First published in 2016 Indonesia Petroleum Association (IPA) Technical Symposium, this paper will illustrate how GIS Best Practices have been employed in Saka Indonesia Sesulu. From planning and execution of 550 km square 3D Seismic Survey to Rig Move monitoring activity. GIS has also helped explorationist to effectively distinct trends, find patterns and anomalies of surface and subsurface structures. GIS allows people from multi-discipline and different backgrounds to collaborate easily, and contribute to the success of Oil & Gas Exploration in South Sesulu PSC.

1. * Saka Indonesia Sesulu
19-TS-16
PROCEEDINGS, INDONESIAN PETROLEUM ASSOCIATION
2016 Technical Symposium, Indonesia Exploration: Where From - Where To
APPLICATION OF GEOGRAPHIC INFORMATION SYSTEM FOR EXPLORATION
ACTIVITIES IN SOUTH SESULU PSC
Yudi Syahnur*
ABSTRACT
PT. Saka Indonesia Sesulu (SIS) is a relatively new
national oil and gas company. Formed in 2013, SIS
acquired the operatorship of South Sesulu PSC from
Hess Indonesia in early 2014. Located in offshore
Makassar Strait, South Sesulu PSC is currently still
in Exploration period with one discovery well
namely SIS-A #1 that was drilled and tested in March
2015.
Since the PSC was signed in May 2009, Geographic
Information System (GIS) technology has been an
integral part of South Sesulu Exploration activities.
GIS is a computer-based tool for mapping and
analyzing issues that exist or events that happen on
earth. By integrating common database operations
such as query with visualization and geographic
analysis, this technology offers capabilities of
describing events, predicting outcomes, or planning
activities.
By optimizing limited amount of data, geoscientist
use GIS tool extensively to create Charge, Reservoir
and Seal Common Risk Segment (CRS) maps using
advance Spatial Analysis techniques. GIS tools was
also being utilized to validate play chance maps
against post-well results, analyzes basin activity over
time, analyze basin and play volume statistics, create
creaming curves, and estimate yet-to-find (YTF) or
undiscovered resources.
This paper will illustrate how GIS Best Practices
have been employed in Saka Indonesia Sesulu, from
planning and execution of 550 km square 3D Seismic
Survey to Rig Move monitoring activity. GIS has
also helped explorationist to effectively distinct
trends, find patterns and anomalies of surface and
subsurface structures. GIS allows people from multi-
discipline and different backgrounds to collaborate
easily, and contribute to the success of exploration in
South Sesulu PSC.
Keywords: GIS, Exploration, South Sesulu PSC.
INTRODUCTION
GIS is a multi-purpose technology which cover a
wide business area such as forestry, environment,
facilities, and land matters, mining, utilities, etc. This
technology offers a new way of doing business by
combining its maps based spatial data with tabular or
digital data with the unique visualization and
geographic analysis. The benefits offered by maps
for analysis and decision making tools are more
superior to plain data table.
As a system, GIS comprised of at least 5
components: Spatial Data, Hardware, Software,
Methods and the last but not the least, People who
use GIS to model the real world (Figure 1). Spatial
Data have been arguably the most important part of
any GIS application beside the people. No matter
how sophisticated the hardware/software or method
being used in a GIS application, it would be useless
if the Spatial Data input was inaccurate. Like any
other Information System, the principle of Garbage
In, Garbage Out is still applicable in GIS.
Spatial Data can be described as information that are
referenced to its’ geographic location of features and
boundaries on Earth, such as natural or constructed
features, oceans, etc. Conceptually, Spatial Data
represented as Points, Lines, Areas, Surfaces or
Volumes that are connected to a specific place on the
earth. It is estimated that more than 90% data and
information used in Energy sector can be categorized
as spatial data; from Block concession to Seismic
lines to Well data, they all pertaining to specific
geographic location (Syahnur, 2015).
Oil and Gas industry considered as early adaptor of
GIS technology, where application has been spanned
in every phase of Exploration and Production
activities in form of maps and databases (Figure 2).
GIS integrates common database operations such as
query and statistical analysis with the unique
visualization and geographic analysis benefits
offered by maps. These abilities distinguish GIS

2. from other information systems and positioned itself
as key enabler to every Oil and Gas companies.
GIS is a powerful tool for petroleum exploration,
particularly with regard to exploration mapping.
Such mapping is usually performed across large
geographic areas, where many data sets or map-
layers are used in the analysis of hydrocarbon
potential (Barrell, 2000).
Through the use of Symbology method,
explorationist classifies features (points, lines and
polygons) into varying sizes, thicknesses, colors, or
styles. One of the most vivid results of a GIS map is
when the symbolized data present a recognizable
trend or pattern. The explorationist then must be able
to explain this trend or pattern. In many cases, the
trend or pattern is a result of the underlying
geological processes.
Since the PSC was signed in May 2009 by previous
operator, GIS have been an integral part of South
Sesulu Exploration activities; from basin and play
assessment, planning and execution of 550 km
square 3D Seismic Survey, Acreage Relinquishment,
Drilling Site Preparation to Rig Move Monitoring
activity.
BASIN AND PLAY ASSESMENT
Play Based Exploration (PBE) approach was
extensively used for petroleum play assessment
effectively and efficiently. PBE is an evaluation
process to arrive at an understanding of the
fundamental logic of hydrocarbon plays, as a sound
technical basis for ranking and prioritizing all
exploration projects and activities (de Jager, 2014).
PBE is simply a method to build and leverage an
understanding of the basins petroleum systems and
geological plays in the company portfolio. The
benefits lie in providing better early focus for ranges
of exploration activities.
The PBE methodology is encapsulated in the
“Exploration Pyramid: Basin-Play-Prospect” (Figure
3), where the initial focus is on the basics - the
determination and description of the regional context
and the basin framework leading to an understanding
of the working petroleum system(s). Petroleum
system understanding forms the basis for the
subsequent play focus - quantifying the various
aspects of the system within each play, and using
tools such as common risk segment mapping to
highlight sweet spots within each plays. When the
plays have been recognized and where possible,
quantified, then the focus shifts again to use more
detailed geological and geophysical analysis to
define prospects within each plays, and build the
portfolio. It’s including making estimates of
volumetric, risk and uncertainty.
Geographic Information System (GIS) tools was
extensively used to create Charge, Reservoir and
Seal Common Risk Segment (CRS) maps using
advance Spatial Analysis techniques (Exprodat,
2013). GIS tools was also being deployed to validate
play chance maps against post-well results (Figure
4), analyses basin activity over time, analyze basin
and play volume statistics, create creaming curves,
and estimate yet-to-find (YTF) or undiscovered
resources.
The evaluation of South Sesulu PSC follows this
workflow and it was concluded that the main risk for
generated prospects at South Sesulu PSC was Source
(Charging), while Reservoir/Trap deemed as
moderate risk.
3D SEISMIC SURVEY
3D seismic mapping is crucial to better understand
the lead structures and analogues to adjacent
discovery fields, as well as reduce risk and
uncertainty for drilling. 3D seismic inversion and
sequence stratigraphy may also help in further
understanding of the reservoir distribution.
Previous operator conducted 3D seismic survey for a
duration of three weeks during October 2010. It’s
covered a 550 km2 area on a relatively shallow water
depth from 32 to 65 meters below MSL (Figure 5),
with shallow target around 4500 ft. The survey was
using 6 streamers with 4 km cable length. The
streamer separation is 75 m and lowered to 6 meters
below sea level. Common Mid-Point (CMP) Bin size
is 18.75 x 6 m.
GIS was used extensively to create the planning map
of South Sesulu 3D Seismic survey in order to
achieve the technical requirement as planned by
exploration geophysicist. The maps were generated
from many data sources such as DISHIDROS and
BAKOSURTANAL base maps in form of either
digital or hardcopy. Hardcopy maps were then geo-
referenced to verifying coordinate systems for East
Kalimantan area and overlay with other datasets in
single coordinate systems.
Due to extensive fishing activities in the area, Public
Affair team worked hard to socialize the seismic
program to fishermen and how it may have impacted

3. their fishing activities prior to the commencement of
seismic survey. GIS maps being used to visualize
fishing activities on and around seismic acquisition
area (Figure 6) and helped Public Affair team to
effectively settle compensation for fish traps removal
in timely manner.
The ability of GIS to integrate these data has played
a key role in reducing time in resolving some of the
issues, for example uncertainty of coordinate
systems, misplaced of location from several data
sources, exact number and location of fish traps, etc.
Increased efficiency has brought down the cost and
time of seismic survey operations. Careful planning
can result in more cost-effective acquisition and
processing, and provide sufficient quality to benefit
for advanced processing (Latef, et al. 2008).
ACREAGE RELINQUISHMENT
As part of PSC agreement, at the end of the 3rd
year
of the exploration phase, 25% of the working area
should be relinquished. Due to delays on SIS A #1
drilling (initial program was scheduled in Q1 2013),
Saka should bear penalty of another 15%
relinquishment of working area on 5th
May 2013.
Final 40% relinquishment was commenced on 5th
May 2015, at the end of 6th
year since PSC was
awarded. This final relinquishment is mandatory for
additional 4 years of “Penambahan Jangka waktu
Eksplorasi” (PJWE). The history of South Sesulu
PSC acreage is shown in Figure 7.
Relinquishment should be done as accurate as
possible, as DITJEN MIGAS required
relinquishment points to be presented in degree-
minute unit. Use of 1’x1’ grid would be very helpful
to accurately locate the points and to optimize
retained acreage. Coordinate transformation from
Geographic (Longitude, Latitude) to Projected UTM
zone 50S and vice-versa should be done with extra
cautions, so that acreage calculation result is
consistent with PSC contract document. Use of GIS
software that support on-the-fly projection
transformation is highly recommended to ensure the
spatial integrity of all relinquishment points is
uncompromised
DRILLING SITE PREPARATION
Offshore drilling site preparation requires hazard site
surveys consist of geophysical and hydrographic site
surveys surrounding the proposed well locations.
Site surveys are performed to minimize the risk of
harm to personnel and equipment, and to protect the
natural environment. The objective of any site survey
is to identify all possible obstacles and hazards from
man-made, natural and/or geological features which
may affect the operational or environmental integrity
of a proposed drilling operation, also to allow
appropriate operational practices to be put in place a
mitigation plan for any risks identified.
Saka conducted South Sesulu SIS-A site survey for
duration of ten days in August 2014. It’s covered a
12 km2
area of a relatively shallow water depth
ranges from 34 to 62 meters below MSL. The site
survey consists of analog geophysical survey (Sub
Bottom Profiler, Multi-beam Echo Sounder and Side
Scan Sonar) and digital geophysical survey also
known as 2D high resolution seismic for a total 120
km long using 600m long streamer and 48 channel
receivers (Figure 8).
Once again, GIS was used extensively to create the
planning map for South Sesulu SIS-A site survey in
order to achieve the technical requirement as planned
by exploration geophysicist. The survey design
covers area of 6 x 2 kilometer consists of 19 in- lines
with 100-meter spacing and 20 cross lines with 250-
meter spacing (Figure 9).
The survey successfully provided Saka with valuable
information regarding Seabed features around SIS-A
prospects (Figure 10), as well as the latest Shallow
and Intermediate Gas Anomalies (Figure 11).
Detailed bathymetry data also confirm the water
depth of SIS-A #1 location is more than 50 meter,
thus in-situ dumping permit would not be needed.
One of the notable information was the finding of an
active gas pipeline sit only 200 meters away from
one of the prospect location.
RIG MOVE MONITORING
For years, the monitoring of daily rig move operation
have only been conducted using list of spreadsheet
consist of locations, met ocean data, towing speed
and cumulative distance. But for SIS-A #1 rig move
operation, Saka Exploration team offering new way
to conduct daily rig move monitoring by utilizing
GIS technology. Dedicated exploration personnel
was assigned to plot rig move locations every 4 hours
in a form of map, along with met ocean data such as
ocean current direction and strength (Figure 12).
This new approach has brought more clarity to Saka
Drilling team in term of how Rig Contractor
performs its daily rig move operation. By
geographically plot rig historical locations, now Saka
Drilling team have strong justification to evaluate
planned vs actual towing route. Met ocean data

4. during rig move operation can also be tracked, so that
Drilling team personnel can easily conclude whether
it would give significant impact or not to daily rig
move operation. By applying this new technique,
Saka Drilling team can manage rig move operation
in a more effective way in term of associated time
and cost.
CONCLUTION AND RECOMMENDATION
GIS technology has been used extensively in every
phase of South Sesulu exploration activities,
culminated by SIS-A #1 gas discovery. From G&G
study to Rig Move Operations, GIS have played
significant roles to the success of South Sesulu
exploration activities.
GIS is a key enabler due to its power to integrate data
and its flexibility in allowing users to develop their
own workflows which help Saka to conduct its
business more effectively. It may not be the key
factor to the finding of a working petroleum system,
but it certainly helps to eliminate uncertainty with
regards to spatial aspect in every phase of exploration
activities.
REFERENCES
Barrell, K. A., 2000, GIS: The exploration and
exploitation tool, AAPG Computer Applications in
Geology, No. 4, p. 237–248.
De Jager, J., 2014, Play-based Exploration, Course
Material, PetroEdge Singapore.
Exprodat, 2013, Petroleum Play Assessment and
Play Based Exploration. Available at:
http://www.exprodat.com/Software/TGEA/
(accessed 15 December 2013)
Longley, I., 2013, Player: An Exploration Tool. Play-
based Exploration Introduction Material. GIS-pax.
Available at: http://www.gis-
pax.com/Pages/Player.aspx (accessed 15 December
2013)
Syahnur, Y., 2015, Spatial Data Integrity behind SIS
A #1 Wild Cat Exploration Discovery, HAGI-IAGI-
IAFMI-IATMI Joint Convention, Balikpapan.
Whitcombe, D., 2006. An Overview of Geomatics
Involvement in the Offshore Oil & Gas Industry,
Hydro Fest Presentation Material, (accessible on
http://www.ths.org.uk/documents/ths.org.uk/downlo
ads/hydrofest2006_-
_overview_of_geomatics_involvement_in_the_offs
ore_oil_&_gas_industry_-_compressed.pdf).
Zukhairi M., Ruszaidi B., 2008, Oil and Gas
Exploration in Ethiopia using GIS, Map Asia
Conference, Kuala Lumpur.

5. Figure 1 - Five components of GIS technology
Figure 2 – GIS within Oil and Gas business life-cycle (modified after Whitcombe, 2006)

6. Figure 3 - Exploration Pyramid of Basin-Play-Prospect, along with typical standard tools/software being
deployed in each PBE phase (modified after Longley, 2013).
Figure 4 – Source CRS Map of Mid Miocene Clastics Play, overlayed with Well Failure Analysis Map. Red
color showing area with High Risk, Yellow color showing area with Moderate Risk while Green
color showing area with Low Risk of Source (Charge) element.

7. Figure 5 - South Sesulu 3D Seismic Area of Interest, overlayed with DISHIDROS map of Makassar Strait
Figure 6 – Map of 3D Seismic Area overlayed with Submersible Fish Traps (Red Triangles) and removed
Ordinary Fish Traps locations (Green Dots).

8. Figure 7 - South Sesulu PSC relinquishment history 2009-2015 (Syahnur, 2015)
Figure 8 - Illustration of SIS-A Site Survey activities in 2014

9. Figure 9 - SIS-A Geophysical Site Survey Design
Figure 10 - Seabed features around SIS-A prospects

10. Figure 11 - Shallow and Intermediate Zone Gas Anomalies
Figure 12 - SIS-A #1 rig move operation monitoring