Abstract

Kaji-Semoga ("KS") field, located in south Sumatera, Indonesia, began to produce in March 1997, with 77MMBO proven reserves and peak production forecast at 40 MBO/d in year 1999–2000. To transport the production of KS field to Plaju refinery, PT Exspan Nusantara ("EXSPAN") built a two- pipeline system comprising 2×4-in diameter pipelines tied up to Tempino-Plaju pipeline, and one 8-in diameter pipeline tied up to EXSPAN owned Jene-Km 3 pipeline, with three booster pump stations built along this pipeline.

As the development drilling continued, the reservoir calculation of proven reserves increased to 135 MMBO and the peak production forecast increased to 68 MBO/d in year 2001. Problems arose due to the limited pipeline capacity. To solve these problems, some alternatives were discussed, such as developing other pipelines or a loop line system.

Both alternatives needed substantial initial investment and time to be developed. For example, approximately 1.5 years and an initial investment of $12 million were needed to develop a loop line system. One alternative, which can be applied in a short time and does not require a high initial investment, was suggested. The option called for the use of Drag Reducing Agents ("DRA").

DRA is a chemical agent used to optimize the pipeline capacity by reducing drag and lowering the pressure drop across the pipeline. The DRA was applied at Kaji and booster stations along Kaji-KM.3 pipeline. With DRA injection, we could increase the Kaji-KM.3 pipeline capacity by more than 90% from its baseline capacity, whilst maintaining the pipeline operating pressure within an allowable range.

With DRA application, production from KS field could be accelerated, allowing EXSPAN to benefit from the Domestic Market Obligation (DMO) free period incentive and the crude price increment, with minimum investment and operating costs. Within 1.5 years (estimated time required to develop a loop line) EXSPAN had a net share increment of about $22 million and saved about $0.7 million per year from shutting down one of three booster pump stations along Kaji-KM.3 pipeline. And within the same period of time, the government of Indonesia had a net share increment of about $126 million.

Introduction

Drag Reducing Agents ("DRA") or Drag Reducers ("DR") are chemical agents used to reduce or minimize the frictional pressure loss caused by turbulence in the pipeline. A drag reducer does not work in laminar flow regimes. This is because drag reduction occurs by an interaction of the polymer molecules of the drag reducer with the turbulence formation of the flowing fluid or hydrocarbon.

DRAs are solutions of poly alpha olefins, high molecular weight copolymers, viscous or non-Newtonian fluids that are based on either hydrocarbon (isopentane or kerosene) or water solvent. By reducing pressure loss, we can optimize pipeline operation in several ways, such as increasing flow rate in the existing pipeline system whilst maintaining the operating pressure, reducing pipeline operating pressure whilst maintaining total throughput or flow rate, reducing energy and operating costs 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. Drag reducer application for crude oil transportation or pipeline system began around 1978 and the first injection was into the Trans- Alaska pipeline systems. DRAs used presently in oil and products pipelines are themselves hydrocarbons and thus have no effect on refining process or refined products. Crude oil treated with DRAs on the Trans- Alaska pipeline systems have been refined without incident. Similarly, crude oil from the Kaji-Semoga field at South Sumatera, which is transported through the Kaji-KM.3 pipeline system treated with a drag reducer, has been refined without any incidents.

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