| Aiming at the problems existing in H horizontal well area,such as the rapid inrush of injected water along hydraulic fracturing,high water cut,low overall water injection.utilization efficiency and poor development effect,on the basis of dynamic evaluation,this paper proposes an asynchronous injection-production mode for fractured horizontal wells and vertical wells,and analyses the characteristics of oil-water flow in three stages of water injection,soaking wells,oil production and four stages of production cycle.The research shows that the horizontal-vertical asynchronous injection-production can give full play to the imbibition of injection water and matrix,utilize the remaining oil in matrix,change the direction of injection water displacement,expand the efficiency of water flooding and improve the effect of water flooding development.Based on the actual data of H horizontal well area and reservoir engineering and numerical simulation methods,the effects of fracturing parameters such as fracture half-length,fracture spacing,fracture conductivity and injection-production parameters such as soaking time,water injection rate and fluid production rate on cumulative oil production by asynchronous injection-production in multi-stage fractured horizontal and vertical wells are analyzed.The optimum fracture half length is 125 m,fracture spacing is 60 m,fracture conductivity is 60*10-3μm2·m,soaking time is 10 days,periodic daily water injection volume is 36 m3,daily fluid production volume is 32 m3.The preferred fracturing and injection-production parameters were applied to the HP8 well group,and the development indicators for production for 10 years were simulated and calculated.The results show that the daily oil production of HP8 well increased rapidly from less than 1m3 to about 7.5 m3,and the water content decreased from 95%to about 75%.It is estimated that the cumulative oil production in 10 years will increase by 22,350 tons,and the yield increase effect is obvious.At the same time,use the development and adjustment measures such as water injection adjustment,oil well transfer and shut-in,well network encryption,acidification and plugging of water injection wells,profile control and water shutoff,subdivision water injection,etc.It is estimated that the cumulative increase of production will be 5.61*104t and the recovery rate will increase by 1.8 after the implementation of the adjustment plan,among them,the production increased by horizontal-vertical asynchronous injection-production mode is about 4.07*104t,accounting for 72.5%of the total oil increment,which expected that the asynchronous injection and production measures of different wells are the main factors for oil increase in this development.The work of this paper not only provides technical support for water injection development in H horizontal well area,but also provides important technical reference for water injection development and adjustment of horizontal well area in low permeability reservoir. |
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