Sedimentary Simulation Experiment Of The Huangliu Formation In The Dongfang Gas Field Of Yinggehai Basin

Yinggehai Basin is a Cenozoic Rift basin in the Western continental shelf of the South China Sea,with a total area of about 11.3×10 km.The basin,situated in the border zone between the Indo-China Peninsula and the northern part of Nanhai,belongs to the extension of the Red River Fault zone in the South China Sea,and the formation of the basin is influenced by the Red River Fault strike slip and the South China Sea expansion,and its shape is a typical strike-slip pull-apart basin.The main body of Yinggehai Basin is central depression,which is composed of Yinggehai Sag,Hanoi depression and high elevation.So far,the Dongfang area of Yinggehai Basin has been proved to be close to billions of geological reserves,and high temperature and pressure gas reservoir exploration and development potential is enormous.The first high temperature and pressure gas field 13-1 gas field was successfully put into operation in May 2015,at present,5 wells have higher production capacity than ODP forecast,and their productions are better.Although the gas field can be put into production smoothly,however,there are still many problems in the implementation,such as the lack of clear understanding of the connectivity of sand body,the difficulty in developing and implementing the understanding of sedimentary microfacies,and the development of seismic information,which will hinder the further development of high temperature and pressure gas field in the future.In order to clarify the sedimentary model of the deep Huangliu Formation in the high temperature and high pressure gas field and the construction of the waterway the failure law,in order to improve the oil recovery rate as the goal,carried out a lot of work,but only by the general technical means,it is difficult to understand the complex submarine fan sedimentary facies model and sand body connectivity and overlap relationship.Therefore,it is of great theoretical and practical significance to carry out the experimental study on the sedimentary simulation of the Huangliu Formation in time.This paper is based on the Huangliu Formation Dongfang 13-1,on the basis of understanding the geological conditions of regional geology,tectonic evolution and sedimentary characteristics of the research area,and establishing the geologic model of sand body deposition process,the Dongfang 13-2 gas field is guided by the similarity theory,and the physical model is determined by means of sedimentary simulation experiment.The detailed experimental scheme is designed to reproduce the evolution process of deep water deposition by changing the parameters of flow sand and terrain boundary parameters,analyzing the main controlling factors of formation and evolution of submarine fan,analyzing the vertical superposition relation of sand body,and discussing the sedimentary facies type and sedimentary structure under experimental conditions.The experiment shows that the sea-bottom fan has the overall characteristic of the top-bottom convex,the low-lying part of the paleo-landform has the leading effect on the turbidity direction,and the turbidity head flow further erodes the low-lying area,then the sandstone filled by the turbidity body is packed,which causes the sand body thickness to change greatly.At the same time,the non turbidity developing area is also carrying on the marine mudstone deposition,and the turbidity deposition time is instantaneous and short,while the mudstone deposition time is long and continuous,because of the gravity action and the strong transformation of the bottom flow,the submarine fan sand body will fall or half collapse in the marine mudstone in a short time.Moreover,according to the sedimentary simulation experiment and the later slicing,the submarine fan mode in the Dongfang 13 area is essentially a composite of the cutting and overlapping of the channel and the leaf body.In addition,the experimental sand body slices of the submarine fan in the Dongfang 13 area show that the horizontal continuity of the sand body of the submarine fan II gas formation in the Dongfang 13 area is better than that of I gas formation,and the scale is larger.The comprehensive study holds that: there are three kinds of sand body stacking modes in the Huangliu Formation of the Dongfang 13 area,which are stacked completely,dislocation overlap and butt overlap.