If you want to grant to both tables and views try:
SELECT DISTINCT
|| OWNER
|| '.'
|| TABLE_NAME
|| ' to db_user;'
FROM
ALL_TAB_COLS
WHERE
TABLE_NAME LIKE 'TABLE_NAME_%';
For just views try:
SELECT
'grant select on '
|| OWNER
|| '.'
|| VIEW_NAME
|| ' to REPORT_DW;'
FROM
ALL_VIEWS
WHERE
VIEW_NAME LIKE 'VIEW_NAME_%';
Copy results and execute.