| At present, Most of the domestic oil fields has been in the later stage with featureof the relatively high water cut and intensified decline of production to challengeNational energy security. In order to ensure Stable supply of energy,More effort isIntensified to develop maturing field or low grade oil sand for energy security. Thehydrocarbon reservoir assemblage of Huoshaoshan filed is in the mid-base ofPingdiquan group in Permian System with Total sediment thickness350to550m.There are4layer series of developments(H1、H2、H3、H4)which is classified bybarrier bed, cycle of sedimentation, mineral feature, electric property and so on.Although layer series of development H1developed earlier but the small scal becauseof the low-porosity,the low-permeability and the poor continuousReservoir.Nowdays,composite water cut is75.81%,degree of reserve recovery is4.58%,oil production rate is0.2%, liquid withdrawal rate is0.802%. The reservoir inlayer series of development H1of Huoshaoshan filed distribute skew like many lensand is tough block because of poor permeability.From development history,there arefour areas that reflecte the poor performance of development effectiveness.The first islow percent producing reserves.The second is low degree of water floodingcontrol.The third is low rate of oil production.The fourth is Rapid decline rate.In order to effectively improve and enhance the effect of H1-layerdevelopment,according to Reservoir characteristics and development effect, thedetailed geological study must be strengthened and the potential is developedeconomically and efficiently on this basis. The main purpose of this study is to carryout detailed reservoir description of H1layer, to improve the leve of recognition ofreservoir,to find out spatial distribution of sand and water-oil and to figure outgeological reserve more accurate.On the base of fine reservoir description,development effect is evaluated, matching producing history throughthree-dimensional geological modeling and numerical reservoir simulation to studyand analyse the distribution of oil remaining for Optimal adjustment programs. Thispaper has the following points from works: 1Though Core observation and logging response characteristics,2stable andvisible indicator horizons has been found. Seven small layers have been Divided baseon fine contrast of sedimentary cycle that are H11-1、H11-2、H12-1、H12-2、H12-3、H13-1、H13-2with rock-log mark of the top of each layer interface.2The structure of the study area is simple, The overall reservoir of HuoshaoshanH1is anticlinal structure, the long axis is9760m and short axis is3780m, Thedirection of long axis is NS. Implementation of one large fault (Huo10-wellfracture), implementation of one small fault (H1269well fracture) as well. From thedevelopment of micro-structural, it mainly developed48micro structure,19positivemicro structure, the29negative micro structure. Positive micro structures in the studyarea are with high levels of oil production, which followed by oblique micro-structure,the worst is the negative micro structure.3On the basis of the standardization of bore logs, by the core data return, theestablishment of the relationship between log data and core physical property analysisdata, drafting various interpretated model plats for determining the reservoirparameters. According to the research, which found that lithology of H1layerreservoir is sandstone, fine sandstone. The main reservoir porosity are in the range of4-20%, permeability0.003-400×10-3μm2. From the point of relationship betweenoiliness and lithology, indication of oil and gas are also concentrated in these twolithologic,except for oil-siltstone. From the relationship between lithology andphysical properties,grain size and porosity is nearly with no connection. mainlyaffecting the permeability, thicker the lithology, the greater the penetration.4According to the research analysis, H1layer of Huoshaoshan oilfield is a set ofdelta phase,which are delta front and prodelta subfacies deposition, land-based coarseclastic sediments. The sources are from the northeast of the beautiful carat mountain,showing that source supply is gradually weakened, and the evolution process ofdeltaic depositional is degenerated.5By the studies of heterogeneity,the pore types mainly are intergranulardissolution pores, intragranular dissolved pores, intergranular dissolution pores andsmall amount of intergranular pores. Inlayer heterogeneity are mainly types ofanti-rhythm, positive rhythm and homogeneous rhythm type. The inlayer andinterlayer heterogeneity of the upper four layers is relatively weak, the small layer inthe lower four part of the layer with relatively strong inlayer and interlayerheterogeneity. The average reservoir thickness are slight, the reservoir connectivity ispoor. Relatively, The connectivity of H12-2reservoir is well comparing with any otherareas. Other small layer of sand bodies distribute in the region like the shapes ofscattered potatoes.6Geological reserves of this field has increased2.11%,mainly due to thecalculation considering with geological reserve of Huo8area,in addition to littlechange of calculating parameters. 7According to analysis of the production rules for different blocks withdifferent development methods, which summed up the problems that the reservoir inthis region with low injector producer ratio, poor well pattern and heavy burden ofthe injection wells, low producing energy, decrease progressively and so on. The keyreason due to sand body plane of Huoshaoshan oilfield H1reservoir was distributedlens-shaped, with poor reservoir properties, low reserves abundance,for it is with nooverall development conditions.8Through analyzing monitoring data, coring data, dynamic analysis, numericalsimulation, feature of remaining oil saturation has been studied.The feature ofremaining oil saturation in H1vertically and horizontally has been summed up that themain layer is H12-2and has a greater potential for development.9Program adjustment has been taken regional governance with the northernregion developed and the southern region undeveloped. Adjustment of water injectionprofile,blocking off and perforations adding with old well, commingled productionwith bottom well have been taken to consideration in the northern region.The wellsproducing in bottom sand changing to H1or to commingled producing well, separateinjection well with water well or horizontal well drilling in selective region. theeconomic benefits of production Efficiency of horizontal well&perforations addingis better then vertical well&perforations adding and the degree of reserve recoveryreach to10.69%in next30years.The key issue of this paper is "finding the remaining oil, developing remainingoil",which associated the data of structure,deposition,reservoir,welllog,laboratory,development dynamics and so on, combined the dynamic and the static,analysed from the qualitative to the quantitative, mutual authentication, mutualinference, to be formed a valuable research idea and technical method which is fit forstudy on reservoir delicate description, distribution of remaining oil and raisingultimate recovery in production tail of grit reservoir development. It have beenprovided exploratory experiences of the efficient development for the similar maturereservoir. |
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