The Research Of Chang 8 Reservoir Classification And Evaluation Of H82 Area In Longdong Oilfield.

Chang 8 reservoir is typically low permeability reservoir in Longdong H82 well area in Ordos basin. Study is needed for better understanding of the fine geological feature and reservoir classification evaluation, to make clear the potential exploration of the area, and make reference for the developed well net and technical studies in the study area.This paper is based on the Chang 8 reservoir in Longdong H82 well area. Based on the geological, rock heart, well logging and production dynamic information, formation fine divided and compared of purposes layer is carried out, also the sand top micro construction features and sand body distribution research, then carry out deposition micro phase research, reservoir heterogeneity study, "four properties" relationship research and the second logging explaination,last reservoir parameter distribution features research and reservoir classification evaluation are done.Research showed that chang 81 layer can be divided for 3 small layers: chang813, chang 812 and chang 811; chang 82 layer can also be divided for 3 small layers:chang823,chang 822 and chang 821;all constructions are simple, with high in northeast low in southwest, and develop inherited small nasal-like uplift; sand body is banded exhibition from northeast to southwest, with good ductility and plane connection, in which chang 813 is main reservoir for big sand body thickness and good oil containing. The research area is shallow delta front deposition, deposition micro phase mainly develop underwater distributary river, levee and interdistributary bay, river is from northeast to southwest, and disappear to southwest; Chang 813 and chang 822 is weak in heterogeneity compared to other layers; electric features can be used to analyze and reveal rock propery, physical property and oil contained property, physical property has good correlation with sand body thickness, deposition micro phase and heterogeneity; reservoir can be divided for four classes,classⅠand Ⅱ reservoir commonly deposited on the underwater distributary river,with good physical property, class III and IV reservoir commonly deposited on the underwater distributary river and levee,their physical properties are relatively poor; good reservoirs in the study area is located in 813 and chang 821, chang 812 and chang 823 are mainly poor/non-reservoir.The research is carried out and completed, which can greatly promote oil and gas exploration and development in the study area, and is of great theoretical and practical significance.