Abstract
Wax deposition is one of the major risks that causes a serious threat to pipeline transportation during operation, if not prevented. The remediation actions are usually costly; hence mitigation methods are in place to completely avoid the issues from happening. The wax deposition modelling technique has been accepted as a tool to design and continuously optimize the wax management strategy. Non-Newtonian oil-wax viscosity is an important parameter affecting wax deposition in pipelines. The present and widely used viscosity model assumes exponential behaviour as observed in the emulsion system. In this paper, it is demonstrated that this assumption may not be suitable for Malaysian waxy crude oil applications due to instantaneous change of viscosity below WAT and PPT. This paper focuses on the application of the Pedersen and Ronningsen viscosity model available in the commercial fluid and flow simulators namely PVTsim ®, Multiflash ® and OLGA ® which are widely used by the flow assurance fraternities, and how it will impact wax deposition prediction accuracy specifically when applied to Malaysian waxy crude oils.
ABSTRAK: Pemendapan lilin adalah salah satu risiko utama yang menyebabkan ancaman serius kepada pengangkutan saluran paip semasa operasi jika tidak dicegah. Proses membaiki biasanya memerlukan kos yang tinggi; oleh itu kaedah mitigasi disediakan bagi mengelakkan isu ini daripada berlaku. Teknik model pemendapan lilin telah diterima sebagai alat bagi mereka bentuk dan merupakan strategi optimum pengurusan lilin secara berterusan. Kelikatan minyak-lilin bukan Newton adalah salah satu parameter penting yang mempengaruhi pemendapan lilin dalam saluran paip. Anggaran model kelikatan semasa yang digunakan secara meluas menjangkakan tingkah laku eksponen seperti yang diperhatikan dalam sistem emulsi. Kajian ini menunjukkan bahawa kaedah anggaran mungkin tidak sesuai bagi aplikasi minyak mentah berlilin Malaysia disebabkan oleh perubahan kelikatan serta-merta di bawah WAT dan PPT. Kertas kerja ini memberi tumpuan kepada aplikasi model kelikatan Pedersen dan Ronningsen yang terdapat dalam cecair komersial dan simulator aliran iaitu PVTsim ®, Multiflash ® dan OLGA ® yang digunakan secara meluas oleh persatuan jaminan aliran, dan keberkesanan pada ketepatan anggaran pemendapan lilin khususnya apabila digunakan pada minyak mentah berlilin Malaysia.
Funder
PETRONAS Research Sdn Bhd
Subject
Applied Mathematics,General Engineering,General Chemical Engineering,General Computer Science
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