During　the　drilling　process　of　fractured　carbonate　formations,　the　coexistence　of　well　kick　and　loss　caused　by　the　displacement　of　gas　and　liquid　gravity　often　leads　to　downhole　complexity,　difficulty　in　well　control　and　reservoir　damage.　In　this　study,　an　indoor　experimental　device　for　gas　and　liquid　gravity　displacement　is　created　to　simulate　the　coexisting　well　kick　and　mud　loss,　characterized　by　the　adjustable　key　parameters　such　as　fracture　size　and　drilling　fluid　performance,　automatic　data　acquisition　and　analysis,　displacement　process　visualization　and　so　on.　The　phenomenon　of　gas-liquid　gravity　displacement　is　simulated　using　this　new　device,　by　which　an　obvious　gas-liquid　interface　can　be　observed　in　fractures.　By　changing　the　fracture　width,　fracture　opening　degree,　drilling　fluid　viscosity,　bottom　hole　pressure　and　other　parameters,　this　paper　analyzes　the　characteristics　of　gas-liquid　gravity　displacement　in　fractured　formation.　The　results　show　that　the　loss　rate　increases　with　the　fracture　width　and　opening　degree　rising,　more　sensitive　to　fracture　width.　In　the　meantime,　the　increase　of　drilling　fluid　viscosity　has　an　obvious　suppression　effect　on　gas-liquid　gravity　displacement.　Based　on　the　results　of　laboratory　experiments,　the　preventive　measures　for　gas-liquid　gravity　displacement　are　proposed,　which　can　provide　references　for　safe　drilling　in　carbonate　fractured　formations.　©　2018,　Editorial　Office　of　ACTA　PETROLEI　SINICA.　All　right　reserved.