Estimating Wax Plug Transportation Force in Crude Oil Pipeline Pigging

Abstract

Wax plug growth in pipeline pigging significantly impacts the crude oil transportation, even resulting in a wax blockage accident of pipeline. A pigging facility was constructed to conduct the pigging experiments. A physical model was proposed to illustrate the mechanism of wax plug transportation. Furthermore, a theoretical model was developed to estimate the wax plug transportation force per unit contact area. It is found that the wax plug transportation force per unit contact area is independent of the wax plug length and radius, while correlated to the wax yield stress and the interfacial lubrication coefficient. These predicted correlativities match with the experimental results. Additionally, the experimental results show that the wax plug transportation force per unit contact area is independent of the pig geometry and hardness. With the experimental results, the interfacial lubrication coefficient for wax sample prepared from crude oil and diesel oil were calculated to be 0.0749 and 0.0442, respectively. It is indicated that the extruded diesel oil at the contact surface provides a better lubrication effect for wax plug transportation than the extruded crude oil. Experiments with different pig geometries and hardnesses were performed to verify the modeling results. The cases of two field wax blockage accidents were used for validation. With the results from the developed model, an engineering implication was presented accounting for formation condition of wax blockage and emergency operation scheduling as well as selection of an appropriate pig diameter.

Design of Crystal Growth Dimensionality in Synthetic Wax: The Kinetics of Nonisothermal Crystallization Processes

“…The crystallization of waxes is one of the emerging issues from a sustainable technology perspective in terms of both advantages and disadvantages. In the petroleum industry, the deposition of paraffin wax in crude tanks and pipelines affects flow efficiency at lower temperatures, increasing the demand for energy in transportation . On the other hand, wax crystallization is desired in the development of novel materials for energy storage in the energetics, electronics, and automotive industries. − Moreover, waxes exhibit a strong hydrophobic nature and are commonly used as water repellents, protective layers, and surface modifiers .…”

Study on Plugging Material and Plugging Mechanism of Crude Oil Sand Water Filter Pipe

“…The blockage of the sand filter tubes can cause a reduction in the fluid output of oil well or even lead to the blockage of oil wells [5,6]. In addition, replacing the clogged sand filter pipes carries certain risks, as the pipes can easily fracture or break during replacement, leading to wellbore blockage and abandonment [7,8]. The biological selfcleaning anti-clogging high permeability sand filter tube, which has applied electrocatalytic technology, is a new direction for enhanced oil recovery [9][10][11][12].…”

A Comprehensive Model for Cup Pig Incorporating Deposits Rheology and Pig Deformation

“…The researchers have proposed three pigging terminologies to quantitatively describe the pigging process, namely, wax breaking force, wax plug transportation force, and wax removal efficiency. ,− The wax breaking force is defined as the minimum force required by the pipe pig to break the wax layer. , The wax plug transportation force equals the resistance that prevents the pipe pig from advancing during the wax plug transport. , Both of them are responsible for the fluctuation of pressure drop during pipeline pigging. The wax removal efficiency determines the selection of the subsequent pig interference .…”

“…12,15 The wax plug transportation force equals the resistance that prevents the pipe pig from advancing during the wax plug transport. 14,17 Both of them are responsible for the fluctuation of pressure drop during pipeline pigging. The wax removal efficiency determines the selection of the subsequent pig interference.…”