Papers by Author: Cong Jun Feng

Abstract: Calcite cementation is one main cause for reduction of porosity and permeability. In the case of Chang 6 Member of Jiyuan Oilfield, calcareous interbeds have been investigated for the characteristics and genetic mechanisms within delta-front Chang 6 oil reservoirs so as to reveal their spatial distribution. As shown by research, carbonate content in this area more than 10% will significantly reduce reservoir porosity and permeability, as well as its oil-bearing property. In vertical, calcareous interbeds are commonly developed at interfaces, where mudstone contacts with either top or bottom of underwater distributary channels of delta front, or within channel sand bodies. Besides, underwater levees with intercalation of sandstone and mudstone and the delta-front channel bars at the top or bottom have found calcareous interbeds. Meanwhile, calcareous interbeds in plane mostly distribute in the under-Water distributary channels and also partly underwater levees. In research area, calcite cementation predominantly formed during late diagenesis, In the acidic water for under the action of carbonate cementation, provides Ca²⁺ 、Mg²⁺ and HCO_3- etc material base，Carbonate cementation content prong to accumulating at the top or bottom of neighboring mudstone and sandstone producing “calcite top” and “calcite bottom”.

Abstract: In the case of Fourth Member of Quantou Formation (K₁q⁴) in Well X5-16 of Fuyu Oilfield, it integrates the theory of reservoir architecture and methodology for flow-unit analysis to characterize the architectural units and their permeable features in reservoirs. As the research found, point bars are very developed in low-sinuosity meandering distributary channels. Therefore, parameter modeling for reservoirs, confined by reservoir architecture is firstly constructed from empirical formulas and integrating the data from closely-spaced wells in dense pattern area. At this basis, clustering analysis with optimized reservoir parameters help demarcate the classification of flow units and further the Kriging interpolation method is introduced for interwell flow unit prediction. Besides, the study also illustrates the relationship between the lateral accretion and the flow unit. Finally, the research achievements were confirmed by successfully matching the production data, so as to predict how the remaining oil distributes, or to adjust the development plan, as well as enhance the oil recovery.