The Reservoir Simulation Of Stream Flooding And Dynamic Monitoring For The Es₄4 Of Cao4 Section

With the reduction of conventional oil recoverable reserves,heavy and low permeability oil reservoirs become the focus of developing under current economic and technological conditions;where abundant heavy oil resources in the world,up to15500×10⁴t,which is 3.7 times more than conventional crude oil reserves.Currently,conventional thinking of heavy oil recovery is to turn to steam flooding,after the deterioration of effectiveness and economic benefit during steam huff and puff.The Es₄4 reservoir of Cao4 section,oil-bearing area 5.25km²,proven oil reserves of607.68×10⁴t,was developed by huff and puff in the year of 2005,with the well pattern200m×283m.Throught the average 8 cycles,the annual decline rate reached 10.5%with the pressure drop 6.5MPa and the predicted recovery will only be up to 18.51%.In order to enhance the recovery widely,the pilot test was carried out in 4 well groups in 2014,but the initial development effect was not quite satisfied.This paper,based on the geological study of Es₄⁴ reservoir of Cao4 section,focus on the reservoir geological and numerical simulation model of steam flooding well area,and the dynamic characteristics of the reservoir,then,the analysis of production performance are carried out,and it come out that the remaining oil is mainly in the interwell area and upper formation.And the conclusion was draw that the main factors leading to unsatisfied development was the lower steam quality and major well spacing.Ultimately the technical and economic optimal solution of well patterns was determined,respectively the corner-well injection conversion and the well network infilling in the form of steam flooding,and when the steam dryness above 0.85,production injection ratio of 1.1,appropriately increasing liquid production rate about 25%,which can obtain higher recovery degree and oil steam ratio;when crude oil prices above$70,the well network infilling for steam flooding can be carried out and its end of the decade the degree of reserve recovery will be up to 52.58%,oil steam ratio up to 0.197.