Papers by Author: Zhi Dong Bao

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: Abstract. Beizhong Oilfield is one of the hydrocarbon enrichment zones in Hailar Basin, whose key layer Nan1 Formation mainly develops fan delta sedimentary type. On the basis of fine stratitraphic framework, this paper firstly analysized the petrologic characteristics of fan delta, and through observing and describing of coring wells, combined with the features of logging and sesmic facies, then identified and illustrated the main sedimentary microfacies characteristics of fan delta front of Nan1 Formation in study area. Based on the above, the sedimentary model of fan delta in study area was established. Finally, the reservoir characteristics of fan delta was analysized and summarized from the study of reservoir space type, sandstone patterns and superimposed styles.