Comparison of petrophysical rock types from core and well‐logs using post‐stack 3D seismic data: Field example from Maracaibo‐Venezuela

2008 ◽  
Author(s):  
Francisco Cheng ◽  
Kumar Ramachandran ◽  
David Contreras
2019 ◽  
Vol 10 (3) ◽  
pp. 1227-1242
Author(s):  
O. Abiola ◽  
F. O. Obasuyi

AbstractCapillary pressure is an important characteristic that indicates the zones of interaction between two-phase fluids or fluid and rock occurring in the subsurface. The analysis of transition zones (TZs) using Goda (Sam) et al.’s empirical capillary pressure from well logs and 3D seismic data in ‘Stephs’ field, Niger Delta, was carried out to remove the effect of mobile water above the oil–water contact in reservoirs in the absence of core data/information. Two reservoirs (RES B and C) were utilized for this study with net thicknesses (NTG) ranging from 194.14 to 209.08 m. Petrophysical parameters computed from well logs indicate that the reservoirs’ effective porosity ranges from 10 to 30% and the permeability ranges from 100 to > 1000 mD, which are important characteristics of good hydrocarbon bearing zone. Checkshot data were used to tie the well to the seismic section. Faults and horizons were mapped on the seismic section. Time structure maps were generated, and a velocity model was used to convert the time structure maps to its depth equivalent. A total of six faults were mapped, three of which are major growth faults (F1, F4 and F5) and cut across the study area. Reservoir properties were modelled using SIS and SGS. The capillary pressure log, curves and models generated were useful in identifying the impact of mobile water in the reservoir as they show the trend of saturating and interacting fluids. The volume of oil estimated from reservoirs B and C without taking TZ into consideration was 273 × 106 and 406 × 106 mmbbls, respectively, and was found to be higher than the volume of oil estimated from the two reservoirs while taking TZ into consideration which was 242 × 106 and 256 × 106 mmbbls, respectively. The results have indicated the presence of mobile water, which have further established that conventionally recoverable hydrocarbon (RHC) is usually overestimated; hence, TZ analysis has to be performed for enhancing RHC for cost-effective extraction and profit maximization.


2015 ◽  
Vol 3 (2) ◽  
pp. T69-T80 ◽  
Author(s):  
Nimisha Vedanti ◽  
Sanjay Surya Yerramilli ◽  
Ramesh Chandra Yerramilli ◽  
Mrinal K. Sen ◽  
Ravi Prakash Srivastava ◽  
...  

We carried out an integrated reservoir characterization to model a heavy oil reservoir called Balol located in the heavy oil belt of Mehsana in the western state of Gujarat in India. The Oil and Natural Gas Corporation of India was the field operator. The operator adopted in situ combustion process in northern part of Balol because of high-mobility contrast between oil and water. However, the performance review carried out by the operator found that oil recovery from this field was not as per prediction. Hence, serious attempts were made to interpret 3D seismic data to map the reservoir efficiently. We integrated the information derived from 3D time-lapse seismic data with the well logs provided by the operator to explain the movement of thermal front tracked using time-lapse seismic data. To model the reservoir, flow unit and electrofacies characterization was also carried out, and four to five FUs with conduits and baffles to flow were identified. Electrofacies analysis identified three major reservoir facies. These analyses also revealed that Balol reservoir was layered and heterogeneous with depth. Further, in addition to 3D seismic data, well logs and empirical equations were used to generate porosity, water saturation, and permeability models for the entire reservoir. Thus, a reservoir model with heterogeneous distribution of petrophysical properties was generated. We observed a high permeability trend in the northwest direction at injection wells, which could be governing the movement of thermal fronts in the reservoir.


2000 ◽  
Author(s):  
Mario Atencio ◽  
Victor Sanchez ◽  
Eduardo Breda ◽  
Silvana Fronza ◽  
Benito Saavedra ◽  
...  

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