In　flow　assurance　of　crude　oil　pipeline　transportation,　pig　stalling　and　wax　blockage　in　pigging　could　cause　complete　shutdown　of　the　whole　pipe.　In　consequent　wax　remediation,　thumb　rules　of　the　operators　usually　play　a　crucial　role　due　to　the　lack　of　theoretical　understanding　of　wax　removal　and　accumulation　mechanisms.　Therefore,　learning　from　previous　wax　remediation　practices　becomes　necessary　to　avoid　these　accidents.　In　response,　this　paper　extensively　surveys　multiple　field　pigging　operations　and　summarizes　the　experience　and　lessons　obtained　from　these　incidents.　Several　typical　scenarios　such　as　long-unpigged　pipe　and　back　flow　in　pig　rescue　are　investigated.　Some　puzzling　phenomena　where　the　pig　moves　in　front　of　the　wax　plug　and　occurrence　of　wax　blockage　without　pigging　are　also　analyzed.　The　drawn　experience　and　lessons　could　be　helpful　in　scheduling　pigging　program　and　enhancing　the　security.