Subsea Engineering

Course — SUBS 6340: Subsea Processing and Artificial Lift

Printer-friendly versionSend by emailPDF version

Term: 

Usually offered in the Fall Semester.

Description: 

This three-credit-hour course focuses on the evolving field of subsea processing in conjunction with more conventional artificial lift methods such as water injection, and gas lift. Subsea processing systems create artificial lift that delivers the produced oil and gas using mechanical, electrical and chemical means. The course will begin with a description of subsea processing embodiments. A comprehensive review of multiphase, centrifugal and hybrid gas tolerant flow pumps, gas compressors, multiphase separation, bulk water disposal and high voltage electrical power supplies will be covered. Following this introduction the analytical and numerical models used to design subsea processing systems are presented. In particular, low dimension models will be used to enable systems engineering of subsea processing systems. Outcomes from this course will enable engineers to perform an analysis of subsea processing systems for increased hydrocarbon recovery.

Topics Covered: 

Introduction to Subsea Processing Systems: This part of the course details fundamental details about reservoir characterization. Generation, migration and entrapment of hydrocarbons will be reviewed. Instructor will cover concepts such as, porosity, permeability, wettability. Gives an overview of primary recovery mechanisms and reservoir evaluation. Reservoir modeling, management. Inflow performance curve (IPC), vertical lift performance (VLP), drawdown, maximum efficient rate (MER), productivity and injectivity index are key components of this topic. Lecture will conclude with an introduction to the types of oil trapping mechanisms and solutions to maximize the reservoir production.

Hydrocarbon Characterization: Distribution in the reservoir depends upon thermodynamics conditions, rock properties and physical-chemist properties of the reservoir fluid. Instructor will highlight the typical composition of hydrocarbon liquids and gases and phase behavior of pure components and multi-component systems. Phase diagrams and classification of different reservoir types are key components of this unit. Fluid modeling and characterization through well sampling and lab testing will be covered. Lecture will conclude with fluid modeling.

Subsea Pump Fundamentals: This lecture has the objective of understanding the types of pumps used in subsea engineering and boosting applications, the principles of operation of the most commonly used subsea pumps, selection of pumps according to their applications, interpretation of pump curves and pump sizing. A multiphase pump case study will be explained during the class.

Water Injection: With the aim of maintain and/or preventing decline in reservoir pressure, water injection is utilized for subsea processing engineers. Also water flooding is used to displace oil from the reservoir to the production wells using an immiscible drive fluid. This part of the course introduces to water injection and water flooding as solutions to reservoirs with poor aquifer support. Approaches to water flooding schemes and importance of injection water quality. Student will be able to understand how subsea injection schemes can be applied. Water injection case studies and problem solving on pump system issues will be exercised.

Principles of Gas Lift: Gas lift is a form of artificial lift, whereby gas is added to the flow stream coming out of the well. Throughout this class, students will gain a basic understanding of applications, benefits and system issues related to gas lift. Effects of gas lift in an aquifer driven reservoir and low GOR wells will be covered. Estimation of the gas lift rate and injection pressure are key components of this topic. This unit will conclude with an introduction of some flow assurance issued related gas lift. Gas lift case studies and problem solving on subsea gas compression will be exercised.

Subsea Separation Fundamentals: This unit covers sizing methodology for compressors and understanding of how to size a gas lift delivery line. Approaches of typical configuration for gas liquid and liquid/liquid separators and understanding of why subsea separation is performed. Comparison of subsea separation with topside separation. Operational issues related to separators (i.e. foaming, sand, liquid carry over, gas carry under, liquid slugs), principles and challenges associated with the design of subsea separators are covered.  Derivation and application of vertical and horizontal gas/liquid separators and 3 phase separators. A separator case study will be exercised.

Subsea Power Systems: arquitecture and components of subsea power systems. Variable speed drivers, subsea transformers and umbilical will be covered. In addition, subsea distribution equipment, components of subsea power distribution system, subsea motors, and basics of power transmission will be introduced during the lecture.

Course Grading: 

The course grade will be based on homework, project, quizzes and final exam.

Project: 

A final design problem will be assigned by the end of the semester. A feed study for a Subsea Separation and Liquid Boosting System will be assigned to students. The Project will be completed individually by each student. Each student will submit a short, concise written summary of the project. Project will include: separation, pumping and line sizing. Some of the outcomes of the projects are mass balance calculation, separator and vessel sizing, oil and gas line sizing and power system sizing estimation.