Schoonebeek Heavy-Oil Redevelopment Requires Complex Chemistry Management

Abstract

This article, written by Editorial Manager Adam Wilson, contains highlights of paper SPE 150635, ’Integrated Production Chemistry Management of the Schoonebeek Heavy Oil Redevelopment in the Netherlands: From Project to Startup and Steady State Production,’ by Andrew G. Shepherd, SPE, Stuart Mcgregor, and Ruud Trompert, Nederlandse Aardolie Maatschappij, and Sen Ubbels, Bob van de Gender, SPE, Theo van Ommen, SPE, and Sjoerd van der Knoop, SPE, Champion Technologies. The production chemistry management process undertaken during the design, commissioning, and startup of the Schoonebeek redevelopment faced challenging separation issues, saline water, and a multitude of other process conditions that resulted in a complex application portfolio. Chemical selection was conducted in adherence to health, safety, security, and environment (HSSE) directives and focused on unique produced fluid properties. Since startup, the success of chemical performance has come from the availability of chemical treatment programs and surveillance/sampling plans. So far, no contingency chemicals have been needed at the facilities. Introduction The Schoonebeek oil field was discovered in 1943 and operated until the late 1990s. A number of enhanced oil recovery methods were used in this field, including high- and low-pressure steam-floods, hot waterfloods, and in-situ combustion. The field is now being redeveloped, using low-pressure steam-flood with horizontal wells. Superheated steam, supplied by a combined heat and power (CHP) plant, will be injected into the reservoir through 25 wells adjacent to the production wells in 17 locations. Gross production will be evacuated from the reservoir through 44 horizontal wells in 18 locations using artificial lift pumps, with a casing vapor recovery (CVR) system included to improve the gross lifting capability. Production from each wellsite will be routed through a gross gathering system to the central treating facilities (CTF). The CTF will include the required facilities to separate the oil, water, and associated gas and treat the respective streams to export quality. Production Chemistry Management Compliance toward European chemical regulations (REACH) was one of main drivers for the short-listing of products to be applied in the Schoonebeek redevelopment. Schoonebeek crude oil has a relatively high API weight. Nevertheless, the crude oil is quite acidic, as seen in high total acid number and naphthenic acid values. Most (>90 wt%) of the naphthenic acids are in salt form, which means that they may affect oil/water separation. The crude oil also has very particular wax properties. A high cloud point and pour point indicate that wax precipitation and gelling in the facilities may become a problem during normal operations if not controlled. Furthermore, wax particles contribute to crude oil viscosity and also may affect separation. Fig. 1 presents an overview of the main chemical applications selected for treatment between the wellsites and the CTF and at the CTF itself, together with the main process vessels and streams.