A Proposed Simplified Technique for Accurate Measurement and Calculation of Flared Gas Volume for Nigerian Oil fields

In Nigeria, although the regulatory agencies in the oil and gas industry has placed some financial and cost measures to minimize the amount of gas flared by operating companies, some operators and contractors are yet to consistently report the amount of gas flared in their process plants. These shortcomings are partially due to inadequate application of gas flaring technologies owing to large turn down ratios caused by wide variations in operating conditions of temperature, pressure and flow rate. However, gas flaring is by no means a simple measurement process on its own. This is primarily due to the large variations in conditions often found in a flare stack. Measurement difficulty could also arise through the flare type (be it background, normal or blow-down), changes in the flow profile and Reynolds number caused by variation in the physical properties of the gases and errors due to installation effects. In order to fully appreciate the challenges involved in measuring flare gas volume, it is important to first appreciate these varying conditions and the effect they have on measurement.4 From the aforementioned points, it is clear that the accurate measurement of the flared gas is a rigorous and complex process with several challenges to be considered. This paper presents a simple to use, install and operate software, with high level of precision in accuracy for measuring flared gas volume based on PVs (pressure valves) present in process plants. A similar approach has been applied in South Pars gas development projects in Iran; utilizing the design information in PVs datasheet as well as actual plant data for opening percentage values which have been utilized from plant Distributed Control System (DCS) and PIMS PIMS ( Plant Integrated Management System) using excel and visual basic.5 However, in this study, a more robust software program that has the ability to extract data from the plant’s DCS and PIMS server has been developed using Java, correlation used by this software was generated using HYSYS for a particular process plant model in Niger-Delta and Microsoft Excel used to regress this correlation. An iteration time-step of 1440 minutes has been chosen for greater accuracy. Features of this program include flexibility, user friendly, cost-intensive and real-time. Assumptions made during these calculations were stated clearly in this paper.