At oil and gas facilities, safety, environmental sustainability and regulatory compliance are prioritised along with profitability, security and operating efficiencies.
In the oil and gas industry, exploration companies, fabricators, contractors, manufacturers of oil and gas drilling and production equipment, refineries and petrochemical plants make use of a variety of testing technologies to ensure that downtime is minimised, product quality and quantity is upheld and correct, and environmental requirements are satisfied. The industry relies on awide variety of methods and standards to achieve this. While testing and maintaining equipment is essential for effective production and reduced risk in the oil and gas industry, it is regular calibration of the equipment used for testing which helps guard against incorrect measurement.
Inaccuracy can lead to large financial losses at the exploration, production and distribution stages and significantly impact on site safety. With regular calibration, oil and gas operators can ensure the highest degree of measurement accuracy, reducing measurement uncertainties and helping tomaximise profits.
EQUIPMENT TESTING
Equipment breakdowns can be both expensive and hazardous in the oil and gas sector. To keep equipment and system downtime to a minimum, the oil and gas industry relies heavily on testing to ensure optimum asset health and functionality.
Regular testing provides continuous assessment and enables preventative maintenance which help avoid unscheduled downtime and improves the profitability of oil and gas operators. Some of the most common testing methods include ultrasonic testing, magnetic particle inspection, electromagnetic (eddy current) testing, radiography and magnetic flux leakage.
OIL AND GAS METERING
Due to the huge volumes of oil and gas flowing through transmission pipelines internationally, it is vital that what goes into a network and what goes out to customers does not differ. If there are variations, the potential reasons can involve administrative errors; unmetered gas such as fuel consumed by compressor drivers, heaters in pressure reduction stations, and ‘vented’ gas that leaks from equipment; and systematic metering errors, either initial installation or technical failures or related to the longer-term behaviour of metering systems.
By measuring temperature, pipeline pressure and the pressure drop across a restriction in the pipeline, (called an orifice plate) the flow of oil or gas going through the pipe can be measured. Flow measurement is what establishes prices, which is why it is imperative that it is accurately measured. Therefore, technicians routinely calibrate the pressure and temperature transmitters as it ensures that the variables being used to determine the flow are accurate.
PETROLEUM QUALITY TESTING
Petroleum testing involves quality analysis of petroleum products during upstream, midstream, and downstream production processes. Testing for composition, purity, and contaminants are required for seamless production, trading, and distribution, while the analysis of contaminants ensures the performance, prevents equipment corrosion, and assures high quality and purity. Crude oil fractions different crude oil fractions, petroleum feedstock, and finished products need different analytical tools and methods for analysis. Saturated fractions, for example, can often be analysed by a stand-alone gas chromatography (GC) with conventional detectors.
The aromatics fraction, on the other hand, should be analysed using a GC–mass spectrometry due to its highly sensitive and selective detector. Heavier-cut petrochemical products such as resins and asphaltenes have higher boiling and these products can be analysed using liquid chromatography–mass spectrometry. Fuel additives Adding certain additives to fuels can prevent or remedy fuel delivery system problems. As an example, benzene and toluene are gasoline additives that are analysed using GC. The original method uses a thermal conductivity detector (TCD), but a flame ionisation detector (FID) can also be used for automated analysis.
Oil contaminants
Inorganic contaminants can pollute refined fuels and cause serious problems in product quality, corrode equipment, and interfere with the refining process. Trace-level halogens and sulfur contaminants can be measured accurately by combustion ion chromatography. Trace metals can also be routinely analysed by inductively coupled plasma optical emission spectrometry.
Gas testing
Raw natural gas can come from gas wells (natural gas only), condensate wells (natural gas with other heavier and liquid gas condensates), or crude oil well (natural gas dissolved in crude oil). When natural gas is processed it is transformed from raw into pipeline quality natural gas by removing condensates, impurities, and contaminants to meet quality standards set by pipeline transmission and distribution companies. Owners and operators of the transmission and distribution pipelines require natural gas to be within a certain calorific range, dry with very low water content, and free of contaminants at levels that will not damage or erode the pipelines. Different types of contaminants need to be removed from raw natural gas. Common contaminants include gases, helium, hydrogen sulfide, carbon dioxide, nitrogen, oxygen and water vapour, liquid natural gas condensate and crude oil, trace metals such as mercury, and radioactive materials such as radon.
Gas processing
During natural gas processing, a significant amount of testing is required to meet various standards and contracts. Results from this testing determine the economic value of the field, potential end uses and customers, potential processing costs, quality control for plant operations, and finally end user costs for using the gas and liquids. The value of natural gas when purchased is determined by its energy content, which can vary significantly based upon the final composition. GC is typically the analytical technique used to determine the composition of the natural gas and to calculate its energy content.
When comparing with the value of petroleum products, the cost of metering and calibration is comparatively low. It is recommended that the petroleum industry pays attention to what it can gain by having accurate measurements during all stages of an oil and gas project. This can be achieved by usingcost-effective, best industry metering and calibration practices and improving equipment quality.
