xwm tsim tau.

HEC txo cov av nkos, uas txo cov twj tso kua mis thiab txo lub zog noj. Nws zoo heev ntsev solubility kuj ua kom ntseeg tau tias tsis muaj nag lossis daus thaum acidizing roj Wells.

Hauv kev ua tiav thiab kev cuam tshuam, HEC lub viscosity yog siv los hloov pob zeb. Ntxiv 0.5-1kg HEC rau ib lub thoob ntawm cov dej ua haujlwm tuaj yeem nqa cov pob zeb thiab pob zeb los ntawm lub qhov borehole, uas ua rau zoo dua radial thiab longitudinal gravel faib downhole. Kev tshem tawm tom qab ntawm cov polymer zoo heev ua rau cov txheej txheem ntawm kev tshem tawm kev ua haujlwm thiab ua tiav cov kua dej. Qee lub sij hawm tsis tshua muaj, cov xwm txheej hauv qab yuav tsum tau kho kom zoo los tiv thaiv cov av nkos los ntawm kev rov qab mus rau lub qhov dej thaum lub sij hawm drilling thiab ua hauj lwm thiab ua kom cov dej poob. Nyob rau hauv cov ntaub ntawv no, ib tug high-concentration HEC tov yuav siv tau sai sai txhaj 1.3-3.2kg ntawm HEC ib chim ntawm dej downhole. Tsis tas li ntawd, nyob rau hauv qhov xwm txheej hnyav, kwv yees li 23kg ntawm HEC tuaj yeem muab tso rau hauv txhua lub thoob ntawm cov roj av thiab tso rau hauv cov ncej, maj mam hydrating nws thaum nws sib tov nrog dej pob zeb hauv lub qhov.

Lub permeability ntawm xuab zeb cores saturated nrog 500 millidarcy tov ntawm ib tug concentration ntawm 0. 68 kg HEC ib chim yuav rov qab mus rau ntau tshaj 90% los ntawm acidification nrog hydrochloric acid. Tsis tas li ntawd, HEC ua tiav cov kua dej uas muaj calcium carbonate, uas yog tsim los ntawm 136ppm ntawm cov neeg laus cov dej hiav txwv uas tsis tau lim dej, rov qab tau 98% ntawm tus thawj seepage tus nqi tom qab lub ncuav mog qab zib lim tau muab tshem tawm ntawm qhov chaw lim dej los ntawm cov kua qaub.