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Offshore Gas Hydrates Empowers Oil and Gas Professionals to Overcome Sophisticated Challenges

By: , Posted on: January 20, 2016

offshore gas hydrates

What motivated you to write this book?

The author’s twenty years of university research into gas hydrates led to interesting determinations. One line of hydrate studies would lead to an unexpected discovery and the follow-up then created new discoveries, etc.  For example, consider one chronological line of our research:  (1) Initial feasibility studies for storing natural gas safely aboveground in gas hydrates for use by electrical utilities           as an economical fuel substitute at peak load, showed that hydrates self-packed symmetrically and rapidly on heat exchanger finned tubes—facilitated by modest parts per million of synthetic anionic surfactants. The hydrates could be stored rapidly and decomposed at will, dependent upon the temperature of heat transfer fluid pumped through the heat exchanger tubing.  (2) Could such synthetic anionic surfactant behavior be a formation factor for vast hydrates being reported in ocean sediments?  After all, microbes proliferate in hydrocarbon environments of the ocean floor typical of hydrate locations.  Pertinent microbial-produced biosurfactants proved to be anionic.  We tested commercial biosurfactants in laboratory samples of packed, porous media to find that small concentrations of biosurfactants greatly catalyzed hydrates under ocean sediment conditions of deep waters. (3) It became evident that the biosurfactants adsorbed by smectite clays (sodium montmorillonite or nontronite) especially catalyzed hydrate formation. (4) Assisted by access to  many core samples from the Gulf of Mexico and the Gas Hydrate Observatory at MC-118, we determined that indigenous microbes could be cultured or their behavior adequately duplicated by commercial samples of surfactin or rhamnolipid. (5) A mechanism was found whereby seafloor microbes gain access to hydrate masses and thrive on the stored carbon while having access to nutrients diffusing through hydrate capillaries. Longevity of the microbes as well as the hydrate mass is affected. (6) In studying microbial access to the hydrate interior, it was found that the cell-walls prevent hydrate formation, yet the biosurfactant excretions promote hydrates. That is, the exothermic heat of hydrate formation is deadly to the cell if hydrates form on or near cell surfaces. The results introduce peptidoglycan of the cells as a new potential hydrate inhibitor for offshore operations.

It seemed imperative to preserve the preceding determinations along with other research tracks. The findings have import to understanding offshore gas hydrates and potential hydrate-gas production.

No other book addresses them directly.

Who is the primary audience for your book?

The primary audience for the book is industry/government working to develop hydrate-gas reservoirs as viable energy sources.  It is important to stress the international nature of the primary audience:  United States, Japan, South Korea, India, Canada, Great Britain, Norway, France, Italy, Germany, Russia, China, Taiwan, Australia and others.

But universities represent a second audience. The involvement of many disciplines is necessary to understand seafloor hydrates, a circumstance best handled by universities of numerous countries.

A third important audience is the general public. To discover during contemporary times an inordinately large energy source of the cleanest-burning fossil fuel as vast accumulations of ice- like natural accumulations in deep water seafloors, stirs the imagination of the general public.

What are the market needs/key challenges the aforementioned audiences face?

INDUSTRY and GOVERNMENT (the primary audience)

Industry endeavors to establish successful field operations for drilling and production of hydrate gas.  This directly involves related corporate research, government funding agencies and research in national laboratories. To accomplish the goal, their challenge is to develop means to produce the world’s most abundant and cleanest-burning fossil fuel (that is, methane from gas hydrates) in an environmentally safe and economical way.  The process to be developed must overcome monumental and complex hurdles. Some technical attributes the process must have are to:  (a) inject and distribute significant thermal energy for hydrate decomposition, (b) prevent hydrate reformation during production, (c) be adaptable to a wide range of hydrate reservoir classifications, including the difficult one where hydrates are contained in many small fractures of fine-grained sediments, (c) preserve the unique ecology of the seafloor surface where hydrates, hydrocarbon seeps, chemosynthetic communities abound, (d) maintain seafloor stability in hydrate zones of continental slopes, and (e) devise storage/transportation-to-shore for produced, remote hydrate gas.

UNIVERSITY (the secondary audience)

Universities provide essential support for the gas hydrate quest through vital research and for the long-term through courses. In each case, a single comprehensive text on offshore gas hydrates is needed to cover many multi-disciplinary topics, which are best addressed in a university setting. An effective text must give an in-depth overview of all aspects of offshore hydrates.

GENERAL PUBLIC (the tertiary audience)

The general public represents an important 3rd party enamored with gas hydrate occurrences and their implications. As one example, The Discovery Channel joined for several days our early scientific cruise at the MC-118 Hydrate Observatory. As a second example, at least one book of fiction in the past decade highlights gas hydrates in the story fabric.  As a third example, some high school chemistry or physics classes have been known on occasion to delve into the gas hydrate topic—to the intense interest of their young classes. To accommodate these and other public interests, the many facets of offshore gas hydrates must be presented as one text in an understandable manner.

Does your book solve needs/challenges of these audiences? How?

This book is the first comprehensive text serving as an important reference for seafloor hydrates. INDUSTRY and GOVERNMENT (the primary audience)

Feasible processes related to conventional and unconventional gas production are reviewed in Offshore Gas Hydrates relative to applicability to a hydrate process. The review covers the process that would use carbon dioxide exchange for occluded methane as a means to stabilize slope integrity, inject the necessary dissociation energy, and serve the dual role of CO2 sequestration. Depressurization in consort with other processes is evaluated.  Hydrate inhibitors are discussed relative to preventing produced gas from reforming hydrates; a new inhibitor effective in laboratory tests is introduced.  Hydrate reservoir classifications are reviewed for ease of hydrate-gas production, evaluating prospective processes for each classification.  Individual chapters address seafloor ecology of the hydrate zone and reservoir stability during production. Results and description of a pilot plant developed to store and transport natural gas is presented as potential means to recover produced gas from remote offshore locations. To support these innovations, state-of-art field tests and computer simulations are reviewed; over 800 references are detailed.

UNIVERSITY (the secondary audience)

Offshore Gas Hydrates is the first comprehensive text serving as an important reference for seafloor hydrates. For the first time, this text explains interactions of microbes with hydrates in seafloor sediments where a synergy of microbes, minerals, and hydrates is presented. The promotion of hydrate formation by biosurfactants is delineated, as well as hydrate inhibition by peptidoglycan of cell walls is introduced.  Case problems of seafloor instabilities caused by gas hydrates are given.  Published data suggesting mud slides over past geologic time that affected climate are discussed. All in all, a unique treatise on all aspects of gas hydrates covering many disciplines is included. This makes the book conducive for graduate level courses, split-level courses, or senior technical elective courses.  Such a comprehensive text is essential for a successful university research program in gas hydrates.

GENERAL PUBLIC (the tertiary audience)

There are intriguing details in Offshore Gas Hydrates of gas hydrates that appeal to general public interest.  For brevity, consider a cursory list of some points. (1) For the first time our discoveries of the role of microbes in hydrate formation, longevity, and dissociation in the extreme seafloor environment are discussed in detail: biosurfactant catalysis of hydrate formation; cell wall inhibition of hydrates to protect the living cell; interactions with smectite clays; mechanism of cells to access occluded hydrate carbon—the element essential for cell metabolism; cell preservation in the protecting confines of hydrate capillaries. (2) The offshore and arctic gas-hydrate provinces in the United States are detailed.  (3) Hydrate-caused seafloor instabilities are discussed with the evidence of their past catastrophic occurrences: Lake Nyos disaster case study; continental slope slides over geologic time instigating large methane emissions and their climate impact.  (4) Links are given in the text of two short films showing laboratory hydrate formation as well as seafloor ecology of a hydrate zone 150 miles offshore..

Estimates of total carbon contained worldwide in seafloor gas hydrates are impressive. (6) Presented are absorbing reviews and interactions of seafloor ecology within gas-hydrate zones.

A case study is presented of a pilot plant developed to safely store and transport natural gas in gas hydrates.  (7) Effects are presented of microbe survival within hydrates of extreme deep ocean sediments and then those findings are related to postulated Martian sub-surface conditions.

What unique features do you think make the book stand out in the market?

The book is the first comprehensive text serving as a needed reference for all aspects of seafloor hydrates. In a single text, one finds state-of-art discussions of the many facets of this intriguing hydrate phenomenon.

Let’s talk a little deeper about the book…We know that hydrates have been successfully exploited offshore Japan, but what do you think are the chances of this same success existing in other places, such as the Gulf of Mexico? How close are we now to achieving this in the U.S., much less in other parts of the world that really need to find a new energy resource?

It is important to realize that we are but a few decades from the discovery of hydrate extent in the world’s oceans.  Laboratory research, computer simulations, and field tests have progressed in that short time.  Field tests were first funded to successfully characterize hydrates and produce small quantities of hydrate gas in the American arctic. The Joint Industry Program (JIP) study of hydrate reservoir characterization, seismic development, and drilling of prospective hydrate reservoirs in the Gulf of Mexico provided invaluable information possible only through substantial funding. Japan advanced the next phase to larger-scale hydrate gas production. This progress has been detailed in Offshore Gas Hydrates.

The progress has been encouraging on many fronts, but there must be additional funding to continue the progress in all phases of exploration, drilling, production, gas transport to shore, gas storage, and seafloor environment protection during production. Most importantly, processes for gas production from different hydrate reservoir classifications must be optimized for economic and safe production.

In offshore United States, the hydrate resource is well documented and characterized.  There, technical prospects for production look good, especially in the Gulf of Mexico. But under current conditions, hydrate processes must be optimized to make production costs competitive with a large domestic supply of conventional gas. This may require substantially more federal funding. In Japan where conventional gas is scarce and the more expensive LNG provides much of the natural gas for fuel, the price barrier is less formidable. In other sections of the world, an important consideration is the development of a process to produce from fine-grained sediments whose hydrate gas may primarily be contained in fractures.

What do you think are the biggest obstacles still preventing operators from exploiting hydrates?

As far as exploiting the hydrate resource for the methane fuel, it has been a relatively brief period since the vast extent of gas hydrates in seafloors was established.  Significant new processing features must be resolved in order to produce the methane economically:  energy input to dissociate hydrates; preventing hydrates from reforming as dissociated gases move to the wellbore; storage and transport of the gas produced from remote location; ecology and mudslide consequences of drilling and production. Seismic techniques need further refining to optimize exploration.

Tremendous strides toward overcoming these obstacles have been made in a relatively short time, but advancements remain necessary to develop valid universal processing. Experience from pilot offshore hydrate productions as well as extensive computer simulations continue to be most helpful. A viable combination of processes and potentially successful innovative processes are discussed in Offshore Gas Hydrates.

Talk about the Mars chapter in this book. Why did you decide to include it in this book for the oil and gas industry to read?

The oil and gas industry produces from reservoirs of increasingly extreme conditions imposed by deeper waters and arctic regions. In these cases hydrate effects often become more severe, impeding drilling and production. Hydrates invade drilling-muds, create rogue elevated pressure pockets inadvertently penetrated by the drill bit, block lines of produced hydrocarbons, and interfere with control of blowouts. As extremities of conditions in offshore or arctic operations extend, gas hydrates encountered may cause consequences unfamiliar to the petroleum engineer while increasing hazardous potential and retarding drilling/production. The chapter in Offshore Gas Hydrates discussing hydrates on Mars is intended to serve as a case study prompting the engineer’s awareness and anticipation of untoward hydrate behavior in unfamiliar and incompletely defined operating environments where hydrate zones exist.  Considering hydrate consequences in an ultimate extreme subsurface emphasizes vigilance.

Give a synopsis of the Mars chapter content.  Is there something new/different in this chapter that elevates it apart from any past literature on the subject?

This author’s research and that of others in academe and industry extend knowledge of gas hydrates in sediments beneath deep ocean waters; field projects supplement basic laboratory information. These new findings relate hydrates to the following:  biosurfactant catalysis, microbe/mineral/hydrate synergies, microbe preservation in hydrate interiors while being accessible to occluded carbon and to diffusing nutrients, microbe safe havens inside gas-hydrate masses protecting them from temperature fluctuations and radiation, promotion of gas hydrates by smectite clays such as nontronite, seafloor craters, and seafloor instabilities.

In journal articles referenced in Chapter 10 of Offshore Gas Hydrates, numerous scientists hypothesize that gas hydrates exist in the subsurface of Mars. The conclusion seems valid. Therefore, it becomes important to relate how hydrate effects newly determined in ocean floor extreme environments could similarly influence otherwise inexplicable Martian features. For example, how do recent hydrate findings relate to the following questions?

Could microbes survive on Mars?

What causes the erosion features emanating from some Martian craters?

What are the sources and mechanisms of periodic methane pulses reported to occur in the Martian atmosphere?

In what forms could large water supplies exist in the subsurface?

If hydrates do exist in the subsurface, what mechanism would decompose them to create attendant high pressures?

Could concentrated brines be associated with subsurface gas hydrates, hydrate decomposition, and subsequent surface erosion?

Chapter 10 relates new findings from offshore hydrate research to the preceding pervasive questions concerning Mars. It is the first published cause and effect due to hydrate behavior proposed for selected Mars phenomena.

JPL/NASA/UofA periodically updates Martian discoveries made by ongoing rovers and orbiters. How do their reports fit the Martian hydrate hypothesis fleshed out in Chapter 10? The reader should find the answer to this question of ongoing interest as the JPL/NASA/UofA reports are released.

There are two videos included in the e-book version of the publication—one taken from the Mississippi Canyon hydrate observatory site and another from a lab test cell on hydrate nucleation, migration, and self-packing.  What value do you think the videos add to the book’s message?

The laboratory video visualizes for the reader nucleation and growth of gas hydrates, stressing an important appreciation of influences small concentrations of anionic surfactants impose on hydrate formation rate and deposition. Hydrate formation is seen to be surprisingly rapid.

Hydrate crystal embryos are seen forming within the water at surfactant nucleation sites and migrating rapidly to stainless-steel cell walls at the water-gas interface, where they adsorb to symmetrically fill the vessel. Upon hydrate decomposition, hydrate-gas bubbles are surrounded by extremely thin surfactant films, maintaining bubble sphericities while exiting through surrounding pressurized gas. The reader understands from the video how a significant process to store and transport natural gas involving gas hydrates could be devised. Moreover, the action presages monumental effects of anionic biosurfactants in bio-active gas hydrate zones—actions that impact gas hydrate occurrences in ocean sediments.

A video of the seafloor beneath 2900+ ft of water in the Gulf of Mexico shows phenomena occurring characteristic of a hydrate zone.  First, note in the video an outcrop of massive gas hydrates extending into the water above fine-grained sediments. The viewer observes ice worms feeding on the protruding hydrate mass. Biofilms near the imbedded worms undulate in the current. Visual evidence suggests a slow conversion to carbonates by anaerobic oxidation of methane (AOM) proceeding within the hydrate capillaries. Tons of carbonates litter the seafloor amidst venting of natural gas, a direct evidence of long-term AOM reactions in near-surface sediments within limits of seawater sulfate and redirected paths of natural gas venting.  Fractures emanate from a salt dome far below to facilitate gas venting; crude oil-stained hydrates are seen in some fractures.  Chemosynthetic communities subsist on the floor.  Fascinating scenes include the submersible’s robotic arm holding a transparent tube through which a stream of venting gas forms snow-like hydrates of specific gravity <1.0. Another sequence shows the robotic arm of the manned submersible retrieving chunks of gas hydrate from the massive outcrop.  The video puts into perspective the complex ecology associated with gas hydrates in sediments of deep water.

The video can be viewed below:

Want to read more? You can purchase your very own copy of the book and save up to 30% discount when you order via the Elsevier Store using code STC215 at checkout.

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