Offshore Production and Flow Assurance

The oil- and gas-production industry has experienced dramatic price swings over the past year. Crude-oil (spot) prices have varied from more than USD 120/bbl to less than USD 40/bbl since the third quarter of 2014. In high-price environments, technology can be developed economically to exploit additional resources. In low-price environments, technology must be deployed selectively to optimize production. New technology may still be developed and applied, but it is likely to be very focused on reducing operating costs; on the other hand, existing technologies may be revisited, to be applied more effectively.

At all times, industry seeks to improve well productivity. Well productivity is critical during low-price cycles; it is directly related to cash flow and to reserves calculations. Major advances in inflow-control-device (ICD) design and installation have occurred over the past few years. These devices generally are used to manage water breakthrough or to improve the production profile across a large interval. The goal is to minimize workover requirements while optimizing hydrocarbon production costs. Paper SPE 171836 discussed results of an extensive study to compare actual well performance to design with ICDs. The study includes results of failure analyses, which showed that material selection is important for a device to reach its design life.

System operation affects field productivity. Slugging flow in subsea flowlines and risers, leading to pressure surges and excessive liquid levels in the first stage separator, is a major contributor to downtime and suboptimal performance in offshore production facilities. Production facilities operate most efficiently when flows are fairly stable. Slug-suppression technology has been applied historically in shallow water and onshore facilities. Paper SPE 170731 described the successful use of active slug-suppression technology in a deepwater facility. This is an example of integrating existing technologies—slug suppression and process-simulation/process-control theory.

The number of subsea wells is continuing to increase. These wells typically are designed to higher standards than onshore or platform wells because interventions are difficult and costly. How ever, lower-cost options are needed in the event that an intervention is required. Paper SPE 173647 described a case study in which a contingency riserless (light) intervention plan was implemented. Although this technology may not be applicable to all subsea well-intervention needs, it demonstrates that lighter (lower-cost) options should be considered on the basis of an engineering assessment.

The oil and gas industry is a cyclical business. Technology progress can be made during the high- or the low-price phase. As engineers, we have the responsibility to identify and apply appropriate technologies throughout all phases of the business cycle. Let us rise to the challenge.

Recommended additional reading

SPE 170780 Autonomous Inflow-Control Valves—Their Modeling and Added Value by Eltazy Eltaher, Heriot-Watt University, et al.

SPE 172776 Integrated Approach to Liquid Management for Deepwater Gasfield Developments by S. Ahmed, BG Group, et al.

OTC 25656 Pipeline Repair Using Epoxy Technology by Kenneth Bryson, Subsea 7, et al.

Sally A. Thomas, SPE, is a principal engineer in production technology at ConocoPhillips. She holds BS and MChE degrees from Oklahoma State University in chemical engineering. Thomas’ entire career has been with Conoco and ConocoPhillips. Early responsibilities focused on produced water; within the research-and-development organization, she conducted process-development and field-demonstration studies for produced-water recycling and enhanced-oil-recovery projects. After Thomas transferred to process engineering, she developed expertise in process and hydraulic simulation both for ongoing-operations optimization and for new projects. Although mostly stationed in the US, Thomas has had international assignments in the UAE, the UK, and Venezuela. She has served in SPE local-section offices; on regional-meetings organizing committees; as a technical-paper reviewer; as chairperson of the SPE Books Committee; and as a member of the SPE Projects, Facilities, and Construction Advisory Committee and the JPT Editorial Committee.

Offshore Production and Flow Assurance

Sally A. Thomas, SPE, Principal Engineer, ConocoPhillips

22 October 2015

Volume: 67 | Issue: 11