Reservoir Description And Geological Modeling In Development Phase

Nowadays, because of the problems, such as shortage of petroleum reserve, high degree and great difficulty of exploration, more rational, persistent and effective development of oilfield are required in China. As the important methods in oilfield development, reservoir description and stochastic modeling become research hotspots in insuring the durative and steady development. The Block-B19 in Baolige oilfield, which is in development phase, is used as an example in this paper. Focusing on rapid facies change, difficult sublayer correlation, broad scale properties and serious reservoir heterogeneity in Block-B19, the paper adopts several advanced geologic theories and technologies, such as reservoir sedimentology, high-resolution sequence stratigraphy, facies-controlled stochastic modeling, to describe the reservoir characteristics and to build up the geological model of oil set II, the fourth member of Aershan group in Lower Cretaceous. Through the research mentioned above, the following results are achieved: (1) Oil set II is divided into 5 middle-term stratigraphic cycles. During these cycles, A/S (Accommodation /Sedimentary rate) has gone through the process from decrease to increase, and this variation dominates not only the distribution of micro-facies, but also stacking patterns and evolution character of sand. Sand presents stack and connectivity in the middle and isolation in the top and bottom .The third middle-term stratigraphic cycle has thicker sand than the others. According to the variation of base-level movement and A/S value, middle-term cycles are classified into five types of evolvement phases, i.e. slowly rising, rapidly rising, transition of rising to decreasing, slowly decreasing and rapid decreasing. Stacking patterns of short-term cycle and their sedimentary genetic analysis are summarized in this paper. (2) From depositional view, oil set II is featured by close provenance, coarse grain, and short water system. The studied area lies on one lobe of fan-delta front, and its provenance is from the NNE or NEE (30～85o). On the basis of stencil-plate of logging facies and pattern of sand correlation, the patterns of micro-facies distribution are summarized. The underwater distributary channels sand is the major type of sand. (3) The studied reservoir has moderate porosity and permeability and with low component maturity and textural maturity. The heterogeneities of reservoir are moderate in...