Carbonate conclusions

One of 65 research and development centres run by global oilfield services company Schlumberger, Schlumberger Dhahran Carbonate Research Centre (SDCR) was inaugurated in the Dhahran Techno Valley, Saudi Arabia, in 2006. SDCR is the first of its kind in the region, and it is expected to contribute to the development of future oil recovery technology with the collaboration of local companies and institutions. The research centre generates an average of 25 international patents per year.
The centre has two major research programmes: geology and rock physics and production completion and recovery. Schlumberger aims to develop new technologies to be applied for the company’s global operations through the both programmes.

• On dealing with carbonate reservoirs: “There are several major challenges to overcome when dealing with complex carbonate reservoir rocks […] Understanding the pore system, fluid saturation, fluid storage and transport in the porous media is of vital importance. Other subsurface challenges are related to drilling and completion of the wells.”

• On the current state of production: “The easy-to-produce oil days are gone. Exploration and production of hydrocarbons from deep and tight formations and new frontiers like the Red Sea bring new challenges.”

• On further challenges with carbonate plays: “Natural fractures also play an important role in managing and producing these reservoirs. The rock heterogeneity adds another complexity into these rocks, making them more challenging. All of these require a different strategy in terms of drilling, completing and producing the wells.”

• On molecular dynamic modelling: “Manipulating different ions in seawater can provide economic advantage into oil recovery methods. Addition of certain ions with specific percentages has been observed to improve recovery factor by 16% based on lab studies. This approach requires further evaluation and validation in the field.”

Badri also talks about the importance of studying carbonate to help unlock both Saudi Arabia and the world’s oil potential. Most TOGY interviews are published exclusively on our business intelligence platform TOGYiN, but you can find the full interview with Mohammed Badri below.

What challenges are there for producing oil in Saudi Arabia?
Most of the oil in Saudi Arabia comes from carbonate reservoirs that are complex in nature. Oilfield services technologies are developed to perform measurements on simple sandstone formations. However, when dealing with carbonate rocks, several challenges emerge due to the complex nature of these rocks in terms of their pore system, mineralogy and permeability, requiring specialised methodologies to derive key reservoir properties such as fluid saturation and recovery. This could also require modification of existing tools and technologies when we take them downhole into the subsurface.
There are several major challenges to overcome when dealing with complex carbonate reservoir rocks. The main interest of Saudi Aramco and other operating companies in the GCC is to improve recovery factor. Therefore, understanding the pore system, fluid saturation, fluid storage and transport in the porous media is of vital importance. Other subsurface challenges are related to drilling and completion of the wells.
Even though we have been here 11 years and have several workshops every year with Saudi Aramco’s E&P teams, the challenges are never finished providing unique opportunities for collaboration. However, collaboration between Saudi Aramco and Schlumberger has been key factor in pushing technology forward to address the outstanding challenges.
The easy-to-produce oil days are gone. Exploration and production of hydrocarbons from deep and tight formations and new frontiers like the Red Sea bring new challenges. As oil prices have dropped in recent years, pressure has been put on companies to work more efficiently and effectively. Technology will play a significant role in reducing the lifting cost of oil and achieve higher ratio of successful well placement.
Our proximity to KFUPM provides strategic positioning for Schlumberger to work closely with the university students, researchers and faculty members. Since the opening of the centre, we have collaborated with the university through joint research activities, training and co-supervision of graduate and undergraduate students in various specialities.
KFUPM is one of the highly recognised universities in the region, especially in geoscience and petroleum engineering. Joint publications and joint patents have been generated as the result of this collaboration.

Why did you focus on carbonate research for the centre?
Our vision for the centre is to be recognised as a global centre of excellence on carbonate research. Carbonate holds 60-70% of the oil and gas reserves, not just in the Middle East, but also in the Balkan region, Azerbaijan, Kazakhstan and even as far as Malaysia and Indonesia. Carbonates are very important as a place where oil and gas reservoirs are found.
When we started in 2006, our goal was to develop better understanding of the technical challenges facing professionals in characterising carbonate reservoirs. In-depth and detailed knowledge of the pore systems of these complex rocks where pore size range from microns to centimetres provide valuable information on the nature of the fluids and their flow dynamics. Through these pores, the fluids and the gas will flow.
Natural fractures also play an important role in managing and producing these reservoirs. The rock heterogeneity adds another complexity into these rocks, making them more challenging. All of these require a different strategy in terms of drilling, completing and producing the wells.
After this, we started to investigate more about the oil itself. Oil is made of different organic compounds that interact differently with each rock type due to the surface energy dominating the grain surface. Fluid flow in these rocks is governed by the reservoir pressure, fluid viscosity, dominant temperature and relative permeability. They impact the way the oil moves through the pore system. They also have a great impact on recovery.
Today, the recovery factor of oil from carbonate rocks varies from 20% up to 50% of the original oil in place in carbonate rocks. These recovery factors are achieved based on secondary recovery where water injection is used to maintain reservoir pressure and provide the required sweep to move the oil from the peripheral injection wells to the producing wells. Saudi Aramco and other national operating companies aim to improve this recovery factor all the way up to 70%. However, such achievement will require advancement of technology and optimised processes.
Currently, extensive efforts are being devoted to explore and experiment with different recovery mechanisms that would alter rock wettability and improve recovery factor. Fundamental understanding of the rock-fluid interaction at the nano-scale is key. This involves chemicals and physical, thermal, hydraulic and dynamic processes that take place at different scales of the reservoir rock. Our research efforts over the last five years have focused on the characterisation of wettability.

What kind of technologies are you developing for this investigation?
Monitoring and surveillance of reservoir fluids is essential in understanding fluid movement in the reservoir. Studying the interfacial tension of crude oil fluids at elevated temperature and pressure, and developing models to correlate the observation with the theory require extensive efforts and experimentation. We are developing new methods for oil recovery through molecular dynamic modelling.
For example, manipulating different ions in seawater can provide economic advantage into oil recovery methods. Addition of certain ions with specific percentages has been observed to improve recovery factor by 16% based on lab studies. This approach requires further evaluation and validation in the field.
Today there are technologies where reservoir fluids can be monitored such as surface seismic, borehole seismic, single well saturation measurements and cross-well electromagnetic measurements. 3D monitoring of reservoir fluids using surface seismic measurements is challenging especially for carbonate reservoirs that are harder than sandstone rocks.
Therefore, we are currently developing surface to borehole electromagnetic measurements to monitor reservoir fluids based on their resistivity contrast. This method can provide a resistivity map up to two or three kilometres away from the wellbore. This technology development is being carried out in collaboration with Saudi Aramco.

How has the scope of your research changed since you opened up shop?
In the first five years of the opening of the centre, our efforts were focused on rock analysis by conducting specialised studies and evaluation of different technologies, including high resolution sonic, nuclear magnetic resonance, resistivity and dielectric spectroscopy. These efforts resulted in new understanding of the carbonate pore system and oil/water saturation relationship and their capillary behaviour.
However, in the last six years, we have put more emphasis on engineering efforts to develop and commercialise technologies. We put more focus on building actual systems with sensors to examine fluid flow dynamics and develop monitoring technology in the wellbore. Physical measurements using specialised sensing devices based on multi-physics to measure various properties such as temperature, pressure, flow rate and water cut metering were conducted. Sensitivity and validation analyses on the performance of these sensors for various downhole conditions were extensively examined. Further research and engineering work is being done to expand the capability of these sensing technology to detect gas ratios and inter-well saturation mapping using the dynamic data measured downhole.
Schlumberger is making a large capital investment in Saudi Arabia with the building of new factories in the Eastern Province to localise products and employing Saudi graduates from colleges and universities. We have built two factories in the past four years in the Eastern Province and we have plans to build two more new factories. Technology development requires research to develop new concepts, engineering to build systems and manufacturing to bring new products to market. This is our strategy in Saudi Arabia and we have made excellent progress in this direction.

Can your research be applied outside the GCC countries?
Subsurface geological basins are different from place to place. Some development can be applicable globally and others are localised due to the nature of the challenges. Based on our experience across the world, each region has unique set of challenges requiring specialised approaches and solutions.
The fundamental physics and mathematics will not change, however the application varies depending on the problem to be solved. Our goal at the centre is develop new applications based on regional challenges we are facing.

In today’s economic climate, is your focus on getting more from existing wells or is it more in unconventionals?
It is both. Our goal is to help our clients extract more oil out of their conventional reservoirs, as we discussed earlier. In order to maintain production more in-fill wells need to be drilled. Given the current economic climate, Schlumberger has taken important steps to change the way we operate in order to become more efficient and more effective in our approach to market. This is aimed at becoming cost effective and improving the management of our operations.
In 2008, Saudi Aramco and Schlumberger teamed up to develop the new generation of intelligent well completion to improve the performance of the carbonate reservoirs and increase sweep efficiency. The new technology was given the name of Manara, which in Arabic means the lighthouse. It is the flagship of the collaboration between Schlumberger and Saudi Aramco. It has been successfully completed in 2015 and is now fully commercialised. This technology will reduce the cost and will improve the reservoir management on the long term.
Exploration of unconventional resources has been the focus of our technology development. In Saudi Arabia we have been working closely with Saudi Aramco to bring the North American knowledge and skills to the region where Schlumberger has tremendous experience. Our unconventionals team works very closely with Saudi Aramco’s unconventional exploration teams to explore and develop these resources. There are several technical challenges with these unconventional resources requiring further analysis, especially when we dealing with fracturing technologies.

Is your research determined by Saudi Aramco?
The centre was established to work closely with Saudi Aramco and other national oil companies in the region on the technical challenges they are facing. Our research programmes are well aligned with Saudi Aramco’s long terms goals of exploration and improving recovery. Saudi Aramco brings their challenges in well log evaluation, reservoir characterisation and production, and we develop methodology and work flows to address the challenges. Over the last few years we have also worked closely with other national and international companies such as Spain’s Repsol, Malaysia’s Petronas and India’s ONGC.
In addition to working with our clients in the region, we have also our own internal research activities. These include geomechanics, matrix stimulation, enhanced oil recovery methods and surface chemistry. It involves concept development through modelling, lab experimentation, field yard validation and downhole implementation.

What is your assessment of the unconventional potential of Saudi Arabia?
Saudi Aramco has recently embarked on an aggressive exploration and exploitation programme of unconventional resources in Saudi Arabia. There is huge potential for unconventional resources in Saudi Arabia. The large basins of the country exhibit large potential for natural gas reserves from unconventional and tight rocks. The Jafurah Basin located south of the Ghawar oilfield is an excellent example of a high-potential basin.
These tight formations require hydraulic fracturing to produce. Fracturing these formations requires a large amount of water, bringing new challenge on the availability of such water. Research activities are currently focused on reducing the amount of water used in fracturing or even developing waterless fracturing methodologies. Recent drilling and completion activities targeting these tight formations have demonstrated the potential of these formations to produce natural gas. Further analysis and testing of these formations will shed new light on their potential to produce economically.

Are you intent on expanding operations at the centre?
We have a very good future outlook. Obviously, we want to grow and expand our activities. Today, we are restricted in terms of our R&D spending due to the current economic climate. However, our plan is to grow in terms of adding more human resources and expand our research lab capabilities. We will be diversifying and broadening our research portfolio as we move forward to address the growing challenges of the industry.

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