Mike Bowman introduces himself as the new Head of Discipline for Appraisal and Pre-Development at BP. He has over 24 years of experience in various geology and management roles at BP. In his new role, he will be responsible for subsurface appraisal and pre-development, and work to improve integration across the exploration to development process. Some of his key focuses will include improving multidisciplinary teamwork and integration across different functions and business units.

1. Mike Bowman
bowmanm@bp.com
+44 (0)1932 762117
i W t
Sw from
logs March 2004
Issue XIII
continues overleaf
Having just about ‘warmed the seat’ in my new job, I think
it would be useful to introduce myself to you, describe my
new role and identify some of the hot buttons and topics I
will be getting involved in during the coming months. My
name is Mike Bowman and I am a geologist by training
with a background in reservoir description and
sedimentology. During 24 years with BP I have been
involved in a wide range of roles and jobs from specialist,
technology management, exploration team leader to
development and production geologist and manager. Most
recently I have been leading the Thunder Horse Subsurface
Team through appraisal and sanction into pre First Oil
Preparation.
Last year when Howard Mayson and Jim Farnsworth
offered me the new Head of Discipline role for Appraisal
and Pre-Development, I was really excited and eager to
accept what I see as not only a great role but also a great
honour with lots of challenges. I will primarily be working
alongside my fellow subsurface H.o.D’s Peter Carragher,
Mike Smith and Paul Martin but my role will require broad
linkage and integration across other functions.
I will have two areas of responsibility. The first is for
subsurface appraisal and pre-development (up to sanction)
from a business delivery perspective; the other is a
discipline health responsibility for development and
production geoscience – in this I will be working closely
with Steve Thompson, the new Staff Network Leader.
One of my key focuses will be on helping improve
integration in its broadest form – integration across the
value chain from exploration to development, greater drive
for truly multidisciplinary working in teams without
functional silos and finally, integration across the Great
Welcome From the New
Subsurface Head of Discipline –
Some Key Messages & Focus Areas

2. R&W Base Management
Introduction
Water injection and/or waterflood
projects are currently operational in
several Pakistan (Badin) fields –
Khaskeli, Laghari, Mazari, Sakhi,
South Mazari and Tangri-Jagir.
Challenges include minimising
injection system capital and
operational cost and operating all
supporting surface injection
equipment and systems in the most
effective manner.
In this case study, the interim period
between completing an injection well
and hooking it up to the surface
injection facility was utilised to benefit
from down-hole water injection –
harnessing the high pressure water-
bearing sand to inject (cross-flow)
water into a lower pressure oil-
bearing sand (Figure1). This is known
as a dump-flood and its application in
Pakistan has delivered increased field
production at minimal cost.
Ȝ Pressure-Production
History
North Akri oil field
began production in
April 1993 from the
B-sand. The field had
produced over 80%of
the OIIP as of July
2002. The B-sand in
North Akri field is
characterised by
limited aquifer
support. Field
pressure and
production behaviour
shows that the aquifer
influx is inversely proportional to
the reservoir pressure (Figure 2).
The field was being produced at
restricted rates due to the limited
aquifer support.
Ȝ Dump-Flood Opportunity
In April 2001, Well #6 was found in
the swept zone and was selected
as the first well to initiate pressure
maintenance. However, no surface
water injection system was in-
place at that time. The B and C
sand pressures derived from
Repeat Formation Tester (RFT)
analysis were 940 and 2410 psia at
–5500’ ss respectively – indicating
1470 psi pressure difference
between the sands. In well #6
then, both the B and C sands were
perforated to establish cross-flow
of water from the C sand into B
sand – thus harnessing this
pressure difference immediately
and at low cost to start water
flooding in North Akri.
Ȝ Well Completion
The net B sand was 31 feet at an
average porosity of 12%, while the
6
Surprise and Prize in Badin Dump-Floods
March 2004 – ReM XIII
C sand had 210 feet of net sand
with average porosity of 17%. Net
pay was derived by employing
cutoffs at 40% clay and 8%
porosity. See the attached log in
Figure 2. The well was completed
with a single selective between B
and C sands with 3 1/2” tubing and
7” casing. See a typical well-
completion diagram in Figure 3.
Ȝ Results
The application of dump-flood at
North Akri field has successfully,
and at low cost, optimised field
production, resulting in a 38%
increase in oil rates.
Tangri-Jagir Case Study
Parameters from two Tangri-Jagir
wells – Tangri #9 and Jagir #4 – are
detailed in Table 1, and support the
following dump-flood assessment.
Parametric Analysis
A review of Pakistan (Badin) dump-
flood results indicates that the most
important parameters in order of their
weighted influence are:
Dump-Flood Applications
Two case studies evaluating dump-
flood performance are reviewed here.
The first case, North Akri, is
discussed in some detail – the
second, Tangri-Jagir is summarised in
Table 1.
North Akri Case Study
Ȝ Reservoir Description
The sands of interest are the
Lower Goru formations of the
Lower Cretaceous age. The
depositional environment is
shallow marine/ deltaic. The B sand
reservoir is of very good quality –
with porosity variation from
12–17% and permeability variation
from 1000 to 2000 md. The
producing oil API is 50° and GOR is
around 120 scf/bbl. Net pay varies
from 26–31 feet.
Figure 1. Dump-flood schematic.
Table 1. Reservoir parameters used in analysis of dump-flood.
Seal or shale break
Lower pressure oil layer
Higher pressure water layer
Figure 2. North Akri pressure-production history.

3. 7
Tauqeer Ehsan Rana
ranate@bp.com
+92-21-561-1194 x5039
Syed Shakil Ahsan
hasanss@bp.com
+92-51-220-6487 x1512
Mansoor Ahmad
ahmadm1@bp.com
+92-51-220-6487 x1418
Syed Sajid Hasan
hasanss@bp.com
+92-51-220-6487 x1217
March 2004 – ReM XIII
Figure 3. North Akri #6 log.
Figure 4. Typical dump-flood
completion.
Figure 5a. Effect of pressure
differential.
Figure 5b. Effect of reservoir quality.
Figure 5c. Effect of perforated
interval.
Figure 5d. Effect of vertical distance
between sands.
Ȝ Pressure Differential
This is the most important
parameter (Figure 5a). This plot
shows dump-flood rates on the
X-axis and pressure differential on
Y-axis. The highest pressure-
differential in North Akri #6
resulted in the highest dump-flood
rates.
Ȝ Sand Quality (φh)
Reservoir quality is represented
here by the product of k and h.
However, product of φ and h can
also be used to define sand quality
where the permeability
assessment is qualitative. It is
evident from Figure 5b, that B
sand quality alone has little relative
effect on resulting dump-flood
rates. More important is C sand
quality, which is best in North Akri
#6. This indicates that high
productivity aquifers can best
contribute to dump-flood success.
Ȝ Stimulation
In all the three cases, the wells
required stimulation with 15% HCl
acid and foam diversion to
establish cross-flow. Therefore it is
recognised that operational
problems such as actual surface
pumping rates, effectiveness of
diverting agent, and foam quality in
a staged acid job could impact
dump-flood results.
Ȝ Completion Method
In each of the subject wells, the B
and C sands were perforated with
a large underbalance of around
over 900 psi. However, three
different perforation techniques
were employed. Comparing Jagir
#4 and Tangri #9 – with similar
reservoir parameters and the same
stimulation recipe – Jagir #4 Tubing
Conveyed Perforation (TCP)
performed better than Tangri #9
(thru-tubing) – indicating an
advantage for TCP. It is believed
that the deeper penetration and
larger holes (TCP gun) resulted in a
larger contact area for the
stimulation fluid with formation and
ultimately better clean-up.
Ȝ Perforation Interval and Vertical
Distance Between Sands: The
effect of perforated sand footage
interval and distance between
sands is plotted in Figures 5c and
5d respectively. Figure 5c shows
that the highest perforated footage
may still result in low dump-flood
rates. This suggests careful
evaluation and design of
perforation intervals. Figure 5d
suggests improved performance
with reduced vertical distance
between sands.