Thermal hnav thiab cobalt tshem tawm ntawm PDC

I. Thermal hnav thiab cobalt tshem tawm ntawm PDC

Nyob rau hauv lub siab sintering txheej txheem ntawm PDC, cobalt ua raws li ib tug catalyst los txhawb cov ncaj qha ua ke ntawm pob zeb diamond thiab pob zeb diamond, thiab ua rau cov pob zeb diamond txheej thiab tungsten carbide matrix ua ib tug tag nrho, ua rau PDC txiav hniav haum rau oilfield geological drilling nrog siab toughness thiab zoo heev hnav tsis kam,

Pob zeb diamonds kub tsis kam yog heev txwv. Nyob rau hauv atmospheric siab, nto ntawm pob zeb diamond tuaj yeem hloov pauv ntawm qhov kub ntawm 900 ℃ lossis siab dua. Thaum siv, ib txwm PDCs yuav degrade ntawm txog 750 ℃. Thaum drilling los ntawm cov pob zeb nyuaj thiab abrasive, PDCs tuaj yeem ncav cuag qhov kub ntawm qhov kub thiab txias, thiab qhov kub thiab txias tam sim ntawd (piv txwv li, qhov kub thiab txias hauv cheeb tsam microscopic) tuaj yeem siab dua, deb tshaj qhov melting point ntawm cobalt (1495 ° C).

Piv rau pob zeb diamond ntshiab, vim muaj cov cobalt, pob zeb diamond hloov mus rau graphite ntawm qhov kub thiab txias. Yog li ntawd, hnav ntawm pob zeb diamond yog tshwm sim los ntawm graphitization uas tshwm sim los ntawm kev sib txhuam hauv cheeb tsam. Tsis tas li ntawd, qhov thermal expansion coefficient ntawm cobalt yog siab dua li ntawm pob zeb diamond, yog li thaum lub sij hawm cua sov, kev sib txuas ntawm pob zeb diamond nplej tuaj yeem cuam tshuam los ntawm kev nthuav dav ntawm cobalt.

Xyoo 1983, ob tus kws tshawb fawb tau ua cov pob zeb diamond tshem tawm ntawm cov txheej txheem PDC pob zeb diamond txheej, txhim kho kev ua tau zoo ntawm PDC cov hniav. Txawm li cas los xij, qhov kev tsim kho no tsis tau txais kev saib xyuas nws tsim nyog. Nws tsis yog txog tom qab xyoo 2000 uas, nrog kev nkag siab tob ntawm PDC pob zeb diamond txheej, cov khoom siv laum pib siv cov thev naus laus zis no rau PDC cov hniav siv hauv pob zeb drilling. Cov hniav kho nrog cov qauv no yog tsim rau cov txheej txheem abrasive heev nrog cov thermal mechanical hnav thiab feem ntau hu ua "de-cobalted" cov hniav.

Lub thiaj li hu ua "de-cobalt" yog ua raws li txoj kev ib txwm ua rau PDC, thiab tom qab ntawd cov txheej txheem pob zeb diamond yog immersed rau hauv cov kua qaub muaj zog kom tshem tawm cov theem cobalt los ntawm cov txheej txheem kua qaub. Qhov tob ntawm cobalt tshem tawm tuaj yeem ncav cuag li 200 microns.

Kev kuaj hnyav hnyav tau ua rau ob qho tib si PDC cov hniav (ib qho uas tau raug tshem tawm cobalt kho ntawm pob zeb diamond txheej saum npoo). Tom qab txiav 5000m ntawm granite, nws tau pom tias hnav tus nqi ntawm PDC tsis-cobalt tshem tawm tau pib nce siab. Nyob rau hauv sib piv, cov cobalt-tshem tawm PDC tuav ib tug kuj ruaj khov txiav ceev thaum txiav kwv yees li 15000m ntawm pob zeb.

2. Kev txheeb xyuas txoj kev ntawm PDC

Muaj ob txoj hauv kev los kuaj xyuas PDC cov hniav, uas yog kev kuaj kev puas tsuaj thiab kev sim tsis muaj kev puas tsuaj.

1. Kev kuaj kev puas tsuaj

Cov kev ntsuam xyuas no yog npaj los simulate downhole tej yam kev mob raws li qhov tseeb raws li qhov ua tau los ntsuas qhov kev ua tau zoo ntawm kev txiav cov hniav nyob rau hauv cov xwm txheej zoo li no. Ob yam tseem ceeb ntawm kev kuaj kev puas tsuaj yog kev sim hnav tsis kam thiab kev ntsuas kev cuam tshuam.

(1) Wear resistance test

Peb hom khoom siv los ua PDC hnav tsis kam kuaj:

A. Vertical tshuab dhos (VTL)

Thaum lub sij hawm xeem, ua ntej txhim kho PDC me ntsis rau VTL tshuab dhos thiab tso ib lub pob zeb qauv (feem ntau granite) nyob ib sab ntawm PDC me ntsis. Tom qab ntawd tig cov qauv pob zeb nyob ib ncig ntawm lub tshuab dhos axis ntawm ib qho ceev. PDC me ntsis txiav rau hauv cov qauv pob zeb nrog qhov tob tshwj xeeb. Thaum siv granite rau kev sim, qhov kev txiav qhov tob no feem ntau tsawg dua 1 hli. Qhov kev sim no tuaj yeem yog qhuav lossis ntub. Hauv "kev sim VTL qhuav," thaum PDC me ntsis txiav los ntawm pob zeb, tsis muaj cua txias; tag nrho cov kev sib txhuam kub generated nkag mus rau hauv PDC, accelerating graphitization txheej txheem ntawm lub pob zeb diamond. Txoj kev sim no tau txais txiaj ntsig zoo thaum ntsuas PDC cov khoom nyob rau hauv cov xwm txheej uas yuav tsum tau muaj siab drilling siab lossis kev sib hloov ceev.

Qhov "ntub VTL xeem" kuaj pom lub neej ntawm PDC nyob rau hauv cov cua kub nruab nrab los ntawm kev txias PDC cov hniav nrog dej los yog cua thaum lub sij hawm sim. Yog li ntawd, lub ntsiab hnav ntawm qhov kev sim no yog kev sib tsoo ntawm cov qauv pob zeb es tsis yog qhov cua sov.

B, kab rov tav tshuab dhos

Qhov kev sim no kuj tau ua nrog granite, thiab lub hauv paus ntsiab lus ntawm kev xeem yog qhov pib zoo ib yam li VTL. Lub sij hawm xeem tsuas yog ob peb feeb xwb, thiab cov thermal shock ntawm granite thiab PDC cov hniav yog tsawg heev.

Cov kev ntsuas granite siv los ntawm PDC cov khoom siv yuav sib txawv. Piv txwv li, qhov ntsuas tsis siv los ntawm Synthetic Corporation thiab DI Company hauv Tebchaws Meskas tsis zoo ib yam, tab sis lawv siv tib yam khoom siv granite rau lawv qhov kev xeem, ntxhib mus rau qib nrab polycrystalline igneous pob zeb nrog me ntsis porosity thiab compressive zog ntawm 190MPa.

C. Abrasion ratio ntsuas ntsuas

Raws li cov xwm txheej tau teev tseg, cov pob zeb diamond txheej ntawm PDC yog siv los txiav cov silicon carbide sib tsoo lub log, thiab qhov sib piv ntawm kev hnav tus nqi ntawm kev sib tsoo lub log thiab tus nqi coj ntawm PDC yog coj raws li qhov hnav ris tsho ntawm PDC, uas yog hu ua hnav piv.

(2) Impact resistance test

Cov txheej txheem rau kev ntsuam xyuas cuam tshuam nrog rau kev txhim kho PDC cov hniav ntawm lub kaum sab xis ntawm 15-25 degrees thiab tom qab ntawd tso ib qho khoom los ntawm qhov siab kom ntaus pob zeb diamond txheej ntawm PDC cov hniav ntsug. Qhov hnyav thiab qhov siab ntawm cov khoom ntog qhia txog qhov cuam tshuam lub zog uas tau ntsib los ntawm kev kuaj hniav, uas tuaj yeem maj mam nce mus txog 100 joules. Txhua tus hniav tuaj yeem cuam tshuam 3-7 zaug kom txog thaum nws tsis tuaj yeem kuaj ntxiv. Feem ntau, tsawg kawg 10 qhov qauv ntawm txhua hom hniav raug kuaj ntawm txhua qib zog. Txij li thaum muaj ntau yam hauv kev tiv thaiv ntawm cov hniav rau kev cuam tshuam, cov txiaj ntsig ntawm txhua qib zog yog qhov nruab nrab ntawm pob zeb diamond spalling tom qab cuam tshuam rau txhua tus hniav.

2. Kev sim tsis muaj kev puas tsuaj

Feem ntau siv cov txheej txheem kuaj tsis muaj kev puas tsuaj (tshwj tsis yog kev tshuaj xyuas qhov muag thiab microscopic) yog ultrasonic scanning (Cscan).

C scanning thev naus laus zis tuaj yeem kuaj xyuas qhov tsis xws luag thiab txiav txim siab qhov chaw thiab qhov loj ntawm qhov tsis xws luag. Thaum ua qhov kev sim no, ua ntej tso PDC cov hniav hauv lub tank dej, thiab tom qab ntawd luam theej duab nrog ib qho ultrasonic sojntsuam;

Kab lus no tau luam tawm los ntawm "International Metalworking Network“