Study On Seismic Prediction Method Of Shale Oil "Sweet Spot"

With the rapid development of the domestic economy,the demand for crude oil is increasing day by day.At present,the growth of proven reserves of conventional oil in most domestic oil-fields is relatively slow,and the reserves and production of conventional oil cannot meet the needs of energy security.It is urgent to find alternative resources for conventional oil.The study found that unconventional oil and gas reserves are abundant in china,which is a major replacement resource for conventional oil.As one of unconventional oil and gas,shale oil has become the most realistic key field of unconventional oil exploration and development.The Permian Lucaogou Formation in the Jimsar Sag of the Junggar Basin,Xinjiang,is rich in shale oil resources.A 1 billion-ton reserve scale has been discovered,and the exploration and development potential is huge.It has become an important base for oil production.Affected by the low porosity and low permeability of the "sweet spot" reservoir,the production of vertical wells is low while horizontal wells are the main development method.Due to the development of micro-amplitude structures in the area,thin longitudinally and changes rapidly laterally of the “sweet spot” reservoir and the unclear distribution characteristics of engineering "sweet spot",a series of problems appeared,such as the difficulty of reaching target in horizontal well,low drilling catching rate in quality “sweet spot” and large difference in unit price and capacity.So,it is an urgent requirement to find effective seismic prediction methods to finely describe the characteristics of shale oil structures and reservoirs to help increase the productivity of horizontal wells.In order to resolve the above technical problems and promote the efficient development of shale oil,based on the research of domestic and foreign literature,this article combined with the specific characteristics of Jimsar shale oil,focused on the implementation of microstructures,high-resolution prediction of geological “sweet spot” and quantitative characterization of engineering "sweet spots" for earthquake prediction methods.The article has achieved fruitful results as follows:(1)There are a set of combined well-seismic micro-structure implementation technology,which solves the problem that low vertical resolution or horizontal modeling of a single-method velocity model,improves the accuracy of the structural model,reduces the horizontal well targeting error,and effectively ensures the accurate targeting of horizontal wells.(2)The seismic waveform phase-controlled geostatistical simulation technology has been formed,which breaks through the limitations of low resolution or strong randomness in conventional prediction methods,realizes the quantitative characterization of geological "sweet spots",and provides a basis for the geological selection of horizontal wells.(3)The quantitative characterization technology of engineering "sweet spots" with shale oil petrophysical modeling as the core has been formed,which solved the problem of low prediction accuracy of mixed shale rock mechanics model,and realized the high-precision characterization of engineering parameters,which is a useful tool for horizontal well fracturing.The constituency provided technical support.Through the above research,a comprehensive seismic prediction method for shale oil "sweet spots" has been formed,which can realize the fine description of micro-amplitude structure,geology and engineering sweet spots,and provide a basis for comprehensive selection of shale oil horizontal wells,trajectory design,tracking and fracturing plan optimization.