Field Trials Help Boost Processing Capacity of Offshore Facility Above Nameplate Limit

Abstract

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 187129, “Demonstration of Processing-Capacity Enhancement on an Offshore Facility Through Systematic Field Trials,” by Neil Rodrigues, SPE, and Nikhil Joshi, SPE, Anadarko; Ricky L. Jagneaux, Nalco Champion; and Kashyap P. Kapadia, Moulinex Business Services, prepared for the 2017 SPE Annual Technical Conference and Exhibition, San Antonio, Texas, USA, 9–11 October. The paper has not been peer reviewed. The Constitution spar in the Gulf of Mexico has an original nameplate separation capacity of 70,000 BOPD and 200 MMscf/D of gas. Production potential from future developments is expected to exceed this limit. In order to maximize value, a systematic effort is under way to enhance the throughput of the facility. Field tests were performed with the goal of identifying any deficiencies that would inhibit the facility from reaching nameplate capacity and identifying areas of improvement that would allow the facility to process beyond this limit. Facility Processing Overview On the Constitution spar (Fig. 1), unprocessed fluids from the reservoir pass through production trains where bulk oil/gas and oil/water separation takes place. Train 1 consists of high-pressure (HP), intermediate-pressure (IP), and low-pressure (LP) oil separators, and Train 2 consists of HP oil, HP inlet gas, and LP oil separators. In Train 1, the HP and IP oil separators are two-phase vessels designed for gas/liquid separation and the LP oil separator is a three-phase vessel designed for both gas/liquid and oil/water separation. Similarly, in Train 2, the HP oil and HP inlet gas separators are two-phase vessels and the LP oil separator is a three-phase vessel. The oil from the LP oil separators in Trains 1 and 2 is commingled and passes through the treater, which is designed to condition the oil to meet export-oil specifications for Reid vapor pressure and basic sediment and water (BS&W). The water from the LP oil separators in Trains 1 and 2 passes through hydrocyclones and then to a flotation unit, designed to remove any free oil and impurities to maintain overboard-discharge-water specifications. The gas from the production separators is compressed through a three-stage flash gas compressor. It then passes through a dehydration unit that consists of a gas cooler, scrubber, glycol contactor, and glycol-regeneration skid. The purpose of these vessels is to remove any entrained hydrocarbons and water to meet export-gas specifications.