Study On Stratigraphic Classification In Es-4 North Slop Of Dongying Sag

The actic region of northern Dongying sag is rich in glutenite. The structural complexity of glutenite body and distinct reservoir heterogeneity caused by fault activities makes the stratum lithology and electrical characteristic of Sha 4 member of the Sag unconspicuous and increases the changes in velocity of strata. Thus it is a controversy about stratigraphic division, glutenite location and seismic axis interpretation in Sha 4 member. Based on the sequence stratigraphic theory and selecting 10 typical wells from more than 60 exploratory wells with abundant data and complete stratums, the dissertation focused on the stratigraphic division of Sha 4 member by analyzing their lithology, electrical characteristic and paleontology information comparatively and combining with their VSP data or synthetic seismograms.comprehensive investigations of glutenite reservoirs on drilling, logging, seismic data and calibration.Through tracing the seismograms in the sequence from Lijin southern, the northern, Shengtuo to Minfeng sub-sag, it is found that the seismic axis of T6, T7 and under T7 are consistent.At last, by the means at regional scale, statistics to stratums and stratigraphic correlation in 4th member of Shahejie Formation of some backbone wells are compared and relative seismic sections are interpreted. The results verify that distinguishing stratums and tracing seismograms in these typical wells are correct. As follows is the main conclusion of the article:(1). The results of analyzing depositional environment in Sha 4 member of the area show that the pure salt and gypsum layers of Lijin, Shengtuo and Minfeng exist steadily in areal geology, and The lays are corresponding to the red lays lying in the location of the nether Es4. Based on these, we can advance that the top of Salt and gypsum layers is continuous, and it is the boundary between the upper and the nether of Es4. (2). The reservoir characteristic of petrology and logging geology in north belt of Dongying depression is following:Most of the nether of Es4 distribute Salt and gypsum layers.The main kinds of lithology of Chx are plumbeous mudstone and gray mudstone, and some mudstone containing gypsum is found that their resistances are high.The most lithology of Chs are gray mudstone and calcareous mudstone.It's possible to find bad oil shale, but no mudstone containing gypsum. The line of GR is high too.There is lamella dolomite and no limestone in the upper Es4.(3). By means of studying stratigraphic correlation and Seismic profile, a new understanding about the lays contribution in landscape orientation, lithology and electrical characteristics in Sha 4 member of the area is found.