Evaluation And Potential Excavation Technology Research On Non-chief Thin Oil Formation Of Middle First Block In Gudao Oilfield

The Guantao upper formation in Gudao oilfield is fluvial facies reservoir,thin oil formation develops and its reserves is 23.2 percent of Gudao oilfield reserves. It is often produced with chief thick oil formation and has serious interlayer interference problem,which causes bad production effect and lower recovery percentage of OOIP,so it has big potential and is the importance guarantee of late production. The paper takes example for middle first block Ng5-6 sands group,stressing 3～4 meter oil formation geology research. First,on the basis of differentiate standard,water flooded interval judge standard and classified appraise standard of thin oil formation, sedimentary unit is classified by means of study on cycle of sedimentation,isopach and isobath,sophisticated classification and correlation is carried , combining results with production to furthermore reasonable classification. Secondly , it studied plane sedimentary micro-facies distributing , using rich log and sand core data , and reservoir heterogeneity from plane,interlayer,in-layer three aspects to furthermore fine describe the reservoir. Thirdly,it founded fluid model according to fluid property and variational rule. According to above results,it rebuilt stratum,structure,reservoir,fluid and oil deposit 3-D geology model of middle first block Ng5-6 reservoirs , external reflecting complex reservoir geology disciplinarian and oil and water distributing disciplinarian. On the basis of result,it matched performance history,using petroleum reservoir engineering and numerical reservoir simulation methods,forecasted its oil recovery and evaluated its development effect. Then it studied every layer reserves employed status and remaining oil distribution and potential excavation from flow base and separateness production base etc. Considering current well pattern,it built screen standard of thick formation horizontal well and optimized horizontal well each productivity parameters,which main include the position of the horizontal well and length of horizontal section,and then forecasted the productive capacity.Now,there are 6 horizontal wells put into production in middle first block Ng5-6,extending application 4 horizontal wells in Ng1+2 block. Field application achieved good results,under the background of composite water cut is up to 93.7%,initial oil production rate of horizontal well is up to 15 t/d,3-4 times more than the vertical wells around,and composite water cut is 87%,6- 10% lower than the vertical wells around,accumulative oil is 12.57×104t,providing important reference significance for enhanced the oil recovery and potential excavation work aftertime.