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VSAT Applications for Oil/Gas Drilling
and Seismic Explorations A.N. Al-Baharna Communications Engineering and Technical Support Department Satellite Engineering Group SAUDI ARAMCO West Park #3121, Dhahran 31311, Saudi Arabia Email:baharnan@aramco.com.sa Abstract This paper will explore the
advantages of Satellite-based communications particularly VSAT for the Oil and Gas Industry. Within
the energy industry, there are numerous applications for VSAT. The shared common factor for all of
these applications is cost effectiveness and flexibility. The Oil and Gas operations today
are competing aggressively with time. The less time it takes to explore and drill for oil
and gas reservoirs the more savings for the company. VSAT technology has helped leverage the
oil and gas industry by providing a common medium to transport voice, video and data from
anywhere to anywhere. Hence, VSAT
provides a scalable, cost-effective and flexible network assisting the Oil and Gas
Industry daily operation needs. Keywords: VSAT, Satellite, Leverage, Single medium,
Cost-effectiveness 1 Introduction As Oil exploration, drilling and
production is expanding throughout the world, Oil and Gas companies are seeking new
information transport solutions to enhance efficiencies and lower costs [2]. In addition
to the traditional pipelines that stretch thousands of miles across the ocean floors and
the continental terrains, Oil and Gas companies are continuously turning to Communication
Pipelines that reach thousands of miles up in the sky and through which flow billions of
bits and bytes of communications traffic. Current and future needs exceed
simple voice connectivity. Modern exploration and drilling operations generate significant
volumes of complex data and telemetry that need to be transmitted in a timely fashion to
decision makers at the home office [2]. Since wired fiber infrastructure is not available
in most frontiers the communications infrastructure must be wireless or satellite-based.
VSAT stands for “Very Small
Aperture Terminal and refers to a ground station or earth terminal (typically between
1-2.4m), which is part of a network providing communication services via satellite.
I- VSAT Components As shown in Figure 1, the VSAT system is composed of an Outdoor
unit and Indoor unit. Outdoor Unit (ODU): This is
mainly the RF components of the VSAT
system which can be considered as the interface to the space segment. The Outdoor unit is
comprised of a parabolic antenna, Low Noise Block (LNB) for amplifying the received
signal, Power Amplifier (PA) to transmit the signal. Indoor Unit (IDU): The indoor
unit is typically the satellite modem which provides the modulation, demodulation,
multiplexing, de-multiplexing and synchronization with the rest of the network and
supports the user interfaces. This box is usually about the size of a domestic video
recorder. Figure1. VSAT Components.
The VSAT equipment operates in several
frequencies. ( see table below)
Table 1. VSAT Frequencies. Naturally, radio signals are
affected by the medium they pass through if it is not a perfect vacuum. The wavelength of
the radio signal and the characteristics of the particles in the medium will determine the
level of interaction between the medium and the signal [4]. For example, the Ku-band
signal is more prone to signal losses during rain. This loss is due to the high frequency
characteristic of the Ku-Band ( 12-14 GHz). Whereas a C-band signal (4-6 GHz) wonÂ’t
get much affected during rain. The choice of the VSAT frequency is based on the
applications and the environment natures of the operating site. Ku-band and Ka-Band
frequencies can get higher data-rates transmitted and received through small diameter
dishes, however, if they are installed in a country were there are heavy rains, the
performance of the link will not be optimum. On the other hand the lower frequency of C
band achieves less signal losses during rain, and requires an antenna diameter of at least
2.4 m to support high data rate applications. So generally there are trade-offs on how the
user wants to design the network and what applications he is looking for. The Ka-Band frequency is a very promising frequency. The 25-30 GHz frequency range will assist in utilizing even smaller dish sizes than the Ku-band for high-speed applications ( typically less than 1m for speeds up-to 2mb/s or even higher sometimes). Commercial satellites with Ka-band frequencies are already being designed and ready to be launched. The Spaceway Satellite (owned by Hughes Networks) to be in orbit by 2003 is one of them.
III- VSAT Configurations VSAT systems may be operated in a STAR
configuration or a MESH configuration. STAR: This architecture is
referred to as a STAR configuration, since all the traffic from the remote sites have to
access a centralized Hub to access the required information [1]. Moreover, if any two
remotes require communications between them they need to access the Hub first. MESH: This architecture is
referred to as a MESH configuration, since any remote site can communicate directly with
any other VSAT [1]. In other words,
the remote sites donÂ’t require a Hub to communicate to each other. Alternatively a VSAT network can have a hybrid network of
STAR and MESH by mixing both architectures within one VSAT network. IV- VSAT Access Technologies There are two main access
technologies in VSAT systems. The
first is the Frequency Division Multiple Access (FDMA) and the second is Time Division
Multiple Access (TDMA). FDMA: In FDMA, a given sub-band of a transponder
is allocated to a certain user. Furthermore, each VSAT station is assigned a single
frequency. This method is called Single Channel Per Carrier (SCPC). The SCPC access scheme is defined when a frequency is allocated to
a VSAT station to communicate with a
central Hub or another remote station. The frequency is not shared but is dedicated for
that remote station all the time. TDMA: On the other hand, TDMA
technology is the opposite of SCPC. The frequency is shared among several remote sites and
is assigned on demand. Whenever there is a requirement to transmit information, the
frequency is allocated to that station. Once that station is finished the frequency is
released for another station to use it. 3 VSAT Applications
I- Drilling The frequent moves of the Rigs
cause chaos for operators struggling to schedule and coordinate the mobilization of major
structures, personnel and supplies while maintaining safe and profitable operations. VSAT satellite networks are designed to provide connectivity immediately upon arrival at a new location. Drilling operations typically require:
All of those applications are supported reliably by the VSAT terminal. VSAT allows for the real-time
transmission of drilling data vital to the drilling operations. The rigs
managers/supervisors can keep track of the activities of various rigs from which they can
analyse data immediately to recommend changes, identify potential operational and safety
hazards or even request further information on the drilled Oil/Gas well [3]. Furthermore, the immediate
connectivity of VSAT will save a lot
of time and money on the drilling operation. Typically the operation of the Rig costs
$20,000/day for an onshore rig and $50,000/day for the off-shore Rig. By utilizing LWD
(Logging While Drilling) mechanism in conjunction with the VSAT technology the Rigs can expedite the
drilling operation and achieve more productivity of the reservoirs. Hence, the shorter the
drill period the more money is saved for the company. In addition to that, the reliable
communications of VSAT makes it more
adequate for the safety regulations of the drilling operations. Figure 2. VSAT application for Drilling. II-
SCADA (Supervisory Control and Data Acquisition) For Oil and Gas Wells Oil and Gas companies require monitoring of their pipelines and wells to ensure the safety operation of these wells and pipelines and also to anticipate abnormal conditions that might lead to disasters. These metering and control points are typically in remote areas with limited access to power and any communications infrastructure. This is one of the challenges that faces the energy industry today, especially Oil and Gas companies that have thousands of oil and gas wells scattered in remote areas [3]. This challenge is overcome today
by several techniques. One of those techniques is using hybrid technology of Satellite and
terrestrial radio (Figure. 3). Because each well needs an average data rate of 9.6 Kb/s,
installing a VSAT terminal at each
well is not cost-effective at the time being ( Once the price of the VSAT terminals drops, the installation of
a VSAT terminal at each well can be
revisited). Therefore, oil and gas wells are fixed with radio communications to
communicate with a single base station (a single base station can take on 150-200 nodes)
which is interfaced with a VSAT
terminal that will transfer the collected data from all the wells at the base station to
the corporate headquarters. By utilizing this technique the VSAT terminal is advantageous because the
base-station does not require multiple repeater hops or thousands of fiber/copper reels
and regenerators to replicate the data to the corporate headquarters. Also, by providing
such a solution means that the data center resides within the corporate premises. This
offers more inherent security.
Figure 3. VSAT application for SCADA. III- Seismic
Explorations Onshore As the petroleum industry moves
to explore new prospects that are more remote, the need for an intelligent, flexible and
high-performance communications infrastructure to support remote operations has become
more critical. The oil industry spends between $60 and $65 billion each year on oil
exploration [2]. The oil industry does not typically conduct oil
exploration and production activities near population centers. As a result the best
solution is to deploy satellite services. For onshore explorations, the
seismic crews need to communicate with their superiors at the headquarters to update
drawings, send morning reports and ship seismic data for analysis. Today the existing VSAT terminals in the market can ship the
large seismic files that reach up to gigabytes. However, it depends on the access scheme
to the satellite system. On of the techniques utilized today is shipping the terabytes
data through high speed terminals that communicate with on-board processing satellites
that relay the data to the headquarters. This technique is more popular with the offshore
seismic explorations. Offshore: Similar to the onshore
applications, the offshore crews require to communicate with their superiors and also to
transfer the large seismic files. The most challenging of the offshore data transfer
challenges involves moving seismic data from moving vessels while they are on the
prospective exploration site. To support such explorations, NASA has a fleet of seven
satellites called the Tracking and Data Relay Satellites (TDRS) in geo-synchronous orbit
with worldwide up-link coverage. The data is received at the NASA receiving station at
White Sands Center. These satellites are being
utilized by the SeismicStar system. The SeismicStar system is a complete turnkey service
consisting of all equipment, maintenance , licenses, fiber connectivity, training to
deliver raw uncompressed marine 3-D seismic data to a land processing center located
anywhere in the world. The SeismicStar system consists
of a shipboard satellite receiving station and transmission elements, capable of
transmitting data at 311 Mb/s [5]. A dayÂ’s 3-D seismic production of 150 Gigabytes
of data can be transmitted and received in the U.S in 81 minutes [5]. Onboard components
include a motion stabilized 2.4 m antenna with radome, two 155 Mb/s modems, file and
communication servers, GPS, satellite phone, 1 Terabyte of RAID storage , associated
electronics and administrative software. Because of the unique design and
the very large bandwidth of the NASA TDRS satellites, the SeismicStar transmission is by
far the fastest commercial satellite capability in the world. The point to point
SeismicStar is over 3000 times faster than Inmarsat, which is the only other satellite
constellation with ocean coverage [5]. Figure 4. SeismicStar System. Early delivery of seismic data at
the client processing center can add substantial value to the client oil company. Value to
the oil company is derived mainly from the early delivery of the final displays , which
can cause earlier generation of drillable prospects and earlier realization of cash flows
associated with hydrocarbons production. These cash flows can be reinvested earlier, and
due to the time value of money, can add $2 to $4 million to an oil companyÂ’s value
for each 3-D survey delivered early [5].
Figure
5. NASA Tracking and Data Relay Satellite (TDRS)
The VSAT technology is one that has truly
helped to improve the performance of the Oil and Gas Industry. Satellite communications
(through VSAT) has helped leverage and
enhance the Oil and Gas daily operation needs. Whether the operations are on-shore or
off-shore, satellite communications has erased all border lines by providing a single
wireless infrastructure to transmit voice, video and data via a single medium over any
distance. This technology can take on the challenges that are facing the Exploration and
Drilling managers/engineers today by supporting various services to manage and optimize
network availability. Satellite Communications can
maximize return on investment for the Oil and Gas industry by enabling the drilling and
seismic exploration crews achieve greater efficiencies by utilizing a single
infrastructure to transport voice, video and data. Acknowledgement The author acknowledges the
support of M.I. Al-Dhamen General Supervisor of Communications and Infrastructure
Engineering Division, Majid J.Al-Majid Supervisor Telephone and Switching Group, Abdulaziz
Al-Ismail IT Strategic Planner, Rami Al-Mushcab Supervisor Transmission Engineering Group
and Hussain Al-Jarrash Supervisor Satellite Engineering Group. References [1] Maral, G. ‘VSAT Networks’ John Wiley & Sons, 1995 (ISBN 0 471 95302 4) [2] Space Business International , Journal 1999 Global VSAT Forum [3] Space Business International, Journal 2000 Global VSAT Forum [4] Evans B.G. (ed). ‘ Satellite Communication Systems’ (Peter Perigrinus), 2nd edn 1991, 3rd edn 1999 ISBN 0 85296 899 X [5] William K. Aylor, SpaceData Int'l LLC, Offshore, August 2001 Biography Ahmed Al-Baharna
is a satellite communications engineer currently working on the Saudi Aramco VSAT Project. He received his Bachelor of
Science Degree in Communications Engineering from the University of Kent, UK, in 1999.
Ahmed has contributed to various projects at Saudi Aramco such as the re-engineering
of the corporate transmission International Network and the Digital Data Network (DDN). Ahmed Al-Baharna
is a member of various professional societies including IEE, The Bahrain Society of
Engineers (BSE), Society of Satellite Professionals International (SSPI), The Internet
Society (ISCO) and the International Engineering Consortium. He has achieved various
awards for his contribution with two presentations “High-Speed Metropolitan
Networks Evolution” in 2001 and “VSAT Applications for Drilling and
Seismic Explorations” in 2002 at the “Communication Engineering Technical
Exchange Meeting” held at Dammam. |
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