In many of the world’s petroleum provinces, the natural gas produced along with the crude oil (“associated gas”) has relatively little value, especially compared to the oil. In fact, associated gas is frequently seen to be more of a cost contributor to the oil operations than a net revenue generator for the project and in some regions is an environmental problem when operators choose to flare the gas.
And associated gas continues to create development and production challenges for oil producers because:
- Oil operations have been steadily moving into deeper and deeper waters, where pipeline access is unavailable or prohibitively expensive.
- The traditional low-cost means of disposing this gas was to flare it into the atmosphere. However, this option is rapidly becoming an unacceptable practice throughout the world due to environmental issues.
- Other technical solutions, such as re-injection of the gas into subsurface strata, are expensive and oftentimes not possible due to geological limitations or regulatory prohibition.
- Exploration companies need to test new frontier area oil discoveries, oftentimes for up to a year or more, before they invest billions of dollars in development costs. The associated gas produced in these long-term testing programs is highly problematic to the operators.
If such gas can be collected and transported via pipeline to a market, then this option is usually going to be preferred. Examples of this solution for natural gas can be seen in many shallower water and mature oil basins, such as the Gulf of Mexico or the North Sea. However, different solutions are required in newer petroleum regions and the frontier areas of more mature basins, where gas pipeline infrastructure does not exist.
CNG marine transport of associated gas can be a particularly attractive solution for such projects. CNG offers the following features and benefits in this application:
- CNG can be a low-cost solution for associated gas in deep and ultradeep water.
- CNG is a redeployable solution, which is valuable since many of the newer oil developments have shorter production lives. “Fixed asset” solutions, such as expensive non-redeployable subsea pipelines, may not be cost effective over a short project life.
- CNG can target markets located several hundred miles from the oil field and out of the reach of pipelines.
- EnerSea’s CNG systems are well suited to handle rich associated gas and its heavier hydrocarbons.
- CNG can convert associated gas from a net cost feature (and environmental headache) for oil producers into a revenue generator.