Oil production prospects in the depleted fields of the Fergana Valley
UDK: 622.276.1/.4 712.8
DOI: 10.24887/0028-2448-2019-11-108-110
Key words: the Republic of Uzbekistan, Fergana Valley, Neogene, Paleogene, Cretaceous, Jurassic, Paleozoic, depletion, pressure, mature oilfield, well logging, perforation, production, build-up
Authors: A.I. Yushmanov (VNIIneft JSC, RF, Moscow), T.S. Baranov (VNIIneft JSC, RF, Moscow), V.S. Zhuk (VNIIneft JSC, RF, Moscow), A.G. Kolyagin (Zarubezhneft JSC, RF, Moscow)
In 2019 Zarubezhneft started a project on developing mature fields in Southern part of Fergana Valley by creating a joint venture with Uzbekneftegas JSC – ANDIJANPETRO LLC. First development of the assets started in 1945 with current number of 775 drilled wells with density of 1-9 ha/well; now 90% of the well stock is abandoned; some wells are idle or awaiting abandonment. Producing wells can be characterized as highly deteriorated. At the start of the project, the primary task was to perform a quick evaluation of the assets with sparse data quality and availability. The first steps were data collection and physical inspection of subsurface equipment and field infrastructure. Data collection was complicated by a fact that initial data was dispersed between different companies and institutes on the territory of the Republic of Uzbekistan and by a fact that all the source data was in all cases a hard copy. Research Institute VNIINeft (subsidiary of Zarubazhneft Group) in cooperation with Zarubazhneft carried out extensive work including digitization and analysis of all available data. Modern data evaluation methods allowed to determine and prioritize workovers in order to increase oil production. Precise data quality control and screening has been performed to define inconsistencies in initial geological data. Infrastructure inspection has been performed during a series of field trips and required not only visual control, but also well position determination, precise technical verification of well hardware and pumps in order to update current status of each well.
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Based on the data collected, well history has been
reconstructed; data included production, design and workovers. Perophysical
evaluation of digitized well logs and local reinterpretation of available 3D
seismic data has been performed. Together with well test data and production
history, it allowed to determined missed pay zones and potential exploration
targets. As a result a field development scenario has been prepared that
indicates that production could be raised four times and that leads to a new
level of project’s economics. Collection and analysis of well data form
1950’s-1970’s is ongoing. All initial information and firstly well logs are
still being analyzed. Different probabilistic scenarios are being made for
geological features in order to estimate potential target areas, evaluate
residual reserves and resources. All this information is being arranged into a
uniform database that can definitively revitalize mature fields of Fergana
Valley.
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