IPTC 2007: International Petroleum Technology Conference

An experimental investigation on oil-gas two-phase flow
through a straight horizontal plexiglas pipe within 40mm inner
diameter was conducted. The superficial velocity ranges of oil
and air were 0.05-0.612m/s and 0.024-50.64m/s, respectively.
The atmospheric temperature condition was maintained
throughout the experiments.The frictional pressure drop
multiplier of two-phase flow was expressed using the
Lockhart-Martinelli parameter correlation in accordance with
typical flow pattern, but the modification factor C in the
correlations was defined afresh according to flow conditions.
New predict correlations for pressure gradient in accordance
with typical flow patterns were proposed and the mechanisms
of pressure drop production were analyzed for each flow
patterns. The proposed models give a good agreement with the
experimental data.

Geleki Oil & Gas Field that covers an area of about 25
sq. km. was discovered in 1968. The main hydrocarbon
bearing formations are Tipam Sandstone of Miocene
age, Barail of Oligocene age and Kopili of Eocene age
containing all together of 35 sand layers (Fig-1). As on
01.07.2007, the field has OIIP 127 MMt in PD category
and Ultimate Reserves of 32 MMt in PDD categories.
The field has so far produced about 12.60 MMt of oil.

Despite the capital intensive nature of drilling operations,
drilling analysis is not routinely practiced as it should be. This
is understandable since drilling engineers are principally
rewarded for well planning and well construction. Therefore,
the need to encourage best practices and continuous learning is
a key to drilling improvement. Otherwise, the history will
repeat itself “If you always do what you have always done,
you will always get what you have always got”.

Non renewable groundwater resources in some dry areas are
the unique source of water for all activities and sectors and
therefore constitute strategic reserves for more than ever with
the expected water shortage in the near future.
Contamination due to the infiltration of pollutants coming
from oil and gas industries is one of the major risks that are
jeopardizing these valuable resources.

Even though production data have direct responses of reservoir
heterogeneity and connectivity, they are rarely incorporated into
reservoir modeling workflow among the geological community. In
this paper, a designed simulation method is proposed to mitigate
reservoir connectivity uncertainty. This proposed method is more
accurate and efficient by integrating production data with reasonable
computational cost. This method, applied on a North Africa shallow
marine reservoir, includes following four steps.

Most oilfields in South Oman comprise mature, heavy oil
reservoirs with sub-hydrostatic pressures. Wells need be put
on artificial lift since the beginning and different artificial lift
methods have been deployed. Rod driven beam pump is one of
the common artificial lift methods used and currently more
than 1000 beam pumped wells are in operation contributing to
about 30% of production from south Oman fields. These
oilfields, in general, are geologically very complex and
extremely heterogeneous due to the presence of large number
of faults and fractures.

Well logging programs are usually designed to measure
petrophysical properties within the reservoir and the
immediate surrounding formations. Rarely, if ever, is much of
the overburden logged. As more sophisticated surfacemeasured
geophysical methods are used, properties of the
overburden are becoming more important (fig. 1). One method
that is becoming more prevalent, 4C OBC seismic, can benefit
from logging formations from surface continuously down to
the reservoir. In preparation for the processing and
interpretation of a major acquisition of 4C surface seismic run
to illuminate a carbonate reservoir within Idd El Shargi North
Dome field located offshore Qatar (fig. 2), a specialized
logging program was devised and acquired on a well in the
field to obtain formation elastic properties of compressional
and shear velocity, including HTI anisotropy information,
continuously from the sea floor down to the reservoir.

Some naturally fractured reservoirs can exhibit linear flow in
the beginning as if it were hydraulically fractured. The linear
flow may have been imparted as a result of limited
connectivity in the well’s drainage area, thus creating
formation anisotropy and/or heterogeneity. The primary
purpose of this study is to develop a welltest interpretation
method to quantify anisotropy in naturally fractured
reservoirs. The method, which is based on an elliptical flow
model, is extended to hydraulic fractures with infinite
conductivity.

Production logging low flow rate wells is difficult because
mechanical spinners have a small dynamic range in slow
moving fluids. Low flow rates in horizontal wells means the
fluid holdups in the stratified flow are very sensitive to the
wellbore inclination, and the high water cut means a small
proportion of the flowing liquid will be oil. At what point do
these compounding affects limit the ability of current
technology to measure low oil flows?