Seismic provides gap-free reservoir data over long distances, and DPV-Vp correlations are used to analyze newly discovered reservoir data using petrophysics available only from discovery wells that cover a small area compared to the prospect range. deal with oil or gas fields. The model first converts seismic data into meaningful petrophysical information around the first evaluation well and then upgrades across the grid as new well information becomes available over time.
The model was tested against well logs and seismic data from the Guafita oil field in Venezuela. The correlations between DPV, seismic p-wave velocity (Vp), and porosity (ɸ) are in close agreement between experimental and model values over the entire range of porosity.
Reservoir heterogeneity
Reservoir heterogeneity is the most challenging of the five major reservoir properties (net thickness, permeability, porosity, heterogeneity, and pore pressure gradient). This is extremely useful when determining the optimal location for expensive appraisal wells in newly discovered oil or gas fields, or when early water or gas injection is an operational priority during development. It is important.
Heterogeneity and fluid transfer rates determine oil recovery for any fluid injection project. Most importantly, heterogeneity is the only reservoir property that cannot be measured by well logs, cores, or other direct methods. It was first defined by his Dykstra-Parsons in 1950, and their model is still used as the standard heterogeneity metric in the industry.1 2 Dykstra-Parsons used permeability values established in the core at 1-foot intervals to determine its dispersion, creating the dispersion relationship in Equation 1.
Both k50 and k84.1 are obtained from a log-probability chart in which the available laboratory measurements on the core sample are ordered and graphed. DPV ranges from 0 for homogeneous or homogeneous reservoirs up to 1 for extremely heterogeneous reservoirs. Field variations often range from 0.30 to 0.60. In a recent paper, the authors developed a welllog derived DPV methodology (DPVlog) to reliably estimate his DPV from core data (OGJ, July 3, 2023, pp. 32-36).
Guaphyta field heterogeneity
Seismic petrophysics determined the heterogeneity of the Guafita oil field, including over 200 wells, pertinent core and log data, historical well production data, and 3D seismic data over the reservoir area (70 km2). Identified. This field was discovered in 1984 and is separated by faults from the Cano-Limon field in Colombia, which contains several smaller faults (Figure 1).3 4 The Sanbi Oligocene Guafita Formation constitutes the main production unit, and the formation depth is 7,500 feet. It contains four clean compacted sand packets with average 2D permeability, 25% porosity, and a total thickness of 760 feet. The specific gravity of the oil is 29° API. Thirteen wells were analyzed in the field to determine the reservoir structure.
