Downdip-Oil Potential for an Onshore Abu Dhabi Petroleum System
- Robert J. Pottorf (ExxonMobil Upstream Research Co.) | Kirsten L. Hussenoeder (ExxonMobil Upstream Research Co.) | Kenneth Petersen (ExxonMobil Upstream Research Co.) | Hsin-Yi Tseng (ExxonMobil Upstream Research Co.) | Cara L. Davis (ExxonMobil Upstream Research Co.) | Mark Richardson (ExxonMobil Exploration Company) | Sarah Pietraszek-Mattner (ExxonMobil Exploration Company) | David W. Moore (ExxonMobil Production Co.) | Abdelfatah F. El Agrab (Abu Dhabi Co. Onshore Oil Opn.) | Ahmed A. Khouri (Abu Dhabi Co. Onshore Oil Opn.)
- Document ID
- Society of Petroleum Engineers
- SPE Reservoir Evaluation & Engineering
- Publication Date
- April 2008
- Document Type
- Journal Paper
- 395 - 403
- 2008. Society of Petroleum Engineers
- 1.6 Drilling Operations, 4.6 Natural Gas, 2.2.2 Perforating, 4.3.4 Scale, 5.8.7 Carbonate Reservoir, 4.1.2 Separation and Treating, 4.1.5 Processing Equipment, 5.2 Reservoir Fluid Dynamics, 4.3.3 Aspaltenes, 5.2.1 Phase Behavior and PVT Measurements, 5.6.1 Open hole/cased hole log analysis, 1.6.9 Coring, Fishing, 5.1 Reservoir Characterisation, 5.1.1 Exploration, Development, Structural Geology
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A combination of fluid-inclusion and geochemical analyses was conducted on rocks and reservoir fluids to develop an improved understanding of downdip-oil potential in a mature exploration play, onshore Abu Dhabi, UAE. Exploration for oil in the region is complicated by low-permeability carbonate reservoirs, poor seismic imaging, and complex hydrocarbon-maturation and -migration histories. In addition, a broad range of fluid properties, including gas, condensate, and high-°API oil, makes evaluation of the reservoir fluid phase difficult.
In this challenging environment, geochemical and fluid-inclusion techniques are effective tools for identifying downdip oil potential from gas-cap fluids and reservoir-rock samples. Fluid-inclusion data are used to develop a hydrocarbon-emplacement history, which constrains the distribution of fluids throughout the exploration area. In some areas, undersaturated gas inclusions trapped at present-day temperatures suggest a low chance for downdip oil. Conversely, other structures contain oil inclusions that have been displaced recently by saturated gas, suggesting good potential for downdip oil. Geochemical analyses of recovered fluids were used independently to predict the likelihood of downdip oil. These combined techniques were placed in a geologic framework to regionally risk the potential for downdip oil throughout the exploration area. This framework enables improved resource evaluation and prioritization of exploration efforts in areas of the play where a high probability of downdip oil exists.
Fields from an onshore Abu Dhabi exploration trend currently produce both oil and gas from shallower reservoirs and primarily produce gas from deeper reservoirs. The objective of this study is to more accurately define deeper oil potential throughout the exploration play in fields in onshore Abu Dhabi. To do this, we use geochemical and fluid-inclusion techniques to determine present-day fluid distributions, evaluate downdip-oil potential, and examine the controls on fluid-type distribution in the deeper reservoirs.
A suite of samples, including cuttings, cores, oils, and condensates, was used to develop a model for downdip-oil potential for three fields (A, B, and C) in the study area. Geochemical methods were used to establish oil-generation potential by determining source facies and thermal maturity of the reservoired hydrocarbons. Fluid-inclusion technologies were used to determine paleofluid and present-day fluid types in each reservoir, to develop a hydrocarbon-emplacement history, to evaluate controls on fluid distribution, such as intraformational seals, and to infer the likelihood of downdip oil (Fig. 1).
|File Size||3 MB||Number of Pages||9|
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