Journal of Petroleum Geology, Vol.17,
No.3, pp. 253-278, 1994
©Copyright 2000 Scientific Press,
Ltd.
KARSTIC RESERVOIRS OF THE
MID-CRETACEOUS MARDIN GROUP, SE TURKEY: Tectonic and Eustatic
Controls on their Genesis, Distribution and Preservation
J.M.L. Cater* and J.R. Gillcrist**
*Petroleum Geology Group at
P.R.I.S., University of Reading, Reading RG6 2AB.
**Lasmo International Limited, Via
Vittorio Veneto 116, 00187 Rome, Italy.
Abstract
The mid-Cretaceous Mardin Group is the main
producing reservoir interval in the oilfields of SE Turkey.
During the mid-Cretaceous, deposition of lime mudstones and
bioclastic limestones took place on a carbonate platform.
Repeated tectonic uplift occurred locally throughout this time,
during the early stages of the closure of the southern Neotethys.
The interplay of eustatic transgressions and regressions with
local tectonic uplift controlled deposition and diagenesis, the
latter including major secondary porosity development during
dolomitization and karstification. Minor shortening and uplift in
the Late Cretaceous and Palaeogene created structural traps and
may also have enhanced fracture porosity. Major thin-skinned
thrust tectonics breached many reservoirs in the late Miocene.
Surface anticlines which formed during the Miocene have attracted
most of the exploration drilling to date, but may be the sites of
the most intense breaching of the reservoirs. The distribution of
the best potential reservoirs is not necessarily linked to the
positions of Miocene anticlines.
