Sedimentary Characteristics and Architecture of Fan Delta Front Reservoir Based on Dense Well Pattern in Oilfield, China
J. Wang and X.M. ZHOU
Event name: IOR 2017 - 19th European Symposium on Improved Oil Recovery
Session: Poster Introductions 3
Publication date: 24 April 2017
Info: Extended abstract, PDF ( 3.76Mb )
Price: € 20
The study focus on a Paleogene sandstone reservoir in the northeastern China deposited on a fan delta front, which started to produce since 1986. Through long term of steam huff-puff, the average reservoir pressure declines from 9.75Mpa to 2Mpa, the water cut increases to 90%. Therefore, a steam driving pilot with 417 wells is built, and the detailed sedimentary analysis and reservoir architecture characterization is urgently needed to better understand the distribution and connectivity of reservoir. The study is based on the analysis of 6 core data, 417 well logging data and several surveillance data, such as injection profile and tracer. The reservoir architecture in single well, plane and profile of main producing layers is depicted, the architecture modes is established with the analysis of connectivity and forming environment, the scale of different architecture elements is summarized, and the effect of architecture on reservoir performance is analyzed by using surveillance data for further development adjustment proposal. There are 14 lithofacies identified in the study area, which can be classified into five architecture elements: underwater distributary channel, mouth bar, underwater distributary inter-channel sand, underwater distributary inter-channel mud and sheet sand. Three types of lateral architecture modes, five types of vertical architecture modes, and three types of plane combination modes of architecture elements are established, with detailed discussion of pattern, cross section, plane distribution, genetic mechanism and connectivity. The scale of distributary channel and mouth bar in different architecture modes is summarized and compared. Finally, further development adjustment plan is proposed according to the effect of architecture on reservoir performance, such as the producing layer with isolated banding distributary channels is suggested to perform stratified gas injection, the injection and producing well should be placed in layers with good connectivity, like sheet-shaped distributary channels etc. The study provides a comprehensive case study for geologists and engineers to better understand the sedimentary characteristics and architecture of fan delta front reservoir, which help to provide fine-scaled geological model and adjust development plan for improving recovery.