A maintenance management system is a tool used for managing and controlling work, materials, and equipment throughout the oil and gas production chain, from offshore platforms to refineries and pumping stations. Many maintenance management systems are becoming computerized, allowing for a central storage location for the majority of the asset information and data. Computerization of the maintenance system allows users to have access from multiple locations and, if properly set up and maintained, provides an effective tool to track activity over the life of the asset. Computerization of the maintenance system also enables linking of the company’s document management system, warehouse inventory system, and procurement and logistics systems, to name just a few. This linking capability empowers the computerized maintenance management system (CMMS) to reach its full potential.
A HAZOP is a team-based process hazard analysis (PHA) method. Its purpose is to identify hazards and operability issues in a process design. HAZOPs are not fun! Maybe that's not a problem, but they also don't achieve what they could and that is a problem.
Why Don't We Learn What We Should From HAZOPs?
HAZOPs are not as effective as they should be for several reasons, including:
- Tunnel Vision - The focus on small nodes obscures the big picture.
- Guideword Excess - Flow, pressure, temperature, and level are not independent.
- HAZOPs are supposed to identify operability issues, but they really don't explicitly address operability.
- Risk assessment in HAZOPs is typically difficult, ambiguous and not repeatable.
- HAZOP reports are difficult to read and are of limited use.
- Most people don't enjoy HAZOPs and that impacts participation.
The GATE Stream-based HAZOP process avoids these pitfalls via some novel modifications to the process.
The commissioning activities for massive, technically complex offshore facilities often requires years of 24/7-project involvement by hundreds of workers. There is an abundance of time and ample opportunity for accidents to happen with the rapid increase in risk exposure.
Although preventing accidents is the responsibility of every individual worker, HSSE (health, safety, security and environmental) systems employing the right methodology, robust management tools and relevant experience are critical to safety during every work process. Although computers and software cannot produce oil or gas directly, they can help a project team make informed, timely decisions.
Achieving the ideal dryness for a subsea natural gas pipeline is a crucial step not only for commissioning of a pipeline, but also for is subsequent integrity management. Attaining the correct dryness level can help inhibit microbiologically influenced corrosion (MIC), hydrates and other issues.
Drying of a pipeline is usually completed in stages that involve one or more of the following techniques: pigging, methanol/glycol swabbing, air drying, vacuum drying and nitrogen packing.
Selection of methods for drying is often driven by economics and time restraints, without sufficient consideration given to operability and corrosion issues.
Leak testing, commonly confused with hydrostatic testing, is a means of verifying the quality of facility construction. Hydrostatic testing uses liquid media under pressure to test the structural integrity of weld joints and piping spools, while leak testing uses gas or service media, at or close to the maximum working pressure of the system, to serve as a final confirmation that the system is “leak tight” and ready for service. Leak testing simulates “live” conditions without actually using hydrocarbons, allowing flange connections to be checked for “tightness”.
In this GATEKEEPER series, we introduced the Ultimate Gain Plot (Figure 1) and the variables dead time (DT), time constant (TC), and controller gain (Kp). These four aspects along with a basic understanding of the control loop to be tuned, are all that is required to develop preliminary tuning parameters. The examples in this GATEKEEPER demonstrate simple tuning rules.
This is part two of the GATEKEEPER series on control systems tuning. To effectively tune a control loop, there needs to be an understanding about the dynamics of the system. The intention of this GATEKEEPER is not to provide a detailed review, but to provide an 80/20 solution.
Effectively tuned control loops provide for more efficient and safer operation. After process startup, there are various techniques available for tuning controllers ranging from trial and error methods to mathematically sophisticated programs. Few options are available for tuning loops prior to startup. Many control systems are started with the manufacturer’s default tuning parameters. This series of GATEKEEPERS will provide methods for using readily available process design data for determining effective tuning parameters before startup.
A great deal of work goes into making operating procedures accurate, but a procedure that is accurately written may be implemented incorrectly.
Studies suggest that humans conducting simple, mundane tasks make an error roughly 1% of the time. Error rates for complex tasks are much higher. Some procedures are more error-prone than others. It is incumbent upon us to write procedures that are not only accurate, but that are likely to be implemented without error.
The airline industry has dramatically decreased the incidence of human error, in part by focusing on development of effective procedures and on instilling a culture in which the procedures are actually used. We can do the same in the oil industry.
It is frequently necessary to displace the contents of a pipeline or umbilical tube (fluid B) with another fluid (fluid A). If we don’t use a pig to separate the liquids, there will be mixing at the interface (axial mixing). The mixing zone requires us to overflush the line to effectively remove fluid B from the line. Below, we address a method of calculating the length of the mixing zone in order to determine the effective overflush requirement for a given pipeline or umbilical tube.
It comes up very often in projects—”Why can’t the construction team do the commissioning”. On smaller projects this may be acceptable with an experienced team and involvement with operations, but for major capital projects it pays to have a dedicated seasoned commissioning team to execute pre-commissioning and commissioning work.
Hydrotesting of pipelines and equipment, including tanks and vessels, is a key part of ensuring that they are fit for purpose depending on factors such as contact time, chemicals used, oxygen and bacteria. This may result in general corrosion, crevice corrosion, pitting corrosion, differential aeration corrosion or microbially induced corrosion (MIC). MIC will take place due to the introduction of bacteria during the hydrotesting and/or parking of equipment. Corrosion caused by any one or combination of these mechanisms may reduce pipeline and equipment service life and in extreme cases make it unfit for purpose.