Experimental Research About High-Concentration Polymer Flooding In North-West Area Of LaMaDian Oilfield

Petroleum　is　not　only　a　kind　of　non-regenerative　resource,　but　also　the　crucial　economic　vital.　With　the　exploitation　of　oilfield,　especially　when　the　water　cut　of　reserves　is　high,　both　the　economy　index　and　technique　index　will　get　worse.　The　water　cut　of　oil　well　increases,　the　oil　production　decreases,　and　the　constructive　investment　and　cost　increase.　How　to　exploit　the　residual　oil　in　the　reservoirs　efficiently　after　water　flooding,　which　approximately　accounts　for　60~70%　reserves　in　place,　is　the　main　task　of　petroleum　engineering　experts　in　the　whole　world.　Polymer　flooding　and　 ASP　technology　have　acquired　obvious　effectiveness　in　Daqing　Oilfield,　but　simultaneous　faced　some　new　problems　in　practical　production,　such　as　the　increasing　of　polymer　injection　pressure　and　 flowing　resistance,　which　aggravate　the　imbalance　between　injection　and　production.　In　the　first　place,　although　the　recovery　of　ASP　flooding　can　attain　to　20%OOIP,　technology　complication,　investment　greatness,　and　the　technology　is　in　immature　stage;　In　the　second　place,　the　existence　of　alkali　in　ASP　flooding　not　only　need　to　increase　the　concentration　of　polymer　solution　but　also　decreases　the　viscous-elastic　character　of　polymer,　which　decreases　the　oil　recovery　of　ASP　flooding.　In　the　third　place,　the　existence　of　alkali　in　ASP　flooding　result　in　the　emergence　of　high　viscosity　w/o　 emulsion　which　influents　production　ability　of　oil　well,　 increases　the　difficulty　of　emulsion　breaking.　In　addition,　the　scale　of　the　reservoirs　and　wells　because　of　alkali　also　make　great　influence　on　the　oilfield　production.　Usually,　the　injection　pressure　improvement　with　the　increasing　of　concentration　and　molecular　weight　of　polymer,　which　limits　the　polymer　concentration　used,　and　ASP　flooding　effect　will　go　bad.　The　original　research　believed　when　the　polymer　dose　is　constant,　the　change　in　polymer　injected　PV　and　concentration　does　not　increase　oil　recovery　obviously.　While　the　results　of　the　lab　researches　revealed　that　the　recovery　of　high　concentration　and　high　molecular　weight　polymer　flooding　can　reach　or　over　ASP　recovery.　High-concentration　polymer　flooding　is　an　important　measure　of　tapping　the　potential　of　polymer　flooding　and　enhancing　the　economic　efficiency,　but　the　theoretical　and　practical　researches　in　this　aspect　are　somewhat　lagging.　The　research　paper　study　the　performance　and　flow　parameter　of　high　concentration　polymer　system　and　optimize　the　oil　flooding　conditions.　The　main　aim　is　obtain　a　new　kind　of　method　that　can　enhance　the　badly　heterogeneous　and　high　permeable　oil　reservoirs'　recovery,　which　can　take　the　place　of　the　ASP　flooding　and　tap　the　stimulation　oil　potential　of　polymer　flooding　technology,　improve　the　oil　displacement　effect,　decrease　the　cost,　enhance　oil　recovery.　The　success　of　the　new　method　has　an　important　strategic　significance　on　effectively　and　economically　developing　and　utilizing　oil-mineral　resource,　remaining　the　oilfield　lasting　development　towards　high　level　and　high　efficiency.