Hi ,
For Service order search, This the FM being used-CRM_BSP_OIC_1O_SEARCH_FROM_RF,Just do a trace in the FM you ll get to know the REQ authorization object.
Some Auth which i know for service order search....
B_BUPA_RLT
B_BUPA_GRP
CRM_ORD_OP
CRM_ORD_PR
PLOG