Wax and Asphaltene Deposition Tendency of Malaysian Crude Oils

Abstract

Flow assurance is a term generally used to describe the processes that may lead to fluid flow restriction in production, processing and transportation systems, and also the comprehensive management of the processes and operations to ensure effective and efficient production and delivery of oil and gas from the reservoir to the refinery. Often, the flow assurance issues are largely associated with hydrates, organic waxes and asphaltenes deposition due to changes in fluid composition, pressure and temperature conditions. Organic wax starts to precipitate from oil when temperature falls below the cloud point. The focus of this research is to characterize Malaysian crude oils from Dulang, Tapis, Miri, Dubai, and Arab fields to evaluate their tendency to precipitate wax and/or asphaltene. The oils were characterized by conducting SARA analysis with high-performance liquid chromatography (HPLC), while carbon distribution of the oils was determined by gas chromatography mass spectrometry (GC-MS). Differential scanning calorimetry (DSC) and density meter were used to measure the WAT of waxy oils and the colloidal instability index (CII) was calculated to evaluate asphaltene deposition potential. The effect of continuous carbon dioxide (CO 2 ) injection on WAT was also investigated. Results show that crude oils with higher paraffinic content exhibit higher WAT and precipitated wax. Continuous gas injection was found to lower the WAT, thus reducing the risk of wax precipitation. Tapis oil with highest CII (5.05) is the most susceptible to asphaltenes deposition, while Arab oil with CII of 1.21 has the least tendency to cause asphaltenes deposition problems.

The rheological behavior of crude oil in the presence of palm oil additives

“…Besides, other esters of oleic acids such as stearic acid and linoleic acid may form strong H-bonds with resin where the mutual overlapping aromatic ring planes of oleate-resin is greatly reduced which in turns reduces the crude oil's viscosity significantly (Akinyemi et al 2018;Soni et al 2005;Taiwo et al 2012). Based on Table 1, CPO contains the highest percentage of oleic acid followed by CPKO.…”

“…Among the flow assurance issue, the precipitation of wax inside the tubing and the pipeline during the production of crude oil is a major challenge. In tropical waters such as Malaysia, the average seabed temperature ranges from 4 °C to 7 °C which often leads to wax precipitation as the crude oil drops below the wax appearance temperature and later the deposition of wax onto the pipe wall due to molecular diffusion (Sulaimon and Yusoff 2014). The deposition of wax onto the pipe wall causes the decrease in the tubing inner diameter, therefore requiring higher pressure to transport the crude oil through the pipeline.…”

Non-Newtonian Viscosity Behaviour Investigation for Malaysian Waxy Crude Oils and Impact to Wax Deposition Modelling

“…Santos et al, [20] summarized a few findings from various researchers highlighting the impact of asphaltene concentration on the viscosity, which shows that viscosity can increased sharply with the presence of higher asphaltene content. Malaysian crude oil however, showcased a very low asphaltene content as reported by Sulaimon and Yusoff [8] ranging from 0.13-0.34 wt% which is hypothesized may not have impacted viscosity measurement greatly. It is however a good practice to conduct SARA analysis as part of fluid property screening to determine asphaltene content prior to conducting a more detailed analysis such as dynamic viscosity measurement.…”

Development of Paraffin Deposition Inhibitors in the Producing Oil Field Facilities

“…왁스 고형물은 노말 파라핀(normal paraffin)으로 주로 구성된 거정질(macrocrystalline) 왁스와 이소 파라핀(iso paraffin)과 사이클로 파라핀(cyclo paraffin) 으로 구성된 미정질(microcrystalline) 왁스로 분류할 수 있다 (Nehiem et al, 2006). 노말 파라핀은 사슬형(chain shape) 구조로 미정질 왁스보다 온도 변화에 더 민감하다 (Sulaimon and Yusoff, 2015). 이러한 파라핀 침적 원인요소를 고려하 여 억제효과가 높은 성분들을 조합함으로써 맞춤형 화학제 를 개발하였다.…”