Research On The Characteristic Of Donghe Sandstone In Well 1-18 Block,HDD Oil Field

Well 1-18 block is located in the northwest of the HDD oil field,which has been explored for more than ten years.Predecessors have been doing some efforts in geological condition,structural feature,sedimentary facies,physical property of the reservoir,3D geological model and so on,who have gained great success and breakthrough.But with the development of the research,plenty of practice data were enriched.Furthermore,there is a lot of problems,such as:Lots of diplog data were obtained in the program of exploring which wasn't used before;Many interlayers developed in the region but the awareness of which was limited,the standard of interlayer division was absence.At the moment,a lot of new wells were produced,there is much new well data need to be added in the 3D geological model so that the model could be adjusted.For the purpose of keeping high production,controlling oil and water and deepening the geological awareness,researching on the characteristic of Donghe Sandstone in well 1-18 block is necessary.In this paper,the geological property and the exploring data of well 1-18 block are used for the purpose of subzone division,diplog data exploration,sediment facies analyse,reservoir parameter interpretation,the relation of four properties,the research on the recognition and distribution of the interlayer,3D geological model,reservoir comprehensive evaluation.Some efforts were attained:The core and well logging data were used to identify the bed succession interface.In the light of the HR sequence stratigraphy,the Donghe Sandstone could be devided into one sequence,two metasequences and twelve subzones.The retrogradation sediment developed in the lower segment which was divided into seven subzones.The progradation sediment developed in the upper segment which was divided into five subzones.The layer of the Donghe Sandstone in this region turns thin from west to east and south to north.On the basis of the core description data,the diplog interpretation and core scale log,eleven diplog exploration models of representative bedding of the region were founded.The sedimentary facie of the Donghe sandstone in the region is shoreland fasie which can be divided into four intrafacies such as coast dune,backshore,foreshore and shoreface.According to the core data and the bedding model,the property of the intrafacies in the 1-18 well block could be researched detailed.The main intrafacies of the region are foreshore and backshore.The foreshore is located in the middle layer of Donghe sandstone while the backshore in the upper and bottom.But the number of coast dune is less and the thickness is thinner.After core depth migration and log curve standardization,the porosity and the permeability could be interpreted on the base of core physical property data and with the artificial neural network.The interpretation accuracy raised obviously.According to analyse the core,well log and test data,the relation of the four properties was obtained.The main lithology of the region is fine sandstone.The porosity and permeability of the reservoir are higher.The average of the porosity is thirteen points ninety percent,the average of permeability is 180×10^-3?m².The main oiliness level is oil immersion.In summary,the relativity of the four properties is good.The wider lithology,the better physical property,the higher oiliness level.According to the core and physical property data,the interlayer of the region could be classified as calcareous interlayer,argillaceous interlayer and cal-argillaceous interlayer.The standard of logging identification was founded after concluding the electrical property of these types of interlayer.The distribute of interlayer could be researched from vertical aspect,horizontal aspect and plane on the base of interlayer recognition of single well.The interlayer is thinner in the vertical aspect.The number of calcareous interlayer is much that these interlayers located mainly in the upper segment of Donghe sandstone.The argillaceous interlayers are often located in the lower segment.The number of cal-argillaceous interlayer is less.The number of the interlayer has no connection with the thickness of the sandstone.The consistence of the interlayers in horizontal aspect is poor and the thickness of the interlayers in the west is thicker than those in the east.In plane surface,the interlayer is located mainly in the northwest and southwest part of well 1-18 block,the number of interlayer in the east is less.The 3D structure model was founded on the base of geological characteristic,geostatistics and subzone division.Then,the sedimentary facies model was founded with the theory of sequence Gauss.Finally,the parameter models include porosity model,permeability model and water saturation model were founded by the sedimentary facies.The character of the reservoir parameters are indicated by these models,the accuracy of which is high.According to the condition of the data collection,the lower limit of the reservoir can be accounted with testing for oil,statistics and smallest radius of the pore throat.The lower limit is eight percent and the lower limit is 5.0×10^-3?m².The reservoir of the region could be divided into three types through the property of the hole,and the standard of reservoir division was established.Based on this standard,the reservoirs of single wells were evaluated.As an effort,the evaluation pictures of the single well,the well tie pictures and plane pictures were drew.In the vertical aspect,type?and type?reservoir located in the whole Donghe sandstone with the thickness of 0.5³ meters.The number of type?is less which lies in the lower segment generally.In the horizontal aspect,the connectedness of reservoir is better.In the plane aspect,type?is the main reservoir,which usually located in the backshore and foreshore where the porosity and permeability are higher and the sandstone is thicker.The area of type?mainly located in the backshore sediment with wide area.Type?lies in the edge of the region.As a whole,the property of the reservoir in upper segment of Donghe sandstone is better than that in lower segment.The development of the reservoir is controlled by the sedimentary facies.Type?located mainly in the foreshore sediment while type?and type?located in the backshore sediment.