CREATE TABLE tbl (ID int, fld_126 VARCHAR2(100) NOT NULL);
INSERT INTO tbl (ID, fld_126)
WITH rs AS (
SELECT 1, 'XWID9998887766XDEVmmmXZON8XPHN9998887766' FROM dual UNION ALL
SELECT 2, 'XDEVppppXWID999988877766XZON4XPHN9097976655' FROM dual
)
SELECT * FROM rs;
SELECT ID, j
, json_value(j, '$.XWID') as XWID
, json_value(j, '$.XDEV') as XDEV
, json_value(j, '$.XZON') as XZON
, json_value(j, '$.XPHN') as XDEV
FROM tbl t
CROSS APPLY (
SELECT treat(REPLACE('{' || REPLACE(REPLACE(REPLACE(REPLACE(fld_126
,'XWID','","XWID":"')
,'XDEV','","XDEV":"')
,'XZON','","XZON":"')
,'XPHN','","XPHN":"')
, '{",','{') || '"}' as json) As j FROM dual
) CrossApplied;