Time-Lapse Seismic and Engineering Data Integration to Estimate Best Time for Seismic Acquisition Data

Abstract

Abstract 4D seismic is important information to optimize well planning, interventions and drainage strategy. It provides unique information regarding the properties of the reservoir between and beyond the wells; it can be used to locate bypassed oil, to identify not drained compartments or to mitigate risks such as an unexpectedly early breakthrough of injected fluids. The integration of geophysics and engineering information increase the predictive capability of reservoir simulations, and hence has positive impacts on field management. The estimation of the best time to acquire seismic data has a major impact on reservoir management since, depending on the acquisition period, seismic may not be able to identify important variations in the reservoir dynamic properties, important changes may no longer be detected, well history matching can be able to identify properties, and it can be too late for effective action in field management. 4D seismic reservoir monitoring has no value unless it impacts operations and its utility is related to the period of seismic data acquisition. The challenge is to use effectively the available information; the integration of geophysics and engineering information must be accomplished by performing the history matching process that incorporates both production and 4D seismic data. Changes in saturation and pressure, derived from 4D seismic, can be used to improve the quality of the reservoir model allowing a better understanding of the reservoir model and fluid flow. Given the importance in defining the time for seismic data acquisition, this paper evaluates the quality improvement of a synthetic reservoir model by incorporating seismic data over different production periods and identifies characteristics that impact on the best time estimation. It also, estimates the best time to the case studied considering a practical condition. The study evaluated two cases: a posteriori (Case 1) and a priori (Case 2) analysis. In Case 1 the true model is known; a history match process was performed to 2, 4 and 6 years of production using two methods considering: (1) only production data; (2) production and seismic data. By analyzing the reservoir model quality improvement it was possible to identify the main characteristics that determine the moment to acquire seismic data. As, in practice, the earth true model is unknown, in Case 2, a process flow considering a risk analysis associated with reservoir simulation was applied to estimate the best time to acquire 4D seismic information. Analyzing the reservoir model quality improvement it was possible to identify the main characteristics that determine the best moment to acquire seismic data, to a non-mature oil reservoir with water injection production mechanism. These characteristics include: saturation and pressure error maps, production data error and breakthrough distribution within production wells.