The Reservoir Characterization Of Saling Formation In Northern Block Of Lamadian Oil Field

Lamadian Oilfield is located at the northernmost of the DaqingPlacanticline,46°40′～46°50′N,123°53′～125°1′E. Its structure belongs to a threeorder structural belts of Daqing Placanticline.This oilfield, an asymmetry of short axisanticlines gas-cap reservoir under structural control, is a gas cap reservoir which issteep in the west and gentle in the east. The irregular reservoir distribution,thecomplex oil-bearing characteristics which has significantly different from othermembers of Lamadian Oilfield that bring difficulties in formation reserve parameters’design,reserve calculation and exploitation work of Sa0member.Stratigraphic division and comparison results, comprehensive and systematicanalysis of the core wells and well logging data is made in the study area. Basing onthe marker bed and with reference to the existing hierarchical data, fully withreference to the predecessors’, and fully consider the development pattern anddevelopment series of strata in the study area and reservoir heterogeneity anddifferences and relative stability between bed sets. Then in the strata division andcomparison of thin layers of the Sa0member,the method "cyclicity recessioncompare and hierarchical control" was used,the thin layers comparison of the800wells in the basic well net in the study area are accomplished which form the databasefile and draw46sections that includes9basic sections.The Sa0member of LamadianOilfield is divided into8sandstone formations and1mudstone interbed,thin layerdistribution is relatively stable,after stratum statistics the boundary of each thin layeris reasonable,which meet the demand of exploitation of Sa0member.According to the description of the reservoir characteristics such as sedimentarycharacteristics and reservoir property. The reservoir of Sa0member is delta frontdeposits under the lake transgression background.According to developmentcharacteristics and distribution of the sand body,the eight thin layers of Sa0member can be divided into three types which include scattered distribution type(Sa0Jia),band distribution type(Sa01,Sa04)and Stable distribution type(Sa02,Sa03,Sa05,Sa06,Sa07,Sa08).The depositional sub facies of this study area is confirmed bygrain size characteristics of several core wells.Then carry on research on thesedimentary characteristics of the800wells in this area which is used to draw singlewell sand body figure、 connecting-well sand body well and land horizontalmicrofacies distribution. The Sa0member is a reservior which oil storage ability andoil producing capability is not good.The interpretation for the thickness of gas bearingsand is on the basis of core data,by the means of log interpretation,based onproduction testing verification,with four properties as the main content.Synthesizeinduction and statistical to establish the lower limit standard.From the aspects oflithology, physical property, electric property,the standard of thickness interpretationon effective gas bearing sand、first-class gas bearing sand、second gas bearing sandin this block.Research shows that in Sa0member the layers that the drill meet are thedeposition of sandstone、muddy silt and mudstone.Reservoir and electrical resistancehas a good match that can reveal the sedimentary environment of reservoir by usingelectric logging curve.Based on the SP curve,comparison between inspection well andinterpretation result shows that the accuracy of sedimentary facies zone map andisopach map of sand body can reach above90%.Due to the differences of sedimentary conditions,Sartu reservoir group developthe sand body with complex shape、size and physical property which constitute thecomplicated relations of reservoir.Because of the differences and diversity of sandbody,the understanding of sand body depends on the degree of control of well patternon all kinds of sand bodies.Research on sand body of Sa0member and well spacingrelationship reveals that because of the underwater distributary channel sand body,thesand body boundary changes a lot after the first infill well pattern,with the furtureinfill,the outer boundary of the sand body tends to stable.After the third infill wellpattern,the boundary of the main sand body in the compound sand body turns moreclear,the scale of external front sand sheet turns smaller which show that separate form、lower thickness and types degrade.The drilling ratio of the sand body whichhas the better physical properties becomes lower.