Exploring Methods And Their Application For Lithologic Reservoir

Subtle reservoir exploration becomes more and more important with the improvement of exploration and has been even leading fields in some basins. In the process of exploring subtle reservoir, many advanced theories and technologies came forth and formed lots of specific applied technologies, for instance, sequence stratigraphics studies, reservoir prediction technologies, new hydrocarbon detection technologies. Yet in many cases, we just use a certain technology individually and hope to solve complicated geologic problems instead of combination of kinds of advanced technologies. For that, a series of exploring technologies for lithologic reservoirs of lenticular sand and updip pinching sand is introduced taking a case study of subtle reservoir exploration in Banghu area of Qianjiang depression in Jianghan Basin as an example.Different levels of sequence stratigraphic units on sections should be divided firstly, and then at the control of isotime strata framework, favorable areas with good developed Uthologic traps can be dope out after microfacies recognition based on log data, core analysis results, seismic properties and inversion results.However, this research just to find out regional geologic rules still is not enough to predict drilling targets. To forecast specific positions of subtle traps , study units need to be subdivided on profiles, individual sand bodies that can be identified by seismic need to be marked off, seismic inversion with log restriction need to be done, space distributions of sand formations and individual sand bodies need to be traced on seismic inversion data sets, and. Finally, subtle reservoirs are delimited count on combination of these results with structural backgrounds.To confirm reUability of predicted Uthologic traps, forward modeling seismic wave shape and researching various shapes respond to various thickness of sand formations or individual sands can be done to understand geologic implications of variations of lithologic information indicated by different seismic attributes (wave shape characteristics). Based on that, attributes impetus on plane is studied with visual seismic 3-D and then Uthologic pinch positions are determined.To predict subtle trap effectuaUty and decide optimal drilUng spots, hydrocarbon is detected with seismic data. Based upon known weUs, kinds of seismic attributes are caUbrated by well logging formation, non-linear reflection relationship is build up between different associations of sensitive seismic attributes and strata bearing hydrocarbon, and quality of subtle traps with hydrocarbon is predicted with attribute plane variations.A updip pinching sand pool and a lenticular sand pool were found out by the writer and achieved efficient results. The advantages and practicabiUties of above methods and technologies embodied the processes of good combination and integration of geology, geophysical prospecting, well logging, and innovation and advance of every individual technology.Exploring technologies for subtle reservoirs are developing and there are stillmany weakness with it. However, the progress of well logging and seismic technologies will push on the development of exploring technologies of subtle reservoirs and therefore some abnormal methods before will gradually become normal.