Quantitative detection of fluid distribution using time‐lapse seismic

Abstract

A B S T R A C TAlthough previous seismic monitoring studies have revealed several relationships between seismic responses and changes in reservoir rock properties, the quantitative evaluation of time-lapse seismic data remains a challenge. In most cases of time-lapse seismic analysis, fluid and/or pressure changes are detected qualitatively by changes in amplitude strength, traveltime and/or Poisson's ratio.We present the steps for time-lapse seismic analysis, considering the pressure effect and the saturation scale of fluids. We then demonstrate a deterministic workflow for computing the fluid saturation in a reservoir in order to evaluate time-lapse seismic data. In this approach, we derive the physical properties of the water-saturated sandstone reservoir, based on the following inputs: V P , V S , ρ and the shale volume from seismic analysis, the average properties of sand grains, and formation-water properties. Next, by comparing the in-situ fluid-saturated properties with the 100% formation-water-saturated reservoir properties, we determine the bulk modulus and density of the in-situ fluid. Solving three simultaneous equations (relating the saturations of water, oil and gas in terms of the bulk modulus, density and the total saturation), we compute the saturation of each fluid. We use a real time-lapse seismic data set from an oilfield in the North Sea for a case study.

Structure‐coupled multiphysics imaging in geophysical sciences

“…Combining multiple physical measurements of different modalities may be a better approach. For example, there are significant uncertainties in the quantitative analysis of only time‐lapse seismic measurements over petroleum reservoirs [ Landrø , 2002; Furtney and Woods , 2006; Tsuneyama and Mavko , 2007]. Yet it is observed that fluid withdrawal from a reservoir may be associated with geomechanical deformations (especially in weak rock formations) and seismic time shifts [e.g., Minkoff et al , 2004; Hatchell and Bourne , 2005; Aarre , 2006; Rickett et al , 2007].…”

Quantification of modelled 4D response and viability of repeated seismic reservoir monitoring in J-Area Field, Central North Sea

“…When producing the hydrocarbons, there are several reservoir properties which undergo changes, such as fluid (water) saturation, pore pressure, thickness and temperature. However, the focus of this study is on the effects of changes in water saturation (Sw) and pore pressure which are dominant in most clastic reservoirs (Fanchi et al 1999;Landrø et al 2003;Tsuneyama and Mavko 2007;Ji 2017) and those expected in J-Area field. The study used two types of data sets; well data and two sets of 3D seismic data.…”

Application of combined time‐lapse seismic refraction and electrical resistivity tomography to the analysis of infiltration and dissolution processes in the epikarst of the Causse du Larzac (France)

“…Time‐lapse studies also provide a means to study geophysical parameters, by analysing their variations over time (water saturation or weathering for example). In geophysics, it can be challenging to monitor water saturation, as demonstrated by numerous publications (Stovas and Landrø ; Kowalsky, Finsterle, and Rubin ; Tsuneyama and Mavko ; Clément et al . ; Jacob et al .…”