Laboratory Study of Formation Damage Under High Temperature and Pressure (Japan)

Abstract

Propertles of drllllng muds and formatlon damage of reservolr models under slmulated in-sltu geothermal condltlons. Propertles of bentonlte and seplorlte muds are measured by three klnds of apparatus. Propertles of muds by API speclflcatlons are tested at room condltlons after aglng for 24 hours UP to 250'C. Rheoloslcal propertles art? tested wlth a caplllary viscometer and Fann V-G meter model 50C under temperature. Two types of slmulated geothermal reservolr models are prepared to measure severlty of forrnatlon damage Induced by muds. One Is a fracture type model which conslsts of a sllt packed wlth sand gralns. The other Is a matrlx type model whlch comprlses a cyllndrlcal core of Berea sandstone, Measurements of forrnatlon damage are conducted up to 250T for the sllt models, and up to 200'C for matrlx model.Severe damage Is observed above 200% for both models. Hlgh temperature mud test Is useful to predlct formatlon damage.