生物扰动对储层的影响

zhazi_hou

AAPG Bulletin, v. 94, no. 7 (July 2010), pp. 1059–1078

Bioturbation influence on reservoir quality: A case study from the Cretaceous Ben Nevis Formation, Jeanne d’Arc Basin, offshore Newfoundland, Canada

Nicola S. Tonkin, Duncan McIlroy, Rudi Meyer, and Allison Moore-Turpin

ABSTRACT
The delineation Ben Nevis L-55 well, located in the Hebron-
Ben Nevis field, offshore Newfoundland, targeted the Cretaceous
BenNevis Formation in the petroleum-rich Jeanne d’Arc
Basin. This case study focuses on the bioturbated net-pay horizons
and assesses the importance of animal-sediment interactions
in controlling the porosity and permeability of sandstone
reservoir intervals. Our data reveal that bioturbation can either
reduce permeability and porosity by as much as approximately
33% or enhance it by up to 600%, dependent on burrow type
and behavior of the trace-making organism.
The net-pay interval in the cored interval of BenNevis L-55
is characterized by Ophiomorpha-dominated ichnofabrics. The
action of bioturbators can be classified in terms of sediment
mixing, sediment cleaning, sediment packing, and pipe-workbuilding
strategies. Bioturbation has the potential to (1) increase
isotropy or uniformity of grain size by destroying sedimentary
laminae through burrow homogenization, or (2) decrease isotropy
by selectively sorting grains into burrow lining and fill by
grain size, and through creation of open-burrow systems filled
with later sediments of differing character to the host sediment.
The petrophysical characteristics of the reservoir facies
are highly dependent on trace fossil morphology, presence or
absence of burrow linings, nature of burrow fills, burrow size,
and bioturbation intensity. Mudstone-rich facies and ichnofabrics
containing mudstone-filled and/or lined burrows (e.g.,
Ophiomorpha and clusters of Chondrites) have the net effect
of permeability reduction. In contrast, permeability enhancement
is documented from muddy sandstone facies with clean
sand-filled burrows (e.g., Thalassinoides) and clean sandstones
with burrow-mottled or diffuse to massive textures.

zhazi_hou

第一帖，学习使用论坛。

sunpetrokook666

后面跟上。。。。。。

zhazi_hou

对海陆过度相很重要，尤其是shore face

guo0

谢谢分享！！！