Measuring what matters in oilfields This case study from the Indian oil and gas industry highlights the use of VEGA’s MINITRAC 31 radiation-based sensor for non-contact density measurement of liquids and bulk solids, and the VEGA radiometric multipoint density array (MDA) profiling system for characterising the oil extracted from the Mangala field in the Rajasthan desert.
I ndia's population is nearing 1.4 billion, and as a developing country, its energy needs are increasing. According to UN forecasts based on current economic growth of 5 to 7%, consumption will double from 2020 levels by 2035 to 2040. This has already led to increased domestic production and the expansion of domestic oil refineries. Oil companies face challenges in meeting demand, however, as they extract and refine oil in remote regions under difficult climatic conditions, where resources take many years, even decades, to access. Enhanced oil recovery The oil extraction process often yields a mixture of difficult-to-characterise products due to varying densities and viscosities across differ- ent drilling sites. Conditions at the wellhead, such as pressures, gas content, temperature and contamination, are rarely consistent. This vari- ability affects extraction and processing costs, presenting a significant challenge in improving yields while pursuing discoveries. Enhanced oil recovery (EOR), also known as tertiary recovery, addresses key industry chal- lenges. EOR employs methods such as chemical injection, ultrasound or steam to boost crude oil recovery by up to 20%. Once EOR is implemented, downstream treatment processes can improve. Crude oil first passes through a slug catcher, which separates liquid slugs. At this stage, oil, water and sand are sorted for further processing, using measure- ment technology to optimise efficiency and ensure safety. Cairn Oil & Gas, a subsidiary of Vedanta
Ltd, utilises multi-density arrays (MDAs) made up of vertically arranged radiometric density sensors in its slug catcher to enhance separa- tion efficiency. Here, VEGA’s MINITRAC 31 non-contact sensors monitor density over a vertical range of 0 to 5 000 mm using advanced scintillating-crystal technology to avoid contact with the process medium. This setup enables real-time data transmission to the control centre, ensuring smooth operations at the Rajasthan Field. The Mangala field Large oil reserves are becoming increasingly rare, and the costs of developing and produc- ing them continue to rise. As a result, there is a growing interest in enhancing yield. To this end, Cairn Oil & Gas and Vedanta Ltd. secured a significant area in the Rajasthan desert back in 2002. This remote location lacks water access and transport links, but prior seismic surveys provided encouraging sonic data suggesting the presence of extensive oil deposits beneath the surface. It took another two years and the drilling of 15 expensive exploratory wells before suc - cess finally came in January 2004, when Cairn tapped into the new ‘Mangala’ oil field in the vast North Indian desert. Globally, this discovery turned out to be the most significant oil find of the year, and India’s biggest onshore discovery in 25 years. It wasn’t until five years later, in 2009, that oil extraction finally began. According to India’s Economic Times, the Mangala field has since produced 473 million barrels of crude oil. To put that into perspective, if this oil were transported
in standard-sized freight train cars, the train would wrap around the globe nearly 40 times. Notably, Cairn produces almost 25% of India’s annual crude oil output from this single field. VEGA MDA profiling The oil from this site is unique due to its waxy characteristics, which cause rapid solidification upon surfacing. The pipeline, therefore, which extends about 700 km, is the world's longest heated crude oil pipeline. Before reaching re- fineries, the oil is cleaned at the extraction site to remove water, sand and impurities. Thorough simulations were essential for pipeline construction and designing the slug catcher. Slug catchers manage slug flow, tempo - rarily storing liquids between the pipeline outlet and processing facilities to protect downstream equipment. These slug catchers rely on droplet separators, which can reach capacity quickly if overloaded. To prevent solid contaminants from accumulating, the VEGA MDA density profiling system monitors density data at various heights within the slug catcher. This ensures efficient separation by accurately tracking the movement of the separation and emulsion layers. VEGA’s radiometric system precisely monitors separation layers in the slug catcher, protecting equipment and maintaining crude quality under extreme conditions.
Reduced maintenance The density-measuring system selected by
Left: To prevent solid contaminants from accumulating, the VEGA MDA density profiling system continuously monitors density at multiple heights. Right: Oil yield depends on more than extraction, optimising raw materials before refining boosts efficiency and output.
28 ¦ MechChem Africa • November-December 2025
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