| Zhuang52 block is located in the key development zone in the east sub-depression of Gubei Sag in Zhanhua Sag,and the I oil group of the lower member of Shahejie Formation is an important oil-producing layer in the work area.At present,there are some problems in Zhuang52 reservoir,such as large interlayer difference,low oil production rate and unclear oil-water relationship,which seriously affect the development and production.Based on drilling,logging,core data and previous achievements,this paper conducts a detailed study on oil layer correlation,sedimentary microfacies analysis,oil layer physical properties and distribution characteristics under the control of high-resolution sequence framework of the I oil group of the lower member of Shahejie Formation in Zhuang52 block,which lays a foundation for subsequent development and adjustment.Firstly,according to the logging response,controlled by the base-level cycle in high-resolution sequence stratigraphy,the medium-term and short-term base-level cycles of I oil group in Zhuang52 block are identified,Determining the high-frequency sequence division scheme,a total of 1 medium-term base-level cycle,4 short-term base-level cycles and 8 short-term base-level semicycles are identified.Based on this scheme,they are divided into 1 oil group,4 sand groups and 8 sublayers,thus determining the oil layer under the control of high-frequency sequence.Taking this as a unit,carry out high-frequency sequence and oil layer correlation in the whole region,and clarify the spatial distribution characteristics of oil layers.Secondly,on the basis of reservoir division and correlation,combined with logging and core data,the sedimentary microfacies and characteristics under the high-frequency sequence stratigraphic framework are studied.It is determined that there are four types of sedimentary microfacies in the study area:turbid water channel,channel flank,sheet sand and inter-channel.It is believed that the study area mainly develops braided channels and turbidite sheet sand in the sublacustrine fan,and the progression-retrogression of the fan body from bottom to top is obvious.Through the analysis of single well facies,profile facies and the compilation of sedimentary facies plan,the development and distribution characteristics of sedimentary facies in the vertical and plane within the high-precision sequence framework are analyzed,and it is pointed out that the overall performance of the study area is that the turbidity water channel and sheet sand of the early I4 sand group are basically undeveloped,and the deep lacustrine muddy deposits are the main ones;the sublacustrine fan bodies of I3,I2 and I1 sand groups are distributed in contiguous areas,among which the turbidity water channel of I2 sand group has the largest sedimentary thickness,the sheet sand contiguous develops in the front end of the channel,and the sublacustrine fan of I1 sand group shrinks.Finally,through core calibration,the porosity and permeability parameters of logging data are calculated and the reservoir physical properties of the target interval are analyzed.It is considered that the I oil group belongs to a medium-porosity and medium-low permeability reservoir,and the intralayer heterogeneity,the interlayer heterogeneity and plane heterogeneity is serious.Physical properties have obvious facies control characteristics.Braided river channel has strong heterogeneity and medium permeability;The permeability of turbidite sheet sand is relatively good.Based on the above analysis,and according to the distribution law of oil layers,the development and adjustment suggestions of Zhuang52 block are given. |
PDF Full Text Request