Abstract: Fluvial deposits contain a large number of potential reservoirs represented by crevasse splay, but there are few separate discussions on crevasse splay. Taking QHD 32-X Oilfield in the Bohai Bay Basin as an example, the sedimentary characteristics and reservoir physical properties of crevasse splays were studied in detail in combination with core, well logging, and laboratory data. The results show that: in terms of qualitative identification, the grain size of crevasse splays is mainly fine sandstone, and silty-fine sandstone; the content of suspended loads is mostly 20%-50%; the gradation is worse; the roundness is angular to sub-angular; the lithofacies types are mainly massive bedding fine sandstone, sandy bedding fine sandstone/silty fine sandstone and horizontal bedding siltstone; the genetic sequence is mainly reverse rhythm; the thickness of single sand body is 0.2-3.0 m, and the distribution of sand bodies is lobe shaped on plane and wedge shaped on section;deep dual laterolog resistivity (Rd) values of the crevasse splays in the study area are between 1.8-7.5 Ω·m, with GR of 68-82 API; a crevasse splay that is saturated with oil or rich in oil has Rd values between 4.0-7.5 Ω·m, which can be used as a preliminary criterion for quantitative identification;the crevasse splays in the study area have average porosity of 29.26% and average permeability of 207.72 mD, belonging to high-porosity and medium-permeability reservoir, with excellent reservoir potential;however, the permeability of crevasse splay reservoirs is much lower than that of point bar and abandoned channel. In-depth study of crevasse splays is conducive to tapping potential and increasing reserves in old oil fields and prolonging the production life of depleted old wells.

Key words: fluvial facies, crevasse splay, sedimentary characteristics, lithofacies type, genetic sequence, reservoir physical properties, Bohai Bay Basin