Research On Water Invasion And Distribution Of Remaining Oil In The Later Stage Of Cyclic Steam Stimulation In Jin 91 Block

Jin 91 Block,medium thick interbedded,is a typical heavy oil reservoir with edge and bottom water.It was produced in 1984,till now,after 17.2 average cyclic steam stimulation(CSS)cycles,the block enters the late stage of CSS with declining production performance.Periodic oil-steam ratio is 0.19,average daily oil production of single well 1.2t/d,formation pressure 2.0MPa,all the indexes will reach the economic limit of CSS,therefore,it is urgent to abandon CSS and converse development mode.Yu I Formation of Jin 91 Block,a pilot area,produced in late May,2008,obtaining a better effect,proving that steam drive is suitable for the Block,and is planned to conduct scale application in Jin 91 Block.However,due to strong heterogeneity,after many years huff and puff,the areal and vertical water invasion is serious,lacking knowledge of distribution regularity of remaining oil,hindering the design of layer(scale steam drive)and well pattern.Therefore,we launch “Research on water invasion and remain oil distribution in Yulou oil layer of Jin 91 Block” to provide technical support for further development of targeted reservoir.The paper studies development characteristic of different well spacing(83m,118 m and 167m),including the regularity of periodic variation of oil production,oil-steam ratio,water recovery rate,and production time.Meanwhile,we also analyze other effecting factors,such as,position of water inversion structure,permeability directivity,injection-production ratio,producing time,geological factor,development factor,and conduct research on regularity and characteristic of areal and vertical water invasion,analyzing the impact of various factors on distribution of remaining oil,for example,areal and vertical produced degree,geological factor,thermal recovery technique,well deployment of each member in Yu I Formation,and the potential area of each member is Yu I Formation.The above study provides support for further scale application of steam drive.