Physical properties of the rocks of the Tyumenskaya superdeep borehole from geophysical evidence

Citation
Oa. Esipko et al., Physical properties of the rocks of the Tyumenskaya superdeep borehole from geophysical evidence, GEOL GEOFIZ, 41(6), 2000, pp. 905-919
Citations number
19
Categorie Soggetti
Earth Sciences
Journal title
GEOLOGIYA I GEOFIZIKA
ISSN journal
00167886 → ACNP
Volume
41
Issue
6
Year of publication
2000
Pages
905 - 919
Database
ISI
SICI code
0016-7886(2000)41:6<905:PPOTRO>2.0.ZU;2-C
Abstract
Geophysical data obtained from the Tyumenskaya superdeep borehole, which ha ve first exposed the most complete section of the Jurassic and Triassic dep osits in the West-Siberian petroliferous province, are interpreted. Investigation of the regularities of depth changes in physical properties o f rocks reveals a tendency for changes in factors important for porosity an d permeability. To a depth of 3-4 km, the key role is played by factors dir ectly related to the depth and lithostatic consolidation. Most important ar e factors either favoring preservation of capacity-filtration properties (o verpressure, HC presence, and favorable sedimentation conditions) or improv ing them (factors and processes giving rise to induced - cavernose or cleft - porosity). Depth exerts virtually no effect on the capacity-filtration p roperties of rocks; therefore, reservoir rocks can be present at depths exc eeding 5 km. The obtained data allow prediction of physical properties of r ocks and the most probable reservoir types In deep deposits not drilled yet . A model is proposed for the formation of a volcanosedimentary rock mass und er irregular distribution of geostatic tension in the ranges of occurrence of elastic and plastic rocks. This distribution gives rise to zones of tens ion relief, favoring the preservation of high capacity-filtration propertie s in rocks. The model permits substantiation of test ranges and explains th e observed depth variation in physical properties and filtration-capacity p roperties of rocks.