Sedimentary Cycles Division And Litho-Electric Characterization Of Conglomerate For Block Y921 In Yanjia Oilfield

In Dongying sag of Jiyang Depression, The conglomerate reservoirs of actic region with continental facies in faulted basin become more and more important with 42 blocks been found. Among them,25 blocks have been developed and producing OOIP has amounts up to 65.87 million tons. But due to such features as complicate sand, different standards to divide sedimentary cycles, fast lithology and facies change, low resolution in oil/water layers identification by conventional techniques, obvious heterogeneity and so on, there are great difficulties in development of them. So analyses of their features and brought out of appropriate characterization techniques are necessary for development of such reservoirs.On the basis of extensive investigation of sedimentation mechanism and characterization method of conglomerate reservoir of debris flow at home and abroad, through detailed core observation and description, field outcrops observation and description and comprehensive analysis of well logging and seismic data, taking Block Y921 of Yanjia oilfield as research target, sequence stratigraphic framework was established for the conglomerate development by reconstituting log, which can be used to research conglomerate reservoir seismic identification and description and depositional conglomerate division. And by the study of the sedimentary facies characteristics and distribution, log interpretation of reservoir conglomerate, effective evaluation research and so on; the macro, micro and distribution characteristics of conglomerate reservoir are researched. The main research results are as follows:1. It brought out a technique of conventional logs reconstruction calibrated under cores observation and image logs on conglomerate stage division. At the basis of calibration between core observation and image log, imaging-lithofacies interpretation chart and the identification model of stage interface of imaging well log innovatively are established and by reconstituting log, the correspondence of the lithology and electric property are determined and sedimentary stages of conglomerate are divided effectively. The conglomerate of the member 4 of Shahejie formation in Block Y921 is divided into three III stages, seven IV stages. Due to rising of waterlevel, each stage can be recognized as regradation.2. By observing and describing cores of 204.35m from five wells in Block Y921 of Yanjia oilfield, inshore subwater apron is developed and forms conglomerate reservoir of the member 4 of Shahejie formation in this area, which is divided into three subfacies:upper fan、middle fan and lower fan. Only deep wells can drill the lower fan. The reservoir of the middle fan is the thickest, which are also the most important oil and gas reservoir. In this area, the most effective reservoir are developed most in the braided channel microfacies.3. A useful evaluation method of the effective conglomerate reservoir and the log interpretation model on the base of different kinds of lithofacies is established. And the information of production performance proves the evaluation effectible. The conglomerate of the inshore subwater apron of the member 4 of Shahejie formation in Block Y921 is divided into four lithofacies assemblage, among which the first and the second ones are the dominant effective reservoir which are grew mainly in braded channels and front of middle fan.4. A new way is put forward innovatively that is "Permeability Profile Method" to evaluate reasonably the effectiveness of the reservoir in the same cycle using ratio between vertical permeability prominency areas and reservoir thickness, which solved the deficiency from conventional heterogeneity characteristics parameters and laid a good geological foundation for the study of the production by injecting water by stages.