Study On The Interlayers And Intercalations Of Wutonggou Formation In Lukeqin Oilfield

Lukeqin oilfield locates in the western dense well area of Lukeqin area in Turpan Hami basin.Permian Wutonggou formation is its main oil-bearing series.Wutonggou formation is devided into three oil members and sandy conglomerate mainly develop in it.The flow and distribution of oil in the reservoir are influenced by the existence of interlayers and intercalations in the reservoir.At present,the research area has not been carried out on the identification and distribution of the interlayers and intercalations,thus seriously hindering the future development of the oilfield.Based on core data,well logging data and production data,studied the classification,causes,identification standards,distribution and the effect on reservoir development of interlayers and intercalations of representative third member of Wutonggou formation.The main conclusions and achievements are as follows:(1)Pointed out the reservoir characteristics of Wutonggou formation in Lukeqin oilfield.Found that the main lithology of Wutonggou formation is sandy conglomerate,followed by fine sandstone.Diagenesis includes compaction,cementation and dissolution,etc.The space type of reservoir is dominated by residual intergranular pore and dissolution pore,and the pore connectivity is good.(2)Interlayer types of Wutonggou formation in Lukeqin oilfield is devided and various types of interlayer causes are revealed.Muddy interlayer,calcareous interlayer and silty sand interlayer are the main types here.The cause of the interlayers is related with deposition and diagenesis.The muddy interlayer and silty sand interlayer are formed by deposition,calcareous interlayer and silty sand interlayer are formed by diagenesis.(3)The well logging response characteristics of the three types of interlayers of the study area are different.The quantitative identification standards of interlayers were established by using natural potential,natural gamma,resistivity and acoustic time well logging curve.The recognition results are verified by the results of core observation,founding that for thicknesses larger than 0.5m interlayer recognition effect is more ideal.On the whole,the recognition rate is 82.33%,and the recognition result is ideal,which solved the problem of the non coring wells interlayer recognition.(4)The distribution law of interlayers of Wutonggou formation in Lukeqin oilfield is illustrated.The study found that interlayer distribution is controlled by sedimentary facies and consistent with the direction of the river.Made the interlayer model of main layer of study area.Sum up the spatial distribution law of interlayers in conglomerate reservoir.Found that the distribution of interlayer is controlled by sedimentary facies and structure,the muddy interlayers appear in the side of the river,the silty sand interlayers and the calcareous interlayers appear in the main body parts of the river.(5)The influence of interlayers on reservoir development is proclaimed.The study found that stable interlayer effectively prevents fluid gravity differentiation,and avoids the connection between upper and lower sand bodies,enhanced the effect of layer production.The existence of interlayer increases the heterogeneity of the reservoir,which makes negative displacement effect of the injected water on the remaining oil.The oil in the lower part of the interlayer is blocked by the interlayer,and the remaining oil enrichment area is formed.