Article Archive

Drag Reducer Selection for Oil Pipeline Based Laboratory Experiment (Part 1)


Oil and gas industry is one of the most capital-intensive industry in the world. Each step of oil and gas processing starting from exploration, exploitation, up to abandonment of the field, consumes large amount of capital. Optimization in each step of process is essential to reduce expenditure. In this paper, optimization of fluid flow in pipeline during oil transportation will be observed and studied in order to increase pipeline flow performance.

This paper concentrates on chemical application into pipeline therefore the chemical can increase overall pipeline throughput or decrease energy requirement for oil transportation. These chemicals are called drag reducing agent, which consist of various chemicals such as surfactants, polymers, nanofluids, fibers, etc. During the application of chemical into pipeline flow system, these chemicals are already proven to decrease pump work for constant flow rate or allow pipeline to transport more oil for same amount of pump work. The first application of drag reducer in large scale oil transportation was in Trans Alaskan Pipeline System which cancel

the need to build several pump stations because of the successful application. Since then, more company worldwide started to apply drag reducer to their pipeline system.

Several tedious testing on laboratory should be done to examine the effect of drag reducer to crude oil that will be the subject of application. In this paper, one of the testing method is studied and experimented to select the most effective DRA from several proposed additives. For given pipeline system and crude oil type, the most optimum DRA is DRA A for pipeline section S-R and for section R-P is DRA B. Different type of oil and pipeline geometry will require different chemical drag reducer.

1. Introduction

One of the most important issues in oil and gas transportation is the existence of turbulence flow in pipeline. Turbulence condition can be described as irregular and erratic movement of fluid when nonlinear inertial effect is superior than viscous effect, generally the fluctuated properties are velocity, temperature, and density. Turbulence flow to happen, energy is needed in order of the inertial effect to dominate over viscous effect. Therefore, the existence of turbulence implies great amount of energy lost to form turbulence leaving less energy to support fluid flow. This creates inefficiency in fluid pipeline transformation as the fluid flow could be faster for same energy input or require less energy for same flow rate.

Limiting turbulence formation can increase energy efficiency as well as increase the throughput of pipeline transportation. Because it is not economical to reduce turbulence by lowering flow rate as it limits field productivity, a better way is invented, that is the use of certain chemical called Drag Reduction Agent or DRA. Drag Reduction Agent is a long chain additive with heavy molecular weight. The effect of DRA application is called Drag Reduction which defined as increase of pump ability of fluid due to addition of small amount of additive into the fluid system in the pipeline.

Phenomenon of drag reduction was first observed by British chemist Toms in 1948. Thirty years later the addition of DRA to pipeline system was first applied by Trans Alaskan Pipeline System in July 1st, 1979. This application proved to be successful in increasing pipeline throughput and eliminating the need for additional pump stations. TAPS thus able to operate near to the optimal production rate of Prudhoe Bay of more than 1.5 MMBBL per day. Since then, the application of drag reducing agent have become popular worldwide. However, until today there is no particular DRA developed for every type of crude oil. Before application of DRA to pipeline system, some testing should be conducted to test the compatibility of prospected DRA to fluid flowing inside the pipeline. This paper discusses one of the selection method to obtain best DRA for a certain case using laboratory observation. The DRA is chosen based on criteria such as: increasing oil flow in the pipeline and optimum drag reduction.