Offshore Drilling Lecture 2016 Unit 3 [PDF]

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Offshore Drilling and Production Unit III



Prof. (Dr) Sreepat Jain Prof. (Dr) Sreepat Jain: Offshore Drilling



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Course Content



Unit – III Deep water technology: Introduction definition & prospects. Deep water regions, Deep water drilling rig – selection and deployment, Deep water production system, Emerging deep water technologies – special equipment and systems Remote operation vessels (ROV) Divers and Safety: Principles of diving use of decompression chambers, life boats, Offshore Environmental Pollution and Remedial Measures.



Prof. (Dr) Sreepat Jain: Offshore Drilling



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Onshore



Joe Leimkuhler, offshore well delivery manager for Shell Upstream Americas, explained that the average U.S. well produces about 10 barrels of oil a day.



Offshore



Current scenario



The average offshore deepwater well, in contrast, produces 1000 barrels per day.



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Current scenario Oil will remain the dominant fuel in the global energy mix through 2035, even if current efforts at fuel efficiency and alternatives are included in the calculations, by the International Energy Agency's (IEA) projection. Worldwide oil demand is on track to climb 18% in the next 25 years, to 99 million barrels per day. So the oil industry continues to seek new frontiers, and some of the most promising happen to be under the sea. More than half of all the oil that has been discovered since 2000 is in deepwater, says IEA. The energy consulting firm IHS CERA projects global deepwater capacity will more than double by 2030, to 11 million barrels per day. Prof. (Dr) Sreepat Jain: Offshore Drilling



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Current scenario



Prof. (Dr) Sreepat Jain: Offshore Drilling



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BP's Macondo well 



April 20, 2010



The high pressure characteristic of these reservoirs ‐ the reason BP's Macondo well was so hard to control, has come under intense research.



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Deep water regions



Arctic



GOM



W Africa Brazil



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Deep water regions: The Gulf of Mexico The Gulf of Mexico, with more than 3,400 offshore production facilities, has much more in deeper water and in older geological formations. Estimates suggest that the Gulf has nearly 13 billion barrels of recoverable deepwater oil. "In the Gulf the hottest spot is something called the Lower Tertiary,". BP's Macondo well, was in Miocene, 25 million years old or less. The Lower Tertiary (~60 Ma) lies about 200 miles off the Gulf Coast and extends from Alabama to Mexico. The deepest oil‐producing structure in the world is here ‐ Shell's Perdido production platform. The Perdido complex retrieves both oil and gas from reservoirs more than 8,000 feet (2,438 meters) below the water's surface. Prof. (Dr) Sreepat Jain: Offshore Drilling



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Deep water regions: Brazil 2007 discovery of Tupi field, 200 miles south of Rio de Janeiro, was a game changer. Brazil has nearly 48 billion barrels of oil in water depths of 2,000 feet (610 m). "It's relatively light (easy to refine) and it's huge,". "But it's challenging. It's in some 6,000 feet (1,830 meters) of water and, more importantly, it's below a layer of salt.“ Salt layers often accompany oil reserves, but they create challenging conditions, because the salt tends to rise up thousands of feet through overlying rock. "What happens is that the rock that's adjacent to this salt, which was originally laid down flat, gets sort of pulled up like a rubber band that's attached to something,". As a result, the rock formation gets broken into pieces, and "when you go in there, one can often lose circulation". That means drilling fluid, the heavy mud which helps control pressure, can be lost to the surrounding ground rather than recirculating through the well system". Prof. (Dr) Sreepat Jain: Offshore Drilling



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Deep water regions: West Africa The two biggest players are Angola and Nigeria, which between them have more than 20 billion barrels of proven deepwater reserves. "It's young rock and it produces like crazy". “….once predicted that they would reach 100,000 barrels a day from a single well.” Nigeria, which produces especially desirable "light, sweet" crude, was Africa's top oil producer, but slipped due to political unrest. Angola vies with Nigeria as Africa's top producer of crude oil, but it has its own political problems, particularly in the oil‐rich Cabinda province. Ghana, Liberia, and Sierra Leone are set to join the ranks of Africa's offshore producers. Jubilee well off the coast of Ghana and Sierra‐Leone‐Liberian basin Prof. (Dr) Sreepat Jain: Offshore Drilling



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Deep water regions: Arctic



Frigid temperatures, high seas, shrieking winds, darkness, and minimal visibility mark the offshore areas of the Arctic. But there is a lot of oil beneath it all. The USGS estimates the Arctic holds 13 percent of the world's undiscovered oil ‐ 90 billion barrels recoverable with current technologies and practices. USGS also estimates the Arctic holds 30 percent of the world's undiscovered natural gas. The Arctic's offshore oil is not in deepwater (in less than 1,640 feet (500 m). But accessibility is a huge problem; the nearest U.S. Coast Guard Air Station to the Beaufort and Chukchi seas is 950 miles (1,530 km) away, and the nearest major port lies 1,300 nautical miles (2,400 km) distant. In all, eight separate nations share claim to the Arctic's 11.6 million square miles (30 million square km). Prof. (Dr) Sreepat Jain: Offshore Drilling



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Offshore Oil/Gas Production Systems



Offshore Oil/Gas Production Systems Brief History of Offshore Production Systems Various Types of Offshore Platforms  Bottom‐supported Platforms  Floating Platforms  Subsea Production Systems  Subsea Christmas Trees  Subsea Manifolds  Subsea Boosting and Processing  Subsea Control System 



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Brief history of offshore production systems Oil wells were initially drilled from piers constructed along the coast. Such bottom‐supported platforms have been in use ever since, though material to build them changed from wood to steel and concrete. These platforms, whilst good in that they can provide working environment probably closest to that onshore, have problems of sharply increasing cost with increasing water depth and long lead time for construction. To counter these problems, the petroleum industry came up with floating platforms in the 1970s. These include semisubmersibles, a natural functional extension of their sisters in the MODU fleet, ship‐shaped floating production storage and offloading systems (FPSOs) and tension leg platforms (TLPs). Prof. (Dr) Sreepat Jain: Offshore Drilling



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Brief history of offshore production systems To date there are >1000 wells worldwide drilled and completed subsea. The advancement of subsea technology meanwhile has led to development of other kinds of equipment tailored for subsea application: 1. manifolds to collect/divert produced & service fluids to desired flow paths, 2. multi‐phase pumps that can boost pressure of the mixture of gas & liquid 3. gas/liquid separators, all with associated controls equipment. However, research and development still continue to tap oil and gas in still deeper water and still harsher environment.



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Prof. (Dr) Sreepat Jain: Offshore Drilling



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Various Types of Offshore Platforms



Bottom‐supported Platforms These are the most widely used platforms (Template platforms). They consists of jacket, piles and deck. The jacket is fixed to sea bottom by means of piles and they together support the deck load. The deck is the topside structure of the platform and houses most of the equipment. The deck is usually divided into several modules, which are individually fabricated at a yard or shipyard, transported on a barge to the site where the jacket is already installed, lifted and fixed onto the jacket. Prof. (Dr) Sreepat Jain: Offshore Drilling



Template platform 16



Compliant towers and Gravity platforms As the water depth increases, maintaining stiffness to rigidly becomes increasingly difficult and prohibitively expensive. The alternative is a structure that must have much longer sway period than that of high‐energy storm waves, avoiding resonance of structures with these waves. This type of platforms is called compliant towers and has been applied in water depths in excess of 500 m. Another type of bottom‐supported structure is the gravity platforms. They derive required stability from their own weight. Prof. (Dr) Sreepat Jain: Offshore Drilling



Gravity platform 17



Floating Platforms Though the bottom‐founded platforms provide stable working environment, they typically have the drawbacks of: long lead time and cost tendency quite sensitive to water depth. A solution to these problems has been the floating platforms moored to the seafloor. An additional advantage is seen in ease of relocating and reusing them after a field is depleted.



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Floating Platforms Mooring is usually by eight to twelve point catenaries. Motion of the platform does not allow wells to be completed on the deck. So they are usually completed subsea and produced fluid is brought to the processing equipment aboard the platform by means of pipeline and riser. Riser is one of the technical focal points and flexible pipes are widely used for this application. Disadvantages of this type can be summarized as limited payload capacity and lack of storage capability. Prof. (Dr) Sreepat Jain: Offshore Drilling



Semisubmersible Platform



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Floating production storage and offloading system (FPSO)  Another type of floating platform is the  floating production storage and  offloading system (FPSO).  They are ship‐shaped platform either with or  without propulsion capability.  FPSOs have a large payload and storage  capacity making them suitable for  application in isolated locations where  pipeline transportation cannot be an  option.  Single point mooring is the most widely used  station‐keeping means, where the  platform is allowed to weathervane  around the mooring mechanism.  Multi‐point moorings have been applied in  relatively benign environment such as  West Africa and the Gulf of Suez.  Prof. (Dr) Sreepat Jain: Offshore Drilling



Floating production storage  & offloading system (FPSO)  21



Floating production storage and offloading system (FPSO)  Advantages of FPSOs are:  Earlier cash flow because they are faster to develop than  fixed platforms  Reduced upfront investment  Retained value because they can be relocated to other fields  Abandonment costs are less than for fixed platforms Over the years, advanced mooring systems as well as  advancements in subsea equipment have made FPSO/FSOs useful in deeper and rougher waters.  Currently, approximately 160 FPSOs and 100 FSOs are in  operation worldwide



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Floating storage and offloading system (FSO)  The difference between the systems is  that the FPSO is also directly connected  with the oil drilling while the FSO is only  concerned with storage.



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Tension Leg Platform (TLP)  A floating platforms specifically developed for deep‐water application. Platforms of this type are in water depths in excess of 500 m and the deepest application is in more than 1200 m of water. TLP is essentially a semisubmersible attached to the seabed by vertical members called Tendons, which are usually made of steel tubulars & tensioned by excess buoyancy of the platform hull. Tendons are pinned to the seabed directly or indirectly by piles. Motion characteristics of the TLP allows wells to be completed on its deck, a big advantage because wells are one of the most important and expensive components of a petroleum production system and ease of access to them is a matter of prime concern in field development. Prof. (Dr) Sreepat Jain: Offshore Drilling



Tension Leg Platform 24



Spar platform, or deep‐draft caisson vessel (DDCV)  The most recent species of floating platform is the spar platform, or deep‐draft caisson vessel (DDCV). As its name indicates, it has a deeply submerged, spar‐shaped hull and a deck structure. The platform is moored to the seabed by means of catenary or taut mooring. Like TLP it is possible to put Christmas trees of wells on the platform deck, and like FPSO, oil storage capability can be incorporated in the hull, making this type attractive at isolated deep water locations



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Spar platform, or deep‐draft caisson vessel (DDCV)  Spar relies on its deep draft (most of the section is submerged) and large effective mass to keep vertical motions within an acceptable range. Advantages of the Spar Less sensitive than TLPs to water depth and payload Allows surface wellheads (dry trees) Vertical access to wells Support of remote wells Drilling and workover capability Active lateral mooring system can provide drilling access to a large well pattern Limitations of the Spar More extensive offshore campaign for integration and installation Sensitive to long period waves Support of TTRs (Top Tensioned Risers) in very deep water Limited centerwell space for large numbers of TTRs



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Subsea Production Systems



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Subsea Production Systems Reservoirs discovered close to existing infrastructures or parts of producing reservoirs too far away to reach from existing platforms are typically developed utilizing subsea wells tied back to the host platforms, providing economical means of field development. Also exploratory wells, typically plugged and abandoned after a short period of test not so long ago, are completed subsea and put into production for some months using drilling vessels equipped with temporary production facilities or purpose‐built well test vessels, providing valuable reservoir data for subsequent field development planning.



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Subsea Christmas Trees Subsea trees are, like land trees, primary means of flow control for subsea wells and consist of series of valves and sometimes a flow control device (choke) along the flow path of produced fluid with associated controls equipment. They are installed by drilling rigs using guidelines established between a pre‐installed guide base structure and a rig for positioning and orientating. For deep waters where use of guidelines is not practical, guidelineless system is available.



Subsea Christmas Tree 



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Well Template



Where it is desirable to drill a number of wells from one location, a well template is used. A template is a steel structure that provides structural support and appropriate spacing to wells. As the drilling rig can move from one well position to another only by adjusting anchor lines, use of template can bring savings in drilling cost.



Prof. (Dr) Sreepat Jain: Offshore Drilling



Well Template



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Subsea Manifolds A manifold consists of appropriately arranged valves and pipings with associated controls equipment and a structure to support these components. It allows produced fluid to be commingled or diverted and injection fluids to be distributed to desired flow paths. With a subsea manifold, number of flowlines and injection lines between wells and host platform can be reduced substantially, saving large amount of investment. Disadvantage is added complexity in not‐easily‐ accessible subsea environment with implications on maintenance cost. Flowlines are pipe lines that connect a single wellhead to a manifold or process equipment. In a larger well field, multiple flowlines may connect individual wells to a Prof. (Dr) Sreepat Jain: Offshore Drilling manifold.



Subsea Manifold



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Subsea Boosting and Processing



Most subsea wells will flow naturally to the production facility for a period of time; however, as the reservoir pressure declines to a point where the well can no longer produce to the host platform, the well will completely shut down ‐ even though the reservoir may still have sufficient pressure to produce to the seafloor. This situation leaves significant oil in place that can be captured with seabed booster systems.



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Subsea Boosting and Processing



Wells, templates and manifolds have been successfully applied subsea. The next candidates for subsea application are multi‐phase pressure boosters and fluid separators. The idea behind the multi‐phase pressure booster, or multi‐phase pump, is that if pressure boosting can be done at the subsea wells, a platform long distance away can be their host, widening the possible range of step‐out development. Installation of a subsea multiphase booster pump increases the pressure in the well fluid, i.e. adding kinetic energy directly to the flow. The effect is as if the flowing wellhead pressure is increased. The flow from the wells increases until a new balance between fluid pressure and system resistance is achieved. The effect is a net increase in oil production. More ambitiously, produced fluid could be sent directly onshore, eliminating the need for host platform altogether. The overall cost of installing a subsea pump station relative to an FPSO, or platform is low, and offers benefits in terms of producing challenging fields, with low investment payback time. Prof. (Dr) Sreepat Jain: Offshore Drilling



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Subsea Boosting and Processing



While several wells can be produced through one vertical booster station, this set up eliminates the ability to optimize flow from each well, as the same pressure boost is applied to each well and, therefore, the system is limited by the lowest producing well.



Prof. (Dr) Sreepat Jain: Offshore Drilling



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Subsea Control System



In order to ensure safe and efficient operation of the subsea production systems, their various components such as valves, chokes and connectors must be properly controlled. Control systems currently employed utilize hydraulics and often electronics to differing degrees. Of these most commonly used is the electro‐hydraulic multiplexed system. The system requires hydraulic power supplied from the host platform to actuate control devices. Electric power is usually supplied through a separate cable, but superposition of data signals on the power cable has been successfully tried.



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Subsea Control System



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Remote operation vessels (ROV)  Remotely operated vehicles (ROVs) have facilitated the development of oil and gas resources in deeper water and have extended capabilities for handling more complex situations and operations in deeper water. In the 1980s, divers used saturated and pressurized systems to do almost all well and subsea equipment intervention, inspection, and repair. If the divers could not complete the repair task and/or inspection, the blowout preventer (BOP) stack or other items had to be pulled out of the water for repair. Even with the most sophisticated equipment, divers had limited capabilities, because of variables such as: Water depth Visibility Currents Temperatures, Bottom downtime Sometimes, questionable safety standards Subsea television systems were, and still are, used to inspect and monitor hulls and subsea equipment by use of running down guidelines, but they can only view (not do) repairs or other physical tasks. Prof. (Dr) Sreepat Jain: Offshore Drilling



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Remote operation vessels (ROV) capabilities Modern ROVs have the ability to “fly” by means of an umbilical that is attached to the transport cage (or “garage”). Once the ROV leaves its cage, it may traverse for approximately 100 ft. The operator, or pilot, controls the flight pattern and position of the ROV, so it will not become entangled in its own umbilical or other items. Most ROVs have visual and recording capabilities, in addition to manipulator arms with various degrees of strength, feedback, and lifting capability. ROV technology has far exceeded water depth ratings of MODUs; the capabilities and reliability of these units have improved considerably. Common tasks include: Changing of wellhead sealing ring gaskets Control of some functions on the BOP stack in an emergency Retrieval/installation of items on the wellhead or production hardware Inspection, as well as inspections with the subsea television system Prof. (Dr) Sreepat Jain: Offshore Drilling



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Emerging deep water technologies: the three Quadrants Bohr quadrant Edison quadrant Pasteur quadrant For new advances, scientists talk about three ‘quadrants’ of research: firstly, the ‘Bohr quadrant’ – named for atomic physicist Niels Bohr – is pure, basic ‘blue sky’ research. The ‘Edison quadrant’ – named for Thomas Edison, inventor of the light bulb – covers applied research, focused on specific uses. Then, there is the ‘Pasteur quadrant’ – named for the French microbiologist Louis Pasteur – a hybrid area where scientists have one eye on advancing fundamental understanding and the other on how such advances can be applied. Prof. (Dr) Sreepat Jain: Offshore Drilling



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Emerging deep water technologies: the three Quadrants Two‐thirds of our upstream technology development spending goes into the Edison area, as one might expect, but nearly a third is invested in the Pasteur quadrant. This is because Pasteur is where cutting‐edge, game‐changing technologies come from. Until recently, our industry has been about horsepower: heavier equipment, thicker steel, more water injected and so on. But the future is going to be more about being smarter. And that means greater understanding of fundamental science.



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Emerging deep water technologies



"The next generation of advances may depend not only on how innovative we can be, but how collaborative."



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New materials



Advancing materials science, for example, offers many possibilities, using crystallography, nanotechnology, atomic structure, thermodynamics, kinetics and other specialisms to create new alloys as well as self‐healing coatings and other forms of tougher, more corrosion‐resistant infrastructure. Such teams are effectively building a next generation of equipment for an industry that is already operating complex sub‐sea systems that resemble underwater cities.



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New materials



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Mastering Deep‐water Challenges Anti‐freeze Deep‐water projects operate in sub‐zero temperatures, powerful sea swells and frequent storms. Low sea temperatures combined with high pressure in the pipes cause blockages. Hence, a glycol‐based liquid is injected into the pipes which dilutes the water in pipes & prevents it from turning into ice‐like hydrates & blocking the flow. When the well stream reaches shore, the anti‐freeze is separated and recycled back into the system. Pressure boosters Reservoir pressure is not strong enough to push oil to the platform above. Remote‐controlled submarines helped to install electric pumps on the seabed. Storm safe Tropical storms are common. To anchor the platform securely, engineers used a remote‐controlled robot to attach it to four giant mooring lines, each weighing 150 tonnes. The lines secure the platform against waves of up to 8 m (25 feet) and winds that can gust at hundreds of kilometres an hour. Prof. (Dr) Sreepat Jain: Offshore Drilling



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Challenges and solutions



Exploration 1. Subsalt depth imaging 2. Evaluate reservoir for internal characterization 3. Improve exploration success by maximizing seismic information 4. Seismic imaging in narrow mini‐basins 5. Limited geologic/analogue well information Drilling 1. Access reservoirs previously inaccessible due to extremely low ECD margins 2. Salt creep 3. Increase drilling tool reliability in ultra‐deep wells in hard formation environments 4. Reduce non‐productive time (NPT) 5. Manage complex well trajectories in development projects 6. Salt exit strategy 7. Alleviate environmental risks using synthetic‐based, high‐performance fluids Completions and production 1. Manage reservoir with intelligent completions and multilaterals 2. High completion cost 3. Increase recovery factor 4. Ensure well integrity in reservoirs with high content of H 5. Manage complex well trajectories in development projects 6. Salt exit strategy 7. Alleviate environmental risks using synthetic‐based, high‐performance fluids Prof. (Dr) Sreepat Jain: Offshore Drilling



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Exploration



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Subsalt Depth Imaging



Challenge How can I improve imaging of the subsalt structures so I can plan wells more accurately, and reduce drilling uncertainty? Salt sections are particularly unpredictable, making them very challenging to drill and cement. Salt zones are notorious for causing problems such as stuck pipe, wash out, or casing collapse, making it difficult for operators to stay within the authorization for expenditure and avoid non‐productive time. Solution Salt structures are complex and seismic velocities vary abruptly because of faulting or salt intrusion, depth imaging is absolutely required to define the true position and correct geometry below the salt. We need better visualization tools that allows rapid viewing of seismic data. Seismic data processing, must be used for multiple applications: from field processing and quality control, to interpretive project‐oriented reprocessing and production processing. Prof. (Dr) Sreepat Jain: Offshore Drilling



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Subsalt Depth Imaging Provide the most value to the well construction process include drillstring integrity,  hydraulics management and wellbore integrity. Drillstring integrity focuses on: • prevention of mechanical overload • protection from fatigue • minimizing excessive shock and vibration. Specialized software is used to model every bottom hole assembly (BHA) & drillstring. Hydraulics management focuses on: • maintaining annular pressures within wellbore pressure boundaries • optimizing hole cleaning and clean‐up cycles • optimizing circulating system pressures • maximizing ROP (Rates of Penetration) without exceeding mud weight windows • optimizing tripping time Wellbore integrity focuses on: • defining wellbore pressure limits • identifying the optimum mud weight window. Prof. (Dr) Sreepat Jain: Offshore Drilling



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Evaluate Reservoir for Internal Characterization Challenge How can I more accurately characterize reservoir rock & fluid properties to better estimate reservoir potential, design more effective wells & avoid drilling hazards? Solution Accurate reservoir characterization and modelling must leverage: 1. core samples, 2. downhole formation evaluation measurements, 3. seismic visualization technology, and 4. seismic imaging techniques to help better understand the spatial distribution of reservoir properties including: 1. lithology, 2. porosity, 3. permeability, 4. fluid saturation and 5. pore pressure. Understanding favourable or hazardous reservoir properties enables operators to design more effective drilling & production programs while avoiding drilling hazards & unnecessary risks. Prof. (Dr) Sreepat Jain: Offshore Drilling



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Improve Exploration Success by Maximizing Seismic Information



Challenge How can I gain a better understanding of my prospect, find new reserves and identify drilling targets more quickly? Solution Superior integration of: high‐resolution visualization data, and seismic volume interpretation from basin to reservoir scale can provide valuable insights into the hydrocarbon source, migration patterns, maturation and trapping. It can also enable a detailed characterization of the potential reservoir, enabling the successful exploration of reserves and identification of the best drilling targets.



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Seismic Imaging in Narrow Mini‐Basins Challenge How can I use detailed prospect and reservoir analysis to speed up: critical workflows, generate higher‐resolution seismic images, and increase interpretation accuracy with an improved understanding of structures overlaying the sub‐salt? Solution West Africa’s deepwater mini‐basins are filled with a variety of sedimentary gravity‐ flow deposits, all of which have distinct seismic facies. Both the salt cover and the steep dips in these mini‐basins hinder sub‐salt seismic imaging and seismic‐attribute analysis that are critical to understanding these depositional systems. Traditional salt‐imaging methods make it difficult to discern their structure. From acquisition to: 1. earth modeling, 2. accurate velocity estimation and 3. depth imaging provides the key to understanding formation evaluation below the surface ‐ before costly drilling decisions are made. Prof. (Dr) Sreepat Jain: Offshore Drilling



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Limited Geologic/Analogue Well Information Challenge How can I improve pre‐well planning accuracy in areas of high uncertainty where little or no analogue well control is available? Solution Reservoir prediction in the Lower Tertiary trend requires locating the dip‐oriented slope and submarine fan systems. Depth imaging helps unravel the complicated wave propagation that can so often degrade image quality and resolution, and helps identify sedimentary structures below complex overburden. Combined with geostatistical methods provides best case scenarios.



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Drilling



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Access Reservoirs Previously Inaccessible Due to Extremely Low ECD Margins Challenge How can I stay within the window to maintain well control while avoiding fluid losses and formation damage? Solution Activities such as: circulating fluids, running and landing casing and liners, and cementing contribute to a pressure in the wellbore that can be expressed in terms of equivalent circulating density (ECD), which is additional pressure to the formation that can induce fractures and lost circulation. The objective of ECD management is to stay within the pore pressure and fracture gradient window to mitigate these issues. Specific drilling challenges include: having fluid systems capable of maintaining the hydrostatic pressure of the fluid column, while avoiding barite sag or lost circulation. Prof. (Dr) Sreepat Jain: Offshore Drilling



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Salt Creep Challenge How can I manage salt creep and prevent well failure, ensuring long‐term producibility and wellbore access? Solution Salt formations in the Gulf of Mexico can flow plastically, causing the borehole to close in around the drill string. These creeping salt masses can exert catastrophic stresses on well casing. The salt moves faster in areas of elevated temperature, or where large differential pressures exist between the drilling mud weight and formation pressure. A well designed and executed cementing plan is a key factor in mitigating salt creep and ensuring long‐term well viability. Prof. (Dr) Sreepat Jain: Offshore Drilling



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Increase Drilling Tool Reliability in Ultra‐deep Wells in Hard Formation Environments Challenge How can I increase drilling tool reliability in harsh drilling environments? Solution In deepwater hard formation drilling environments, extreme stresses are placed on downhole tools‐‐which mean higher risks for failure. Downhole shock and vibration can reduce drilling penetration rates, reduce borehole quality, and damage downhole tools, all leading to expensive non‐productive time (NPT). Measuring, modeling and optimizing drillstring integrity, vibration and hydraulics during the drilling process can mitigate the harmful effects of deepwater stresses on drilling equipment. Another way to optimize drilling practices is to closely examine drill bit performance. Prof. (Dr) Sreepat Jain: Offshore Drilling



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Reduce Non‐Productive Time (NPT) Challenge What steps can I take to optimize my drilling program, reduce unplanned events and minimize drilling risk – even in long‐reach, high‐angle wells? Solution Typically, NPT accounts for up to 32 percent of drilling operation costs for deepwater wells causing billions of dollars in incremental costs each year worldwide. Unplanned events can cripple any drilling program. With the high cost of exploration wells currently being drilled in deepwater, minimizing these events and more effectively predicting what lies ahead can pay huge dividends by helping operators stay on budget, reach total depth on time and execute a successful drilling operation. Hence, well and field planning cycle times and cost‐effective designs can reduce NPT.



Prof. (Dr) Sreepat Jain: Offshore Drilling



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Manage Complex Well Trajectories in Development Projects Challenge How can I best plan and drill complex trajectories to hit the most productive reservoir targets? Solution Finding and reaching relatively small targets often requires complex well trajectories. Many development wells are drilled from fixed installations. The resulting well paths require precise wellbore positioning to navigate around existing wells, reach smaller targets and obtain proper trajectories through and around salt bodies. Collaborative well planning software, with 3‐D multidiscipline data visualization, automated planning features and scenario sensitivity analysis can help planners more effectively optimize platforms while creating trajectories to reach multiple targets with a minimum number of wellbores. Geosteering software uses geological information and dowhnole technologies to enable complex wells to be guided to the reservoir. Rotary‐steerable tools provide smooth wellbore trajectories while azimuthal, deep‐reading LWD sensors help make real‐time adjustments to stay in thin reservoir sections. These technologies can be used to optimize wellbore placement while maintaining well trajectory to remain near the top and maximize recovery. Prof. (Dr) Sreepat Jain: Offshore Drilling



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Salt Exit Strategy Challenge How can I best understand the unknowns with predicting and exiting the base of salt so I can best plan my exit strategy and conduct proper risk assessment? Solution Exiting salt and drilling the formations immediately beneath can pose significant hazards to drilling operations. The solutions to drilling through and beneath salt can be categorized in two ways. First, services should be used that improve understanding of the drilling environment both in the open hole and ahead of the bit. Second, services should be used that mitigate or reduce the severity or issues that cannot be avoided, such as low penetration rate, unexpected tar formations, inclusions and wellbore cavings. The first type of services can help engineer risks out of the project, and the latter help manage challenges that are unforeseen or unavoidable due to the constraints of the program. An early challenge in most sub‐salt projects is to develop an accurate pre‐project assessment of the in‐situ stress and pore fluid pressure. From this a well plan can be created and subsequently optimized. The addition of wellbore stability, salt creep and casing collapse analyses are also available to ensure the drilling fluids and casing programs are designed to minimize risk, and reduce the probability of overdesign and inefficiency. Real‐time measurements and analysis can help pick the right casing seat, avoid troubles like wellbore instability or kicks, and manage unexpected events such as lost circulation or changes to the drilling program which require revised drilling tools. Prof. (Dr) Sreepat Jain: Offshore Drilling



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Alleviate Environmental Risks Using Synthetic‐based, High‐performance Fluids Challenge How can I ensure the best environmental performance in my drilling fluid choices? Solution Synthetic‐based fluids have helped reduce the risk of severe downhole losses and reduced overall well costs on many deepwater projects while providing an environmentally friendly alternative to oil‐based fluids. Low toxicity mineral oils are unlikely to meet many recognized industry standards to evaluate biodegradation properties of base oils. One of the most basic functions of drilling fluid – the suspension of solids – has been radically improved, leading to exceptional drilling performance and an unprecedented reduction in mud losses. Clay‐free invert emulsion systems, stable to 350°F, have helped reduce the risk of severe downhole losses and reduced overall well costs on many deepwater projects while providing best available environmental performance. Prof. (Dr) Sreepat Jain: Offshore Drilling



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Completions and Production



Prof. (Dr) Sreepat Jain: Offshore Drilling



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Manage reservoir production with Intelligent completions Challenge How can I best manage my reservoir production over an extended period of time and keep it profitable? Solution Promising technologies such as intelligent completions and multilateral systems in high‐risk terrains enable efficient drainage of complex reservoirs and have long‐ lasting benefits for the reservoir's profitability. Intelligent completions allow the operator to produce, monitor and control the production of hydrocarbons through remotely operated completion systems. Today, the proven reliability of these systems helps cost‐effectively enable some of the world’s most sophisticated completions. An intelligent well enables the operator to reduce intervention, remotely monitor and control downhole fluid flow, and optimize well production and reservoir management processes in order to maximize asset value. Prof. (Dr) Sreepat Jain: Offshore Drilling



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Manage reservoir production with Multilaterals Challenge How can I best manage reservoir production over an extended period of time and keep it profitable? Solution Multilateral well construction technology has also meaningfully enhanced production. Multilateral technology reduces overall well costs by using advanced drainage architecture to increase the amount of reservoir exposure, thereby improving production and ultimate recovery. By adapting advanced directional and horizontal drilling capabilities, reservoir exposure to the wellbore can be substantially increased, which improves your bottom line by cutting overall development costs. Multilateral wells incorporating intelligent completions & expandable tubulars are just a few of examples of the synergy that will take place in the wells of the future.



Prof. (Dr) Sreepat Jain: Offshore Drilling



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High Completion Cost Challenge Given the high costs of completions in the Lower Tertiary trend, how can I mitigate risk and ensure safety and reliability? Solution Numerous discoveries in the Lower Tertiary have proven that there are plenty of hydrocarbons to be had in these deep rocks, but high completion costs can sideline a project. Frac packing multiple zones in fewer trips can reduce rig time resulting in lower costs, and improve reservoir producibility. When frac packing long, unconsolidated producing intervals, a higher performance tools is needed to reduce completion costs and completion risk. Specialized tools combine the fracture treating and gravel packing processes into a single tool system that requires only one trip into the well, which is essential in the well construction process of these ultra‐deepwater wells. Investing in subsurface modeling can create comprehensive, fit‐for‐purpose pumping and perforation strategies, which can prevent costly problems later in the project. Prof. (Dr) Sreepat Jain: Offshore Drilling



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Increase Recovery Factor



Challenge What techniques can I use to increase production from tight carbonate formations in multi‐zone and multistage completions? Solution Often, wells drilled and completed in low‐permeability formations sustain formation damage, thereby limiting productivity. For increased productivity and improved economics, these wells must be stimulated with acidizing or hydraulic fracturing treatments. Hydraulic fracturing is also needed in wells that have been drilled through layered formations in which vertical permeability is small. The goal of hydraulic fracturing treatments is to improve production for the long term by achieving a high level of conductivity. Multiple zone stimulation also poses unique challenges for completion engineers in vertical, deviated and horizontal wells. Effectively stimulating each pay interval individually can be costly and time‐consuming. Techniques such as limited‐entry and high‐rate fracturing with particulate diversion have, in general, reduced the overall stimulation effectiveness. Prof. (Dr) Sreepat Jain: Offshore Drilling



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Ensure Well Integrity in Reservoirs with High H2S and CO2 Content Challenge How can I ensure the integrity of my well with high H2S and CO2 content in carbonate reservoirs? Solution The pre‐salt carbonate reservoirs found in Brazil's deepwater fields bring significant challenges including a high content of H2S and CO2 due to their complex structures. Since CO2 can adversely affect cementing, any loss of cement‐sheath integrity has to be addressed up front, which requires more than merely designing a typical cement job. Halliburton delivers engineered zonal isolation solutions with a comprehensive approach to achieving reliability in the annular seal for the life of the well and the project from planning to abandonment to post closure. Fit‐for‐purpose solutions allow each cement system to be designed specifically for any given set of wellbore conditions, including blends that are designed to minimize the carbonation effect in CO2 wells. Environmental sustainability requires a re‐evaluation of the cement sheath's role and how it provides a tremendous contribution toward helping increase the life of the well which, in turn, minimizes the impact on the environment. Prof. (Dr) Sreepat Jain: Offshore Drilling



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Ensure Well Integrity in Reservoirs with High H2S and CO2 Content Challenge How can I ensure the integrity of my well with high H2S and CO2 content in carbonate reservoirs? Solution The key risks associated with H2S in the production flow stream of a well are the potential hazards to personnel and metal components of the wellbore. To minimize risks associated with H2S, it is important to address the long‐ term sealing integrity of the cemented annulus. This prevents H2S from flowing though pathways created due to a failed cement sheath, and exposing personnel and metal components to its attack.



Prof. (Dr) Sreepat Jain: Offshore Drilling



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Manage Complex Well Trajectories in Development Projects Challenge How can I best plan and drill complex trajectories to hit the most productive reservoir targets? Solution In deepwater waters reaching relatively small targets often requires complex well trajectories. Many development wells are drilled from fixed installations. The resulting well paths require precise wellbore positioning to navigate around existing wells, reach smaller targets and obtain proper trajectories through and around salt bodies. Collaborative well planning software, with 3‐D multidiscipline data visualization, automated planning features and scenario sensitivity analysis can help planners more effectively optimize platforms while creating trajectories to reach multiple targets with a minimum number of wellbores. Rotary‐steerable tools provide smooth wellbore trajectories while azimuthal, deep‐reading LWD sensors help make real‐time adjustments to stay in thin reservoir sections. Prof. (Dr) Sreepat Jain: Offshore Drilling



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Alleviate Environmental Risks Using Synthetic‐based, High‐performance Fluids Challenge How can I ensure the best environmental performance in my drilling fluid choices? Solution Synthetic‐based fluids have helped reduce the risk of severe downhole losses and reduced overall well costs on many deepwater projects while providing an environmentally friendly alternative to oil‐based fluids. One of the most basic functions of drilling fluid – the suspension of solids – has been radically improved, leading to exceptional drilling performance and an unprecedented reduction in mud losses. Clay‐free invert emulsion systems, stable to 350°F, have helped reduce the risk of severe downhole losses and reduced overall well costs on many deepwater projects while providing best available environmental performance. Our high performance fluids have been used by major operators in Brazil’s Campos, Santos and Espirito Santo basins. For these operations, we customized the engineered fluid solutions to maximize wellbore value for our customers, and provided extremely stable viscosities through a wide range of temperatures, high resistance to contaminants, and extremely low equivalent circulating densities (ECD). Prof. (Dr) Sreepat Jain: Offshore Drilling



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