In natural settings, such as the ocean bottom, when buried organic matter decomposes to methane and dissolves in water, clathrates form at temperatures greater than 277 K (4 C or 39 F). Biogenically produced methane in dissolved water forms hydrates very slowly, because of mass-transfer limitations. Over geologic time, the total enclathrated methane in the oceans has been estimated at 2.1 1016 standard cubic meters (SCM)--twice the energy total of all other fossil fuels on Earth. The amount of hydrated methane in the northern latitude permafrost is relatively small (7.4 1014 SCM), within the error margin of ocean hydrate estimates. Figure 1 shows world hydrate deposits in the deep ocean and permafrost, most of which were determined by indirect evidence such as seismic reflections called bottom simulating reflectors (BSRs).
Hydrates are a possibility in oil/gas exploration, production, transportation, or processing, which involves water and molecules smaller than n-pentane. When small ( 9 Å) nonpolar molecules contact water at ambient temperatures (typically 100 F) and moderate pressures (typically 180 psia), a water crystal form may appear--a clathrate hydrate. These individual polyhedra then combine to form specific crystalline lattices. Such solids can be formed with N2, H2S, CO2, C1, C2, C3, and iso-butane. Larger molecules like n-butane and cyclopentane require the presence of some smaller molecules.
The literature contains several sources that present a description of the energy sources that are available or are expected to be available during the 21st century. Today's energy options include fossil fuels, nuclear energy, solar energy, renewable fuels, and alternative sources. Fossil fuels are the dominant energy source in the modern global economy, but environmental concerns are prompting changes to an energy supply that is clean. Natural gas is a source of relatively clean energy. Oil and gas fields are considered conventional sources of natural gas.
Natural-gas hydrates are ice-like solids that form when free water and natural gas combine at high pressure and low temperature. Detailed reviews of gas-hydrate chemistry, physics, and oilfield engineering are found in Makogon and Sloan. This page focuses on prevention, inhibition, and removal of hydrates in production. Other pages provide more detail on hydrate formation and predicting hydrate formation. Shut-in gas wells are particularly prone to serious hydrate problems, if the well has been producing some water. Subsequent equilibration of the tubular and its contents with cold zones of the rock can lower the temperature into the hydrate-formation region.
CO2 exchange method is one of the extraction techniques that is under development for the production of methane from gas hydrate resources, and the mechanisms and kinetics of the CO2-CH4 exchange process still remain unclear. We model this process with molecular dynamics (MD) simulation to reveal the reaction mechanism, find the optimal operating condition and enhance the conversion rate. The simulations are carried out at three different temperatures to study the impact of temperature on the exchange rate and the kinetics. The production runs are carried out at microsecond level in the NPT ensemble with pressure held at 5 MPa. The simulation results and the associated analysis show that at the investigated conditions, the CO2-CH4 exchange process involves a direct swap of the guest molecules without complete breakage of the water cages. Also, temperature has a significant impact on the kinetics of the process that the increase of temperature from 250K to 270K accelerates the procedure by at least 1.5 times. The reactions mainly occur at the hydrate surface, so that it is critical to enhance the penetration of CO2 into hydrate structures for large scale application of the CO2-CH4 exchange method.
This feature takes a look at the work being done by companies to improve corrosion inhibitor fluids and inhibition techniques for offshore projects. A wide range of corrosive elements and compounds from a variety of crudes has led to a renewed industry focus on corrosion and the effects it has on pipelines and vessels. As the world's supply of crude becomes heavier, many of the world’s oil producers will have to think more carefully about heavy crudes and the challenges they pose for processing, storage, and transportation. Semoga and Kaji fields experienced reservoir souring and suffered a history of calcium-carbonate (CaCO3) -scale cases before a proper scale-inhibition program was implemented. Problems with a free water knockout discovered continued scale issues, leading to investigation of the reasons.
A computational fluid dynamics model is proposed to analyze the effect of hydrate flow in pipelines using multiphase-flow-modeling techniques. The results will identify the cause of pipeline failure, regions of maximum stress in the pipeline, and plastic deformation of the pipeline. The 9th International Conference on Gas Hydrates featured discussions on key advancements in flow assurance, including the concept of risk management and anti-agglomerates being applicable strategies in transient operations. A BP flow assurance manager explains a methodology for determining and mitigating flow assurance risks. A BP flow assurance engineer discusses the shift in hydrate management strategy from complete avoidance to risk mitigation for an offshore dry tree facility.
Oil demand in India has grown rapidly in the past decade due to its rapidly advancing middle class. A national drive to improve environmental pollution is focusing on natural gas as a transitionary energy source due to its lower carbon emissions. Gas hydrate resources in India are huge and potentially represent a global energy game changer if the technologies for production from hydrate reservoirs are techno-economically established. Several initiatives have been undertaken by NGHP in India for gas hydrate exploration in deepwater offshore. Sustained rapid economic growth has made China and India increasingly important in the world economy.
Gas hydrate resources in India are huge and potentially represent a global energy game changer if the technologies for production from hydrate reservoirs are techno-economically established. Several initiatives have been undertaken by NGHP in India for gas hydrate exploration in deepwater offshore. Fabián Vera, Baker Hughes, and Christine Ehlig-Economides, Texas A&M, explain transient well analysis and how it contributes to shale development. It may not matter whether the IOCs or the NOCs are in charge. The work to be done is the same and the same people will likely be doing it.