Perpustakaan Digital ITB

Several well integrity failure may arise when the well enters the production phase. This problems resulted in uncontrolled fluid flow both from the production fluid and the fluid from the formation, creating an annulus pressure known as Sustained Casing Pressure (SCP). To maintain the SCP value from damaging the integrity of the well barrier and cause an uncontrolled release of reservoir fluids, the pressure threshold must be established and maintain for each annulus, namely Maximum Allowable Wellhead Operating Pressure (MAWOP). However, not all fields and wells have sufficient data to calculate MAWOP value. Hence, it is important to ascertain an appropriate method to utilize it, depending on the data available. This study will calculate of MAWOP value from three wells in X field with, using four type methods, namely API RP 90-2 Simple Derating Method (SDM), API RP 90-2 Explicit Derating Method (EDM), ISO TS 16530-1 method, and ISO TS 16530-2 method (obsolete). The result of MAWOP determination using each method will be compared each other to evaluate the magnitude of the MAWOP value and the differences. The most optimal MAWOP value determination method will be selected with some consideration from calculation method made before. The comparison between MAWOP value for each method and the most optimal method for every annulus will be performed in this study to establish rule of thumb MAWOP value determination method that can be implemented in general. Additionally, a new trial of comparing the MAWOP value with depth of the annulus will also conducted to establish rule of thumb MAWOP value determination which spesifically can be applied for another wells in X field. The ISO TS 16530-1 method shown a better result in MAWOP determination, as it includes a more comprehensive component calculation than other methods, making it suitable for the availability of complete field data. The rule of thumb generated for determining the MAWOP value both in general and specific for X field shows different trend for each annulus. For A annulus, the MAWOP value obtained using the API RP 90-2 SDM & EDM method is greater than that obtained using the ISO TS 16530-1 method. However, for B annulus, the MAWOP value obtained using the API RP 90-2 SDM & EDM method varies, occasionally being greater or smaller than the ISO TS 16530-1 method. While in C annulus, the MAWOP value obtained using the API RP 90-2 SDM & EDM methods is smaller than the ISO TS 16530-1 method. The magnitude of the difference in values for each method in each annulus will be presented further in this paper.