Modelling of formation damage due to particle invasion in relation to water injection schemes
This thesis dea1s with mode11ing of formation damage resu1ting from
invading s01ids, particu1ar1y in re1ation to water injection schemes
Where10wconcentration micron and sub-micron s01ids are concerned.
Ear1ier investigations were considered inadequate for study of formation
damagedue to partic1e invasion in manyrespects such as the nature of
damage, depth of damage characteristics and the inf1uence of various
parameters on the damagedata.
A porosity mode1(in 1inear and radia1 forms) based on mass ba1ance of
partic1es and a pore size distribution based 3Dcapi1lary network model
are presented. The network model uses various particle capture criteria
including a newprobability criteria to model particle retention.
The resu1ts from rock core based f10wtests are presented and ana1yzed.
The f10w tests were conducted on 00x25 •4na-dia. sandstone cores of
permeabi1ity range of 250 to 1000 md using 1-15 ppm concentrations of
O-3~ a1umina partic1es at flow-rates of 0.45-1.00 mils up to 150 hours
equiva1ent to over 40000 core pore v01umes. The experimental
invastigations showthe importance of depth of damageand 10ng duration
experiments on formation damagedata studies. Experimental permeability
shows si.mp1e semi-1og dec1ine with gross f10w ve1ocity. serious
occurs even for the 10w concentration systems. The
iBIporta.nce of core preparation is stressed, where the use of brok.en
faced cores is shown to be more appropriate for conducting partic1e
inv . .
as1.onexperuaents as comparedto the conventiona1 sa.wn-facedcores.
Both the porosity mode1and the network.mode1predictions are shownto
agree reasonab1y we11with the experimenta1 data.