Research On Reservoir Characteristics Of Chang-6 Oil Reservoir Set In Hujianshan Area In Ordos Basin

Hujianshan area is located in the center of Ordos Basin. The Chang-6 oil reservoir set of Yanchang Formation is principally producing formations in the study area. The thickness of single sand body varies greatly with bad physical property and obvious anisotropies, and complex relationship between oil and water is the typical characteristics of this layer. This paper taked Chang-6 oil reservoir set as main analysis object, combined sedimentary petrology, reservoir sedimentology, sequence stratigraphy, logging geology together. Based on the researching of sequence stratigraphy, sedimentary system and sand body distribution features, to systematic research reservoir character characteristics and reservoir control factors. This paper has been predicted the favorable areas.Based on the above researching, this paper has been gained research results and new knowledge:1. Based on the analyse of outcrop profile, drilling profile, core observation and logging data, confirming this area pertained to meandering river delta sedimentary system and lake sedimentary system .2. From the sand body distribution features of Chang-6 oil reservoir set in the study area, distribution of sedimentary microfacies affects the distribution of sand body. The direction of sand body mainly present bands, which is from northeast to southwest, and become repeatedly.3. Combined with the cores, chip analysis and other test material, this paper points out that the arkose and lithic arkose as the main sandstone types in the study area, with low compositional maturity and textural maturity. The interstitial material mainly include clay mineral and carbonate cement. The reservoir diagenesis mainly includes compaction, cementation and dissolution. Reservoirs mostly low porosity and density - nearly density from core property analysis results. By the research on the pore texture of rock, the relationship between porosity and permeability of Chang-6 oil reservoir set in Ordos Basin in the study area, it is considered that much higher heterogeneity exists at the innerbed and the plane.4. By analyzing the cores and the reservoir physical properties, it comes to conclusion that sedimentary facies is the main factors controlling the researvior distribution. And next is diagenesis .Sedimentary facies in the macro control petrophysical property is good or bad. Favorable facies belt is mainly developed at the sandstones in distributary channel of delta plain, underwater distributary channel of delta front and debouch bar of delta front. It comes to the conclusion that the most destructive diagenesis includes compaction and cementation, and the favorable diagenesis includes dissolution and chlorite cementation which makes the reservoir has better physical properties5. Combined with the sedimentary facies, sand body thickness, reservoir physical properties, reservoir heterogeneitya and water-oil relations research achievements, predicting the favorable area for each section of Chang-6 oil reservoir set. And it locates in center and the southwest of the study area.