Introduction Shell Global Solutions International (SGSI), CDS Engineering and Petroleum Development Oman LLC (PDO) are jointly field testing a new gas/oil/water in-line separation system (ILS) as part of the Smart Facilities Solutions portfolio of technologies. PDO has a requirement to have water injection facilities at the Al Huwaisah South West production site for reservoir support. Since start of production in 1971, the water cut has gradually increased to 85 - 90 % and is expected to increase further. This paper will describe the joint effort of Smart Facilities Solutions and CDS in applying new in-line separator equipment: a degasser, dewaterer, and hydrocyclone. PDO Al Huwaisah Water Injection Project The Al Huwaisah field has been producing since 1971 with current gross production about 45,000 m3/d (see Figure 1). To improve oil recovery water injection (as well as infill drilling and exploitation of undeveloped areas) new facilities are planned. The project is to develop the South West Area by installing a facility to treat the SW production fluid to provide injection quality water for the water injection wells in the SW area. Presently, the SW area has only wells with a Multi-port Selector Valve (MSV) feeding a 12 inch GRE line to Al Huwaisah gathering station. Over the years the water cut has gradually increased to 85+% and is expected to increase further. The facilities will separate water, oil and gas. The compact inline separation system is designed to separate water, oil and gas. The ILS system is described in the next section. Water is locally injected. Gas and oil and any excess water is combined and sent to the central gathering station through an existing 12 inch GRE pipeline with gas and crude exported to Yibal. The compact inline separation system is a joint effort of SGSI and CDS. In-line Separation System The ILS was seen as an important technology, so SGSI went out into the market for competitive tendering based on the specific criterias of the ILS. CDS Engineering was selected as most suitable for the requirements needed for Al Huwaisah SW project. The ILS has many advantages, such as:It replaces the conventional bulk separator and several stages of separation followed by a water polishing unit.It is built to pipe code, instead of vessel codeIt has low capital costIt requires less manufacturing time, so there is a faster project schedule and earlier productionIt is compact, so it requires much less space and weight, which is an advantage for offshore platforms and eventually subsea applications. Figure 2 shows the PFS of the ILS skid, which is composed of a Degasser, Dewaterer, booster pump and hydrocyclone. The ILS is designed for 12,000 m3/d (75,000 bpd) gross liquids and 65,000 m3/d (2.3 MMSCFD) gas. The crude is a light crude of 35 API gravity. The dewatered oil has a target specification of 15 vol% water in oil. The required injected water specification is less than 100 ppmv oil in water. In the Degasser (see Figure 3) a stationary, horizontal swirl element creates centrifugal forces to separate gas from the oil/water mixture. A gas core is formed in the center of the pipe, which is subsequently collected and routed to the vertical scrubber section. Fast action control valves are used to control the system. The Dewaterer uses similar principles as the Degasser to remove the bulk oil from the produced water stream. A small fraction of gas is also removed. The swirl element creates a core of oil, together with a small amount of gas, which is collected and routed to the vertical scrubber section. The produced water, which still contains a small amount of oil, is routed through a pump to a novel design, low pressure drop hydrocyclone for final separation of the oil from the produced water. Also, there is an additional Dewaterer test to be performed, which would process the 15 vol% water in oil stream to make a tighter specification of 5 vol% water in oil.

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