What’s new in production

Driving operational performance in oil and gas is a pretty big topic, and it’s also the subject of a white paper from consulting company EY. At 16 pages, the paper is necessarily a high-level overview, with subtopics like “Industry objectives” and “Top business issues” that most anyone in the industry could predict. Still, high-level overviews such as EY’s effort have value.

But, the devil is in the details, as they say. A screed on the importance of operational performance is not forthcoming. Instead, it may be more interesting to get into the weeds, as they also say, and take a look at an arcane but useful process that could help you earn your operational performance driver’s license.

A paper, “Production availability analysis for oil and gas facilities: Concepts and procedure” (Brissaud, et. al., DNV France) scrutinizes the topic, beginning with a core concept:

The expediency of oil and gas exploitation depends on the availability of processing facilities.  “Availability” is standardized as the ability of an item to be in a state to perform a required function, under given conditions, at a given instant of time, or over a time interval, assuming that the required external resources are provided. It is based on time, and a single state (the up state) of an item.

Since oil and gas facilities can be in multiple states (i.e., operate at different production levels), ranging continuously from nil to full production, an up state can be assumed when the actual production is equal to, or greater than, a reference level (e.g. a contracted or a design rate). However, because this availability does not differentiate states where production is slightly or greatly below the reference level, even if the impact on resulting production can be important, it is too restrictive for evaluations of production systems.

Other availability (or “regularity”) measures have then been proposed, notably those discussed by T. Aven, 1987. One measure accepted by the ISO 20815 international standard is production availability—the ratio of production to planned production, or any other reference level, over a period of time. (The latter is volume-based instead of state-based; besides, the resulting measure is not a probability.)

Production availability analysis takes part in the production assurance of oil and gas projects. [Activities are implemented] to achieve and maintain a performance that is at its optimum, in terms of the overall economy and, at the same time, consistent with applicable framework conditions. It is especially suitable for projects with medium-to-high technical risk, and during the first life-cycle phases (feasibility, conceptual design, and engineering). The production availability analyses are then used to:

• Predict production performance, and verify compliance with objectives and requirements (specified in the production assurance program (PAP);
• Identify operational conditions, subsystems and equipment items that are critical, and find measures for performance improvement;
• Compare alternatives, and enable selection/optimization of equipment items, configurations, maintenance actions, and operations, with economic considerations (under project, technical, operational, health, safety, environmental and regulatory constraints).

Production performance analyses should be consistent, and assumptions and reliability data should be traceable (ISO 20815). To fulfill this guidance, a procedure for production availability analysis has to be followed.

The authors present a four-step procedure based on their “…experience in reliability, availability and maintainability (RAM) analyses for oil and gas facilities, and meets the recommendations of the general framework given by the ISO 20815.”

Space prevents reporting the extensive details of this procedure. But the authors set the stage by noting that in the current phase of the project…decisions regarding system design have already been made, and thus the purpose of production availability analysis is not the same. During the feasibility phase, the objective can be to optimize asset development plans by analyzing several alternatives.

During the conceptual design, optimization is usually reduced to two or three alternative field-layout configurations. Finally, during the engineering phase, only a few alternative solutions are still possible, and the production availability analysis is used to verify compliance with requirements, for sparing recommendations and spare parts optimization.

Production performance measure also depends on the project phase and relating objectives. To model more exhaustively the performance of a production system, (volume-based) production availability…is usually preferred [to] (state-based) availability. A “reference level” of production has, therefore, to be defined.

To this end, the design rate (maximum input feed rate that can be treated) is often used in early project phases, as it is usually time-independent, convenient for any part or sub-part of the production chain (independently of other systems), and does not require sales contract or well-production rates to be defined. In more advanced phases of a project, the planned production volume, assuming no downtime, can be preferred, taking the constraints of sales contract (e.g., through the contracted rate) and well-production potentials (e.g., through the actual input feed rate) into account once available.

To avoid time-dependent constraints in the system description and modeling, it is more convenient to reason in terms of design rate during the study basis and model development, and to translate in terms of other reference levels only during the production availability analyses.