The ROV, or subsea remotely-operated vehicle, is frequently used in marine operations such as underwater mapping, pipeline inspection and surveillance, sending payload, maintenance and operations on subsea oil and gas equipment such as BOP (blowout preventer) and Christmas tree assembly, which controls the oil/gas/water flow out of the well.
Underwater environments create various challenges for the manufacturers of the vehicle robotics. In addition to structure integrity under high pressure, complex underwater hydrodynamics characteristics due to coupling of motions in 6 degrees of freedom needs to be considered. Continue reading
Terra-firma, rock-solid and concrete are terms that all inspire images of stability. What could be more reassuring than the support of a good solid foundation? The truth of the stability of terra-firma, rock formations and geomechanics in general is not quite as clear cut as it seems.
As engineers everywhere push the limits of speed, power and capability of products we buy every day, there are also awe inspiring feats of engineering that go unseen to most eyes. Engineers working on civil, oil & gas and infrastructure projects that work on huge scales and push technology just as hard. Continue reading
The recent drop in oil prices naturally has produced economic winners and losers, and price speculators and pundits are lining up conventional producers against those behind American-drilled Shale oil. Yet, questions remain about how the world is over-supplied with oil only a few years after we supposedly passed peek oil and survived oil prices topping $140 per barrel. Discounting the anticipated demand softness due to economic activities in Europe and Asia, technology is playing a strong role in finding, producing and using energy across the full range of industrial activities. Continue reading
How can we accurately predict wave impact loads on ships for seakeeping? Some of the important parameters related to ship hull design include ship motions, vertical accelerations, wave impact/slamming loads, and deck wetness. The ABS Guide for Building and Classing High Speed Naval Craft (HSNC 2007) clearly states that slamming impact load is one of the most critical factors for the scantling design of hull structures. Accurate prediction of wave impact loads requires solving three problems. First is the prediction of wave kinematics, second is the prediction of the pressure and viscous forces and the third is the prediction of ship motion during the wave impact. It is possible to simulate all of these problems with ANSYS computational fluid dynamics (CFD) software. Continue reading
3D Computational Domain including Detailed Geometry of a Subsea Manifold
Lowering subsea structures and equipment into the splash zone is a critical part of offshore installation campaigns. In preparation, engineering teams perform many installation analyses to ensure sufficient crane capacity, clearance and accessibility, structural integrity, and equipment/structure stability. Traditional low-fidelity approaches rely on simplified formulations or empirical equations; some consist of model tests to determine wave loads on structures. But these traditional approaches cannot simulate wave-structure interaction nor the dynamic stress and deformation of structure/equipment due to wave slamming. And hence the accuracy is always a key concern. Continue reading
You may have heard about the grounding of an Alaskan oil rig in January, 2013. The 28,000-tonne rig was pushed toward the shore by waves up to 35 feet and winds up to 62 mph, dragging its main towing vessel and a tug behind it. There have been several such oil rig incidents over the past few decades. The below image shows the failure of an another oil rig platform due to extreme wave forces. A huge wave hitting the offshore platform leads to high wave impact loads that can eventually result in significant platform damage and collapse. These incidents can cause fatalities and damages that can cost hundreds of millions of dollars. Continue reading
Developing more efficient water processing units for oil and gas production is becoming an industry focus. Water occurs naturally within oil and gas reserves and can also be introduced as part of enhanced oil and gas recovery process. The water involved in oil and gas production is called produced water and is an undesired by-product in that industry. Both onshore and offshore produced water requires large amounts of pumping energy and the costs for water management and disposal are rising. The problem is greatest for old wells and for offshore production. Exciting new technologies are being developed to address these issues and engineering simulation can help.
In conversations with work colleagues, we often discuss and debate the question, “What constitutes a state-of-the-art simulation tool?” Having worked in the simulation world for 25 years, I say that the time for a “state-of-the-art simulation tool” has passed. I now answer anyone who asks me, “It is not a tool that represents the state of the art but, rather, a methodology.”
There are many tools that simulate various things, and many of them are quite good. For example, I am firmly convinced that ANSYS HFSS represents the gold standard of 3-D computational electromagnetic simulation tools. However, this is simply one tool in a bag of tools used by engineers; individual tools by themselves do not represent the state of the art in simulation.
This week, I attended the American Flame Research Committee’s Combustion Symposium in Houston where I presented a paper on radiation modeling.
Most of the papers presented were about industrial flares. If you live near a process plant, you must have seen these large stacks reaching into the clear blue sky. At the end of these stacks are large flames that can be seen from a distance. For most urban area residents, these flares create a concern about public health and safety especially if there is some black smoke as well in the fireball.