Beyond the Limitations of API RP-14E Erosional Velocity -A Field Study for Gas Condensate Wells

Fluid velocity has the potential to cause severe erosion damage to oil and gas production infrastructure. Therefore, erosional velocity governs allowable production rates from existing oil and gas wells. In order to avoid or alleviate damage due to erosion, the American Petroleum Institute Recommended Practice (API RP-14E) recommends a threshold fluid velocity for production tubing and pipelines. This standard utilizes an empirical formula from which erosional velocity can be calculated. However, field and laboratory data have proven that the applied empirical constant, known as C-factor, within the formula is not valid for all conditions. In many cases, according to the API RP-14E standard, erosional velocity is significantly underestimated or overestimated due to insufficient consideration of fluid characteristics. In addition, accurate field data on erosional velocity can assist proper pipe sizing calculations for prospective oilfield projects. Oversizing of tubing unnecessarily increases construction costs whilst underestimating the required size of tubular can lead to catastrophic erosion/corrosion failures. In this study, new values for erosional velocity constant, beyond those suggested by API RP-14E, are proposed based on the experimental data achieved from the sidestream pilot test units. The experimental pilot test units were installed on four different gas condensate production fields in the south of Iran. Electrical resistance (ER) probes were employed to gather online erosion-corrosion data from the pilot units, each of which was in service for about nine months. The results showed that higher C-factors can be safely applied for these gas condensate fields in comparison with those recommended by API RP-14E. Furthermore, it was revealed that the pilot test units exposed to a higher condensate gas ratio (CGR) experienced a greater rate of erosion.