Study on attribute characterization for reservoir dynamic monitoring by seismic

Abstract

Study on characterizing reservoir parameters dynamic variations by time-lapse seismic attributes is the theoretical basis for effectively distinguishing reservoir parameters variations and conductingtime-lapse seismic interpretation, and it is also a key step for time-lapse seismic application in real oil fields. Based on the rock physical model of unconsolidated sandstone, the different effects of oil saturation and effective pressure variations on seismic P-wave and S-wave velocities are calculated and analyzed. Using numerical simulation on decoupled wave equations, the responses of seismic amplitude with different offsets to reservoir oil saturation variations are analyzed, pre-stack time-lapse seismic attributes differences for oil saturation and effective pressure variations of P-P wave and P-S converted wave are calculated, and time-lapse seismic AVO (Amplitude Versus Offset) response rules of P-P wave and P-S converted wave to effective pressure and oil saturation variations are compared. The theoretical modeling study shows that it is feasible to distinguish different reservoir parameters dynamic variations by pre-stack time-lapse seismic information, including pre-stack time-lapse seismic attributes and AVO information, which has great potential in improving time-lapse seismic interpretation precision. It also shows that the time-lapse seismic response mechanism study on objective oil fields is especially important in establishing effective time-lapse seismic data process and interpretation scheme.time-lapse seismic, dynamic monitoring, rock physical model, pre-stack attribute, Amplitude Versus Offset (AVO) After the special time-lapse seismic data processing, difference analysis and computer visualization of seismic data measured at different periods in the same oil and gas field, the physical properties variations in the reservoir, such as porosity, saturation, pressure and temperature, can be described, and fluid front can be traced by the seismic responses variations with time. The reason is that the changes of reservoir fluids and physical properties during the production can cause the changes of seismic responses.Rock physics measurement in lab shows that reservoir production can cause the velocity change of the seismic wave [1,2] , which is the petrophysical basis [3] for time-lapse seismic study. It is feasible to monitor the reservoir dynamic variations on seismic difference when the time-lapse seismic difference is measurable, which has been proved by theory and real application. But time-lapse seismic difference may be caused by other reservoir physical parameters [4][5][6] , rather than oil saturation, since time-lapse seismic responses are impacted by coupled effect of effective pressure, oil saturation and temperature variations, especially during the production of water-driven reservoir, in which increasing pressure,

Prediction of Reservoir Parameters Variation Based on Time-Lapse Seismic Survey

“…Oil/gas saturation and effective pressure are two important reservoir parameters to describe the variations of reservoir during development. Acquisition of oil/gas saturation and effective pressure has important meaning on dynamical reservoir monitor [2]. Many researches have been carried out to predict reservoir parameters from conventional seismic inversion.…”