Exploiting Deep-gas Resources through Advanced Geophysical Technology
This workshop reviewed and discussed the current status of deep gas exploration in the Middle East using various geophysical techniques that include basin definition and modeling, seismic survey design, data acquisition, data processing workflows, interpretation, rock physics, log analysis, and drilling challenges.
The Middle East region is in need of energy to support the economic growth. In order to address the demand for energy, NOCs and IOCs are exploring for new gas reserves in deep, hot, and very tight formations varying from shale, sandstone and carbonate rock types. Some of these formations are classified as source rocks and organic material-bearing from which natural gas can potentially be produced. However, they are very challenging to find, drill, and produce economically.
This workshop also considered potential field methods such as magnetic and gravity measurements, with prime emphasis placed on integration of the various measurements into the exploration workflow. The results of the workshop have impacted exploration and drilling strategy, improved current workflows, identified technology gaps, and helped define the road map for future evaluation of these reservoirs.
- Basin analysis and modeling
Basin analysis and modeling consider as a compulsory tool to explore undiscovered deep reservoir targets and to plan the appropriate development approach. Data integration and characterization are the keys to undertake basin analysis and modeling study. This will allow to evaluate the resources potential as well as describe the geologic controls on hydrocarbon system. The principal objective of basin analysis and modelling is to develop the concept that petroleum systems acting in a basin can be identified and used in providing more reliable and advanced approach for targeting more challenging and deep reservoir targets.
- Advanced seismic acquisition & processing
- Advanced seismic imaging
Exploring for new gas reserves in the Middle East bring companies into deep and complex geology that requires the best technology and innovation to properly image the deep-subsurface. 3-D Seismic imaging technology plays a very important role in the exploration of new prospects at deep depths. However, this is not a simple operation. It now involves big areas to cover, careful design, simulations, tests, longer cables, wide azimuth, big amount of digital data (thousand of terabits), big computational center, excellent positional and communication system and longer processing periods. There are already good examples and workflows applied in and outside the Middle East but technology is continuously changing and we aim during this workshop to know and share what is happening in our region. Certainly, seismic data is the tool in the petroleum industry to get the more realistic image of the geology in the subsurface.
- Innovative seismic technology
- Role of potential field methods
Gravity and magnetic methods have increasingly demonstrated their ability in complementing and constraining traditional seismic methods in hydrocarbon exploration, as well as reducing risk and improving profitability of oil and gas business in general. Advances in satellite altimetry, global positioning systems (GPS), airborne gravity and gravity gradiometry have dramatically improved our ability to acquire higher resolution gravity data and map oil bearing traps in more details. Examples of borehole-gravity aiding in detecting porous zones are enlarging the application spectrum of gravity methods. Such recent developments have increased the impact of gravity data on exploration applications. Classically, airborne magnetic methods are relatively inexpensive and powerful tools for mapping strongly magnetic (primarily basement) structures. The deep channel systems may be revealed magnetically as they may cut into magnetic horizons or they could hold magnetic material deposited in environments that are not magnetic. By using the modelling software and integrated interpretation with other geophysical data like EM, apart from seismic data, deeper and more complex details may be extracted from airborne gravity and magnetic surveys.
- Borehole geophysics and microseismic
The use of surface seismic for reservoir characterization and monitoring becomes particularly challenging for deep gas reservoirs (attenuation, multiples contamination, etc.). Borehole seismic and microseismic should play a major role to overcome those challenges. Combined with wireline logs, VSP data provides better understanding of the actual reflectivity versus imaging artifacts, therefore enhancing the reliability of quantitative seismic reservoir interpretation. Closer to the completion/production mechanisms, the improvements in borehole microseismic acquisition and interpretation brings valuable information for reservoir management.
- Reservoir evaluation and characterization
Reservoir evaluation and characterization cover wide range of measurements that require integration. 3-D seismic data, well logs, core data and fluid properties are essential in building reservoir models. In this session, we will examine how sweet spots are determined from well data and how this information is used to guide exploration and exploitation of deep gas reservoirs using 3D seismic. These reservoirs are deep, very tight with porosity less than 5 pu and permeability in the nano-Darcy range. Reservoir quality in terms of mineralogy and facies is of prime importance when characterizing these reservoirs. Organic content (TOC) and their maturity play an important part in the characterization process. Pore pressure and depth of burial need to be carefully considered when dealing with these reservoirs.
- Reservoir Engineering and fracturing
Deep gas and unconventional resources is an area where technology has been leading the developments in geoscience and reservoir engineering. These resources have also brought on the rapid evolution of horizontal well staged fracturing technology. The emerging trends in reservoir engineering and workflows of these deep gas and unconventional reservoirs will be reviewed and key differences between conventional and unconventional resources will be discussed.
- De-risking drilling with geophysical solutions
Modern geophysical techniques, particularly 3D Seismic data acquisition and processing methods, have several applications in de-risking exploration targets in terms of both time and capital expenditure. Thus, the oil and gas industries have seen a remarkable half a century of scientific and technological expansion in geophysical methods and this growth is continuing. New exploration frontiers and exploitation of complex and unconventional reservoirs are being made possible with such advances.
A few key advanced seismic applications include: imaging below thick layers of salt in the deep seas; seismic-while-drilling techniques using the drill bit as the seismic source; and seismic guided drilling. Seismic attributes such as amplitude variation with offset (AVO) have become an effective tool to address reservoir risk. While seismic attributes support accurate mapping of faults, assessment of reservoir seals and charge, and migration patterns, they also help detecting shallow gas hazards prior to drilling. Pore pressure and over pressure prediction using seismic data reduces the risk and saves the the industry large amounts of money every year. Integration of seismic, 3D VSP, and microseismic mapping of induced hydraulic fractures helps understand the magnitude, direction, mechanisms and lithological controls on hydraulic fracturing and well completion. Thus, the benefits of integrating geophysical technologies with other disciplines are enormous in terms of de-risking exploration targets in terms both time and capital expenditure. While, historically, engineers and geologists have been responsible for reserve estimation, geophysicists now play a critical role.
Abdulmohsin Dolaijan, GEOTECHNOLOGY AND SERVICES
A. Nabi Mukhtar, BAPCO
Adnan Omar Bu Fateem, MUBADALA PETROLEUM
Badria Abdul Raheem, KOC
Bill Lindsay, BAKER HUGHES
Mahfoud Al-jenaibi, ADCO
Mohammed Mugheiry, OOCEP
Fred Mittaine, CGG
Pedro Balaguera, PDO
Simon Robinson, ANADARKO
Petroleum Development Oman
- Official Program: File:2014 SEG Deep Gas Workshop Program educed.pdf