Papers by Keyword: Distributary Channel

Abstract: Fan delta facies deposition are developed in the steep slope of faulted lake basin and have features ,such as the rapid accumulation, from near provenance, clastic coarse granularity and poor sorting. By means of core, logging, well logging and seismic data, based on the sedimentary characteristics of Nantun formation of Wuerxun depression, the conclusions are as followings: Faulted basin steep slope belts are developed fan delta depositional system with volcano facies in Wubei sub-depression of Wuerxun depression;The fan delta system are divided into plain,front and front fan delta etc,three subfacies, seven microfacies; In distributary channel microfacies, sand conglomerate, gravel sandstone, middle-grit are main lithology, low maturity, poor sorting to medium, vertical sequence, visible bottom gravel and erosion surface, large scale cross-bedding are developed, partial visible horizontal bedding; channel mouth bar microfacies relatively rudimentary, lithology with sorting relatively good powdermiddle sandstone, development of small cross-bedding, horizontal bedding.

Abstract: Based on ten well cores, seventeen hundred logging data and initial potential data, sedimentary characteristics and mode of shallow lacustrine fluvial-dominated delta of Putaohua oil layer in the east of Sanzhao depression were analyzed. It is realized that distributary channel sandbodies as sand body framework of this delta system, which is abundant, closely and narrow, and the framework of sand body is in a large number of narrow banded shape (mostly 200 ~ 300m), and can extend hundreds of kilometers of continuous, dense, overall was SW, and combines well with other types sand surface to become a better distributary channel sand body. Based on understanding of sedimentary background, developmental process, sedimentary characteristics and sedimentary facies type of Putaohua oil layer in Sanzhao depression, sedimentary mode of shallow lacustrine fluvial-dominated delta is established in the study area, and sedimentary mode of five subfacies is further divided: Delta distributary plain subfacies is mode of fluvial-dominated belt body; Transition region of front-distributary plain is mode of inshore; Inner front is mode of fluvial-dominated belt body; Transition region of inner front-outer front is mode of fluvial-dominated sheet sand; Shallow lacustrine fluvial-dominated delta outer front is mode of tide-dominated sheet sand; Also pointed out that overall shows NE –SW trending submerged distributary channel sandbodies which is abundant, closely and narrow is the main reservoir of the study area. It provides the solid geological basis for the establishment of spatial distribution pattern of reservoir; identify the causes of mainly monosandbody and further tapping the potential of oil field.