致密油储层增能压裂裂缝起裂及扩展规律
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中图分类号：P74；TE28 文献标志码：A 文章编号：1000-7393（2025）-04-0511-11
Abstract：Pre-injectionofwatertoenhanceenergyintightoilreservorsisanefective meansofsupplementingformationenergyand improvingtheefectivenessoffracturingtreatmentPre-ijectionofnergyenancingfluidisofgreatsignificancefortheiitiation andpropagationofsubsequentfracturingfracturesintightoilreservoirs.Thestudyusedalarge-scaletruetriaxialfacturingphysical simulatinsystem toconductfracturingphysical modelexperimentsunder formation pressureconditions basedonartificialtight sandstonerock samples.Combined with acoustic emision monitoring during thefracturing processand surface crack morphology afterfracturing，themechanismof enhanced fracturingrock fractureandexpansionwasstudied.Theresearchresultsindicate that injecting water before pressrecan increasethepore pressureofrock samples near theperforation location，resulting ina 7.1% increaseinfracturepresure.Theacousticemisioneventsofconventionalfracturingetodsareconcentratedbeforeandafterthe rock sample fractures，while there is anacoustic emisionresponse during the energy enhancement stage before the fracturing presure.Theacousticemisioneventsbeforeandafterthrocksamplefracturesduetotheformationofmicrocracksareelatively scatered.Convetioalfacturingacousticemisioneventsaremanlycharacteredbytensilefractures，withelatielysmplecacks. Energy enhanced fracturing fractures have complex bending， with a 11% increase in the proportion of shear events compared to conventionalfracturing.Sheareventsaremainlydistributednearthe tumingandbranchingoffractures.Themicrocracksgeneratedby energy enhancement beforecompresion open under high displacement，formingacomplex fracturenetwork through hydraulic fracturing. The hydraulic fracture complexity coefficient of the rock sample increases by 105% before and after energy enhancement athighdisplacement.Theconclusionindicates thatpre-fracturing waterinjectionforenergyenhancementcansignificantlyincrease thecomplexityofhydraulicfractures intightsandstonereservoirs.Thesefindings provideimportant teoreticalsupportand practical guidance for the optimization design and field application of enhanced energy fracturing technology.
Key words： tightoil reservoir; enhanced fracturing; fracturingexperiment;acousticemisionmonitoring; fracture propagation
0 引言
松辽盆地致密油藏储量丰富，可采资源量达2.72×108t[1] ，占我国陆相致密油资源总量的18.7% ，已成为国内原油增储上产的重要力量［2」。（剩余17626字）
