Use of a drag-reducing agent (DRA) allowed an Indonesian pipeline system to overcome capacity constraints quickly, bring on stream additional crude production, and shut down some pumping capacity at substantial savings.
Use of DRA also helped operator PT Exspan Nusantara (PTEN) to overcome line capacity limits on the Samboja-Balikpapan pipeline in East Kalimantan, permitting delivery of more crude production from new discoveries at the NKL field and preventing stock buildup at the main oil station at Sangasanga.
The Kaji-Semoga (KS) field, in south Sumatra, Indonesia, began producing in March 1997 from proved reserves of 77 million bbl of oil and peak production forecast at 40,000 bo/d in 1999-2000. To transport KS production to the 125,000-b/d Plaju refinery, field operator PTEN built two pipelines of 4-in. OD each tied to the Tempino-Plaju pipeline and one 8-in. OD pipeline tied to PTEN-owned Jene-KM.3 pipeline with three booster pump stations (Fig. 1).
As developmental drilling continued, reservoir calculations increased proved reserves to 135 million bbl and peak-production forecast to 68,000 bo/d in 2001. Problems clue to limited pipeline capacity became quickly evident. Alternative solutions discussed included developing another pipeline or laying a loop system. Both needed substantial initial investment and time to develop. The loop system, for example, would require about 1.5 years and an initial investment of $12 million to develop.
Another alternative, one that could be applied in a short time and required less initial investment, was the option of using a drag-reducing agent.
The DRA would be applied at Kaji and booster stations along Kaji-KM.3 pipeline (Fig. 2). DRA injection could increase the Kaji-KM.3 pipeline capacity by more than 90% from its baseline capacity while permitting pipeline-operating pressure to remain within allowable range.
DRA application would allow production of KS field to be accelerated, allowing PTEN to benefit from the domestic market obligation free period and the crude price increment with minimum investment and operating cost.
What is DRA?
DRA consists of chemical agents that reduce or minimize frictional pressure loss caused by the turbulence in the pipeline. (1) A DRA does not work in laminar flow regimes because drag reduction occurs by an interaction of the polymer molecules of the DRA with the turbulence formation of the flowing Fluid or hydrocarbon.
DRAs are solutions of poly alpha olefins, high-molecular-weight copolymers, and viscous or non-Newtonian fluids that are based on either hydrocarbon (iso-pentane or kerosine) or water solvent.
Reducing pressure loss allows the pipeline operation to be optimized in several ways, such as increasing flow rate in existing pipeline system while maintaining operating pressure, reducing pipeline operating pressure while maintaining total throughput or flow rate, reducing energy and operating cost by eliminating a pump booster station along the pipeline system, and many other applications.
The first use of a DRA in the oil and gas industry was to reduce the pressure loss during pumping of fluids downhole to fracture tight formations. DRA application for crude oil transportation or pipeline system began …