Recent Advances in Oil & Gas Production Engineering Professor Ma, Xianlin Nov. 2016

Professional Experience Instructor Ma, Xianlin Phone: 17719557752 About Me Professor, College of Petroleum Engineering, Xi’an Shiyou University Education Postdoc Stanford University Ph.D. Texas A&M University Ph.D.   Institute of Computing Technology, Chinese Academy of Sciences M.S. China University of Petroleum, Beijing B.S. China University of Geosciences, Wuhan Professional Experience 2008-2015, (Senior) Reservoir Engineering, Chevron, Houston, US 1990-1994, Lecturer, China University of Petroleum, Dongying, China Research Interests Reservoir Simulation and Applications Inverse Modeling and Data Integration Modeling and Scaling-up of Enhanced Oil Recovery Stochastic Reservoir Characterization

Grading System Attendance 10 % Homework 20 % Final Exam 70 %

Course Outline Chapter 1: Introduction Chapter 2: Gas Well Unloading Technologies Chapter 3: Advanced Hydraulic Fracturing Technologies Chapter 4: Horizontal Well Fracturing Chapter 5: Coiled tubing operations and Intelligent Well Chapter 6: Unconventional Oil and Gas Production Chapter 7: Shale Gas Development

International Energy Outlook-1 EIA: Energy Information Administration

International Energy Outlook-2

International Energy Outlook-3

International Energy Outlook-4 OPEC (Organization of the Petroleum Exporting Countries) 

International Energy Outlook-4 Organization for Economic Co-operation and Development (OECD)  Non-OPEC petroleum supply growth is concentrated in five countries

Natural Gas Markets-1

Natural Gas Markets-2

What is Production Engineering? A branch of Petroleum Engineering Deals with hydrocarbon fluid flow from the sand face through wellbore to surface Maximizes production (or injection) of fluids from (or into) wells in a manner that optimizes the economic values of the resource Other branches are : Reservoir Engineering Drilling and Completions Facilities Engineering Operations Engineering

Responsibilities of Production Engineer Work closely with reservoir, facilities, drilling and operations engineers Design workover to change downhole equipment Evaluation of well performance and recommend remedial action Design and complete well stimulation treatments

Production System -1

Production System -2

Production System –Pressure lose

Sources of pressure loss in a production system

Production System –Pressure lose Location

Production engineering-wellbore performance

Wellbore performance-introduction

Wellbore performance-IPR/VLP

Wellbore performance-VLP

Pressure lose: Single phase flow, liquid

Laminar flow vs. Turbulent flow Re < 2000 Transitional flow: 2000 < Re < 4000 Turbulent flow: Re > 4000 Laminar flow a fluid flows in parallel layers, with no disruption between the layers Reynolds (1880s) number:  ρ = density,  v = mean velocity,  d = diameter and µ = viscosity

Pressure lose: Single phase flow, liquid

Pressure lose: Single phase flow, liquid

Pressure lose: Single phase flow, liquid

Pressure lose: Single phase flow, liquid

Two-phase flow

Phase Diagram for hydrocarbon matrix CP: Cricondenbar – a pressure point, above which a liquid can not be vaporized. CT: Cricondentherm – a temperature point, above which a gas can not be condensed. C: Critical Point – a pressure and temperature point, at which two phases become identical

Two-phase, flow regimes

VLP models

Total System analysis-nodal analysis Nodal point

Total System analysis-nodal analysis

VLP curve

Oil & Gas Production System Overall flow system Inflow Performance Vertical Flow performance Horizontal flow performance Surface Choke Performance Multiphase flow Pressure loss

Well Inflow Performance Relationship(IPR)

Well Inflow Performance Relationship(IPR) Well production are related to reservoir driving force by inflow performance relationship Mathematical equation that is designed to describe the flow behavior of fluids varies depending on the reservoir characteristics The primary reservoir characteristics （油藏特性） include: Types of fluids Flow regimes Reservoir flow geometry Number of flowing fluids

Introduction Mathematical relationship that is designed to describe the flow behavior of fluids varies depending on the reservoir characteristics The primary reservoir characteristics include: Types of fluids Flow regimes Reservoir geometry Number of flowing fluids

Types of Fluids The isothermal compressibility coefficient is essentially the controlling factor in identifying the type of the reservoir fluid. Reservoir fluids are classified into three groups: (1) incompressible fluids (2) slightly compressible fluids; (3) compressible fluids.

Volume and density change as a function of pressure for three types of fluids Pressure-volume relationship Fluid density versus pressure for different fluid types

Flow Regimes There are basically three types of flow regimes that must be recognized in order to describe the fluid flow behavior and reservoir pressure distribution as a function of time. These three flow regimes are: (1) Steady state flow（稳定流）; (2) Unsteady state (transient) flow; (3) Pseudosteady(semi-steady) state flow.

Flow Regimes

Flow Geometry The flow geometry may be represented by one of the following flow geometries: radial flow（径向流） linear flow（线性流） spherical and hemispherical flow（球形流和半球形流）

Radial Flow Plane View

Linear Flow

Spherical and Hemispherical Flow Spherical flow due to limited entry. Hemispherical flow in a partially penetrating well

Number of flowing fluids The mathematical expressions that are used to predict the volumetric performance and pressure behavior of a reservoir vary in form and complexity depending upon the number of mobile fluids in the reservoir. There are generally three cases of flowing system: single-phase flow (oil, water, or gas) two-phase flow (oil–water, oil–gas, or gas–water) three-phase flow (oil, water, and gas) The description of fluid flow and subsequent analysis of pressure data becomes more difficult as the number of mobile fluids increases.

SPE unit system q stb/d k mD A ft2 μ cP B bbl/stb p psia l ft Types of fluids: incompressible Flow regimes: steady-state Flow geometry: linear Number of flowing fluids: single-phase q stb/d k mD A ft2 μ cP B bbl/stb p psia l ft SPE unit system

Skin Factor(表皮系数） Types of fluids: incompressible Flow regimes: steady-state Flow geometry: radial Number of flowing fluids: single-phase h   Skin Factor(表皮系数）

Pressure Profile (1) S > 0: damaged zone (mud filtrate, cement slurry, or clay particles to enter the formation) near the wellbore exists, causing permeability kskin < k (2) S<0: kskin > k, This negative factor indicates an improved wellbore condition (acid treatment （酸化处理）or hydraulic fracturing（水力压裂）) (3) S = 0: kskin = k

Productivity Index (PI)   (stb/d/psi)   q = JΔp Direct measure of well potential or ability to produce Well property

IPR Curve qmax: absolute open-flow potential (AOF)

IPR for Single Phase (oil) Vertical well production Steady-state Constant pressure support Pseudosteady-state Closed boundary Unsteady-state Radial diffusivity equation

Example of Steady-state IPR

Example of Steady-state IPR various skin factors

Example of pseudosteady-state IPR

Example of transient IPR Well testing relies on the transient flow

IPR for two-phase flow Vogel correlation AOFP is the absolute open-flow potential of single-phase oil flow.

Wellbore Flow Performance (Vertical Lift Performance, VLP)  Estimating the pressure-rate relationship in the wellbore as the reservoir fluids move to the surface through the tubulars Pressure loss hydrostatic and friction pressure drops Several correlations for wellbore flow performance are used (Beggs and Brill, 1973; Hagedorn and Brown, 1965)

Wellbore Flow Performance Liquid holdup, hydrostatic pressure higher friction pressures

Well Deliverability

Artificial Lift Used to lower the producing bottomhole pressure on the formation to obtain a higher production rate from the well. Most oil wells require artificial lift at some point in the life of the field

Types of Artificial Lift Gas Lift DuraLift PC Pumps HydroLift Hydraulic Pumps Beam pump ESP (Electrical Submersible Pumping)

Summary of Advantages and Disadvantages