| Autor: |
D.B. Schnapper, Per Grinde, J. P. Blanche |
| Rok vydání: |
1994 |
| Předmět: |
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| Zdroj: |
All Days. |
| DOI: |
10.2118/28876-ms |
| Popis: |
Abstract This paper shows how new techniques. using integrated seismic and reservoir modelling. have shown there is no need to drill two previously proposed additional producers on the Heimdal gas field. Older simulations had shown this to be necessary in order to recover locally trapped gas. The study emphasizes the necessity of close team work to obtain the detailed reservoir description needed for such a study. A multidisciplinary team of geologists, geophysicists and reservoir specialists performed this study to reappraise the Heimdal Field. Using seismic attributes from 3D (mainly 2D amplitude versus offset AVO) a detailed structural and seismic stratigraphic interpretation provided the geometrical basis for the field model. A heterogenetic approach (identifying potential flow barriers) to detailed geology was then applied using regional experience and detailed field data including the production characteristics. The resulting reservoir model also incorporated offset fields on common regional aquifers, to properly monitor and predict the dynamic pressure behaviour and aquifer energy in this series of connecting, Paleocene, turbiditic sands. Two repetitive seismic campaigns have been acquired since the pre-production 3D seismic survey. Mapping of the water encroachment was accomplished using advanced interpretation techniques of 2D AVO and inversion. The results have been integrated into the dynamic matching process in the reservoir simulation. Introduction The Heimdal field is located in block 25/4 in the Norwegian sector of the North Sea. The fluid in place is a gas condensate overlaying a thin oil rim of about 6 meters thickness. This Paleocene gas reservoir was discovered in 1971 and put on production in 1986. A total of 2 appraisal wells and 10 production wells have been drilled. All 10 production wells are clustered within 800 meters of the structural top. The reservoir is subject to strong aquifer influx making the water encroachment a key uncertainty with respect to ultimate reserves. The original gas in place is estimated to 64 billion sm3 with ultimately recoverable reserves of 42 billion sm3. Eight wells are presently producing from the reservoir. When drilling the production wells it became evident that the reservoir pressure had declined by about 2-3 bars since the initial exploration wells. This was due to pressure depletion of nearby fields in pressure communication through the aquifer sands. A crucial factor in the life of a gas reservoir with active water drive is the water invasion. The field life and final reserves are determined by how long you can produce before your wells are watered out. With the presence of flow barriers in the form of shale layers the water invasion can be very heterogeneous. Consequently water rise measurements are important. Four of the Heimdal development wells were drilled through the gas sand and into the aquifer to serve as observation wells for water rise monitoring. P. 89^ |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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