Logging Reservoir Evaluation Of The Palaeozoic In The East Slope Of Central Palaeo-uplift Of Ordos Basin

In recent years, the exploration and development of gas reservoir have made the unprecedented progress in Ordos basin, its reservoir precise analysis and the appraisal appears especially importantly, but the log information is the reservoir appraisal important method. The paper through the east slope of central palaeo-uplift reservoir research to Ordos basin, has established the logging reservoir parameter explanation model, effectively has carried on the reservoir logging appraisal.In this research, the reservoir of Palaeozoic is evaluated by the basic geological data, using the various modem experiment and technical methods of reservoir evaluation such as observating core,casting slice, electron microscope scan and analysis of mercury penetration, has carried on the geological reservoir appraisal to this area Paleozoic reservoir, in this base, the application log information and the base geological data, established the logging parameter interpretion model of low-permeable gas reservoir and the way of identify gas horizon . According to the idea that analize the formation from single-well to multi-wells, evaluated the reservoir. As the conclusions follow:First, the Upper Paleozoic reservoir mainly is in Shihezi formation and Shanxi formation, Shihezi formation lithological character mainly for debris quartz sandstone, contains the few pebble. Shanxi formation reservoir does not grow, the rock compact, the shale content is high. The Lower Paleozoic reservoir is Majiagou formation's putty crystal dolomite and powder crystal dolomite primarily.Second, the porosity and the permeable of Paleozoic reservoir are low. Shihezi formation reservoir is higher than Shanxi formation equally.Third, the pore type of the Upper palaeozoic group reservoir including between primary pore, corrosion pore, intercrystalline pore and secondary pore. The Lower Paleozoic reservoir mainly by corrosion pore, intercrystalline pore and the crack are composed.Forth, identifition based on log data character to select adapt modle and parameter, identify availability characters of reservoir's liquid. When reservoir has gas, acoustic time increase, density and neutron porosity depress, to porosity curve separate, concluding gas horizon. From the transposition pattern of acoustic time and neutron can be seen, the zone is gas horizon which acoustic time is high and neutron is low. The way of gasometry analysis can identify gas horizon too.Fifth, sandstone thickness of Shihezi formation reservoir is big, it widespread growth in the research area.Especially, the farewell rock including pebble is the best reservoir of the Upper Palaeozoic. Shanxi formation sandstone thickness and lothological change big, has the braided river deposition the characteristic, the reservoir is generally thin, is on the Paleozoic good reservoir. The Lower Paleozoic reservoir mainly distributes in weathering crust of Majiagou formation of Ordovician system, by the crystal dolomite primarily, corrosion pore growth. The preserve conditions of the reservoir below weathering crust chang bad, the effective reservoir is few, single-layer thickness thin, lithological character compact. The overall looked that, the reservoir of eastern part is better to the west, south is better to north.