Study On Sedimentary Facies And Reservoir Characteristics Of Yangchang Formation, Fuxian County, North Of Shanxi Province

Occurrences of oil and gas in Fuxian County can be described as existing inevery well but little production. Exploration results indicate that the sedimentaryfacies vary frequently in Yanchang formation. The reservoirs distribute complicatedlywith strong heterogeneity, bad physical characteristics and lacking of traps. As for thehydrocarbon distribution and exploration, reservoir property is one of the mostimportant facts. Therefore, searching for the lithological and stratigraphical traps withhigh reservoir quality in Mesozoic Erathem is the key direction for oil and gasexploration in the area.Via the research of geology in the past years, we have already got a basicunderstanding of the mother rock, reservoir rock, cap rock, trap, preservationconditions and characteristic in this area, but our research in some fields are stillrelatively weak, such as the distribution of the sedimentation system, thecharacteristics of oil reservoir formation, rule of oil & gas enrichment, the physicalproperty of the reservoir with low porosity and low permeability, etc. The oil & gasenrichment in Fuxian county has great relations with sedimentary facies and thedistribution of the reservoir, which is the important base of the oil & gas geologyexploration in the area. So improving the understanding of sedimentary facies andreservoir is very significant to Fuxian county in searching the new oil & gasenrichment block, deepening exploration and increasing the exploration economy andbenefit.In the discourse, we use the new theory, new method and relatively testing &analyzing means, such as the modern sedimentology, sequence stratigraphy, reservoirgeology, etc. Started from the regional geology background of the whole sedimentbasin and its ancient geology location, taking the testing & analyzing materials of core,well measurement, well drilling, outcrop section as base, accepting the relativelyregional geology materials and literature as reference, we have made systematicresearch on the sedimentary facies , sediment system and its surface distribution andrule of vertical evolvement, and processed the stratigraphical sequence classificationand correlation of target sequence. Combining the analysis of normal rock thinsection, cast thin section and single well sediment facies, so as to make a detailobservation and analysis to the rock diagenesis, which reflects the controllablerelationship between the diagenesis ,pore evolvement & physical characteristic, andanalyze the reservoir pore type, formation, distribution and its controlling factors, alsodiscover the pore evolvement and physical characteristics. Finally combining theresearch and understanding of the regional reservoir distribution, physical propertyvariation, diagenesis evolvement, pore structure, etc. generally evaluate theadvantageous facies belt and advantageous reservoir distribution, which will be agood scientific guidance of improving the oil & gas exploration.By analyzing sedimentary facies and reservoir characters of a lot of rock cores,well logging data, and outcrop sections, considering that Yanchang formationdeveloped tow relatively unattached sand sedimentary systems in the southwest andeast of Fuxian County , that's the north tip of Huangling delta sediment body and thewest tip of Fuxian County sediment body. Mesozoic reservoir entire are minor poreand throat rocks, mostly growths remnants intercrystal pore and intergranular solutionopening, diagenesis ended in later diagenetic A-B stage. The reservoir character ofYanchang formation is poor and relatively intensive heterogeneity, generally, it'sporosity and permeability are low, but the porosity and permeability of the sixthmember of Chang formation is better, which is the main reservoir of Mesozoic.Through the study of oil and gas pools, considering that there mainly developedstratigraphic-lithologic reservoirs, The distribution of oil and gas is controlled byoil-generation centers, reservoir spreading is controlled by Sedimentary microfaciesand the migration and accumulation of oil and gas is controlled by favorablereservoirs.