Managing Risk Associated with Novel Gas Development Projects
Authors: Fagan Conn 
Published: October 2008

The current focus on increased demand for natural gas and the need to address the challenge of stranded and associated gas, has resulted in a number of proposed technical solutions, many of which incorporate a significant level of novelty. Almost by definition such solutions will typically not be adequately addressed by existing engineering experience and prescriptive codes and standards. However the risks introduced by these novel solutions will need to be managed. Risk management will involve identifying hazards, assessing the associated risk, evaluating risk control options and employing the knowledge in decision-making.

Currently proposed gas development concepts include floating and gravity-based structures for processing gas (LNG liquefaction, GTL processing), novel concepts for gas transportation (CNG in pipes and composite pressure vessels), and novel concepts for fixed and floating gas receiving terminals. The degree of novelty varies from concept to concept, either in terms of technology never previous used or in an application of existing technology that was not previously anticipated. How a project tackles such novel aspects will be critical for both safety and for the success of the project.

This paper will address the role of verification in managing risk, in light of the lack of comprehensive prescriptive codes, and will discuss various techniques on how to identify and satisfactorily address hazards introduced by novel technology. A method of qualification of novel technology will be described. Finally some specific challenges based on experience with novel gas concepts will be discussed.

Introduction

Increased demand for natural gas as a clean and efficient fuel has increased the need to transport gas from areas of production to areas of consumption. Where practical, pipelines are used, however especially when the gas discovery is remote from markets, transport by sea is the chosen means of bringing the gas to market. For large volumes over long distances LNG is the normally selected option. For smaller volumes over shorter distances CNG concepts may be most appropriate.

The LNG chain requires at one end facilities for liquefaction of the gas (an export terminal) and at the other end facilities for regasifying it (a receiving terminal). The gas is transported by ships designed specifically for that purpose (gas carriers). This in itself is well known technology, and a technology which has an extremely good safety record. However the current trend is to locate these terminals offshore, a trend which is driven by such factors as unavailability of suitable land sites, problems and delays in permitting, public opposition, and security considerations. The challenge of dealing with gas produced in mainly oil production projects and in also monetizing gas from remote (i.e. without access to pipeline infrastructure) fields has encouraged the development of concepts for transportation of gas in a compressed state at temperatures closer to ambient (variation of temperature and pressure, as well as the design of the containment system essentially differentiates the various CNG concepts). One option for CNG is that it be offloaded to offshore gas terminals. This particular option may be favored by security and safety considerations.

In both cases, offshore LNG terminals and CNG transportation, the proposed concepts incorporate significant novel features.