Applications and pitfalls of stochastically built static model realizations on reservoir characterization and STOIIP distribution of clastic reservoirs of southern Oman oil fields

Author(s):  
Raja Mukherjee
2021 ◽  
Author(s):  
Alister Albert Suggust ◽  
Aizuddin Khalid ◽  
Mohammad Zulfiqar Usop ◽  
M Idraki M Khalil

Abstract The Balingian province is located offshore Sarawak, comprising of at least 7 oil fields with its regional geology consisting of a combination of deltaic & shoreface system. Though consisting of clastic reservoirs, the fields are highly sophisticated in terms of reservoir compartmentalization, hence uncertainties in fluid contacts, differing depletion strategies and varying production performance per well. As the regional production has gone into brownfield stage, the challenge is to determine the most suitable secondary recovery method to prolong field life. The subsurface & feasibility studies conducted produced mixed results between application of water & gas injection, giving recovery factors between 30 to 40%, and implementation so much depending on source of water & gas and cost benefit analyses. The application of IOR across Balingian province are executed in pilot mode across all fields. While the pilots are still continuing, this paper is to share the methodology, recovery factors and process of the regional study and some results from the ongoing surveillance post-execution, and the wayforward.


2021 ◽  
Author(s):  
Rustem Valiakhmetov ◽  
Andrea Murineddu ◽  
Murat Zhiyenkulov ◽  
Viktor Maliar ◽  
Viktor Bugriy ◽  
...  

Abstract The objective of this work is to describe a comprehensive approach integrating seismic data processing and sets of wireline logs for reservoir characterization of one of the tight gas plays of the Dnieper-Donets basin. This paper intends to discuss a case study from seismic data processing, integrating seismic attributes with formation properties from logs in a geocellular model for sweet spot selection and risk analysis. The workflow during the project included the following steps.Seismic data 3D processing, including 5D interpolation and PSTM migration.Interpretation of limited log data from 4 exploration and appraisal wells.Seismic interpretation and inversion.Building a static model of the field.Recommendations for drilling locations.Evaluation of the drilled well to verify input parameters of the initial model. The static model integrated all available subsurface data and used inverted seismic attributes calibrated to the available logs to constrain the property modelling. Then various deterministic and stochastic approaches were used for facies modeling and estimation of gas-in-place volume. Integrating all the available data provides insights for better understating the reservoir distribution and provided recommendations for drilling locations. Based on the combination of the geocellular model, seismic attributes and seismic inversion results, the operator drilled an exploration well. The modern set of petrophysical logs acquired in the recently drilled well enforced prior knowledge and delivered a robust picture of the tight gas reservoir. The results from the drilled well matched predicted formation properties very closely, which added confidence in the technical approach applied in this study and similar studies that followed later. It is the fork in the road moment for the Dnieper-Donetsk basin with huge tight gas potential in the region that inspires for exploration of other prospects and plays. A synergy of analytical methods with a combination of seismic processing, geomodeling, and reservoir characterization approaches allowed accurate selection of the drilling targets with minimum risk of "dry hole" that has been vindicated by successful drilling outcome in a new exploration well.


2020 ◽  
Vol 10 (8) ◽  
pp. 3179-3190
Author(s):  
Mehdi Qassamipour ◽  
Elnaz Khodapanah ◽  
Seyyed Alireza Tabatabaei-Nezhad

Abstract Reservoir connectivity has a considerable effect on reservoir characterization, plans for field developments and production forecasts. Reducing the uncertainties about the lateral and vertical extension of different pay zones is the main step in developing and managing the reservoirs. Nearly all the proposed methodologies for the verification of reservoir connectivity are limited to the study of the communication of different compartments in one field. In the presented paper, first a comprehensive procedure is proposed to study the reservoir connectivity between nearby fields. The steps in this procedure are not necessarily hierarchy, but all the considerations in each step are studied to cover all the uncertainties that affect the reservoir communication. This procedure mainly comprises the study of reservoir extension, pressure communication in the hydrocarbon column, fluid similarity, top seal efficiency and faults sealing. Then, to apply this procedure for proving the communication between nearby fields, a case study of Ilam Formation in southwest of Iran is presented. The results confirm the lateral connectivity of the three pre-explored distinctive oil fields in Ilam Formation. The established connectivity leads to an increase in the pre-estimated oil-in-place volumes. This incorporated case study demonstrates how different data including geophysics, structural and petroleum geology, production and reservoir engineering are integrated to prove the communication of Ilam reservoir between these fields. This manifested technique is a powerful road map for other cases worldwide and is extremely recommended to be performed before developing those fields that are suspicious to lateral connectivity.


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