Correlation between a deficient phase separation process and the presence of hazardous atmospheres in a production facility

The present assessment provides a window of opportunity for the process optimization in a flow station and compressing plant facilities serving a field operated by PDVSA in Western Venezuela. The flow station object of the present assessment handles a daily production of 25MBPD and over 38MMSCF. Crude oil production goes through a separation process before the gas is compressed to be further used in gas lift wells. The gas plant integrates two compressing chains with three compressors each, which increase the gas pressure from 50psi to 2500psi by means of three compression stages. For over 9 years there has been evidence of detonations within the reciprocating compressors body, which has forced their shutdown during evening hours, leading to the decrease of the oil production from associated wells and important risks to the working personnel due to the presence of a flammable atmosphere. PDVSA INTEVEP coordinated environmental and health inspections in the area surrounding the compression plant and flow station, allowing for the delimitation of further process evaluation in order to diagnose the root cause of the compressor detonations. From the inspections, it was possible to identify the causes of the increased flammability in the evening hours, as well as the origin of the gas mixture that enriched the atmosphere surrounding the compression plant. Further process evaluation within the flow station allowed for the identification of uneven flow distribution to separator vessels, as well as underestimated vessels capacity and inadequate instrumentation configuration that originated deficiencies within the separation process causing gas to be carried under towards the liquid handling facilities.