Age of Analytical Multiphase Flow Modeling Multiphase AP

Age of Analytical Multiphase Flow Modeling: Multiphase AP Engine (MAPe) Overview Dr. Anand S. Nagoo www. nagoo-associates. com

Outline • Breakthrough in modeling multiphase flows – new age of analytical prediction Analytical Advances Review • Find optimal lift – reliably predict wellbore downhole pressures (lift performance) Field Use Cases in Practice • Find optimal rate – diagnose horizontal well liquids loading early (artificial lift) Gain Immediate Value MAPe Overview – 2

Key Take Away Analytical advances in multiphase flow modeling now affords reliable downhole predictions for optimizing production and artificial lift in horizontal wells! MAPe Overview – 3

Analytical Multiphase Flow Modeling • Problem Definition: a set of averaged-equations for reliable predictions of field-scale multiphase flows “The formulation of a satisfactory set of averaged-equations models emerges as the single highest priority in the modeling of complex multiphase flows. ” Mathematical Representation Reality Prosperetti and Trygvasson (2007) MAPe Overview – 4

Analytical Multiphase Flow Modeling • Business case: get reliable downhole pressure from available surface field data at low cost (the prize!) - Lift curves for rate transient analysis (RTA), nodal analysis, reservoir simulation, reserves estimation - Faster simulations for real-time well surveillance, downhole monitoring and digital oilfield integration - Downhole gas velocities and virtual flow metering - Eliminate or minimize costs for pressure gauges MAPe Overview – 5

Analytical Multiphase Flow Modeling Pipe Fractional Flow Theory, Nagoo (2013) Mechanistic Multi-field / CMFD / PDE Analytical / Digital Empirical MAPe Overview – 6

Analytical Multiphase Flow Modeling DEEP (KEY) ANALYTICAL INSIGHT: In multiphase flow, what matters are the measurable changes in the velocities and volume fractions. They govern the transport processes of the multiphase flow – the transport of conservation quantities like mass, momentum and energy, i. e. why flow patterns matter! MAPe Overview – 7

Analytical Multiphase Flow Modeling Fractional flow paths interconnect flow patterns in continuous (analytical) ways! CMEM Journal, v. 6, n. 2, pp. 240 -250, 2018 MAPe Overview – 8

Wide Range of Industry Applications • Pipe Fractional Flow Theory validated against world’s largest published multiphase flow database (110+ labs) Demonstrates the need for reliable Non-Newtonian flow predictions, e. g. slurries, heavy oils, drag-reducers, drilling fluids (SPE 163438) UK, Swansea, Wales horizontal air and viscoelastic polymer Non-Newtonian multiphase flow (Chem. Eng. Res. Ind. Journal, v. 62, pp. 22, 1984) US, Shell E&P large-diameter riser transient multiphase flow (OTC 23968) MAPe Overview – 9

Wide Range of Industry Applications High water velocity Low water velocity New obstructed flow capabilities for perforated wellbore, valves, chokes, solid deposits, jet pumps, nozzles (wholly analytical slip ratio for virtual flow metering!) Source: Pilehvari (1980) Source: Pougatch et al. (2008) Canada, British Columbia convergent-divergentconvergent nozzle multiphase flow US, Oklahoma subcritical-to-critical air-water choke multiphase flow MAPe Overview – 10

Wide Range of Industry Applications ESP, PCP and other pump performance curves can be solved simultaneously with wellbore multiphase flow equations to reliably predict downhole pre- and post-pump variables and local flow characteristics US, Permian basin horizontal gas-oil-water well with ESP multiphase flow pump intake pressure (PIP) field data available (installed gauge) for entire horizontal ESP well production history MAPe Overview – 11

Case Study 1 – Reproducing PLT • Delaware basin gascondensate-water well • Horizontal wells are uniquely complex systems • Liquids held up in up-flow and gas held up in downflow - demonstrates strong impact of well trajectory • Extreme slip effects exist as long as up-flow and down-flow exist MAPe Overview – 12

Case Study 1 – Reproducing PLT • Extreme slip effects are not captured in pressure profile • Wellbore pressure, by itself, will not reveal the true picture of downhole conditions – need phase velocities, holdups and critical rate profiles MAPe Overview – 13

Case Study 2 – Reproducing Gauge Blind Test: Downhole gauge simulation vs. measured pressure gauge data for Permian basin gas-oil-water horizontal well MAPe Overview – 14

Horizontal Well Liquid Loading • Business case: early detection of loading pays! Critical Rate Natural Decline Well Flowing Above Critical Rate Time Well Flowing Below Critical Rate Well deviates from its natural decline It is the deferred production that is most costly and most difficult to recover at late-life Source: defopt. com MAPe Overview – 15

Horizontal Well Liquid Loading MAPe Overview – 16

Horizontal Well Liquid Loading • Practical significance: an accurate diagnosis of downhole flow behavior directly impacts production - What is the critical (minimum) rate to lift liquids? - Where in the well is liquids loading happening? - Is well pre-loading, slight-loading, severe-loading? - Can we quantify lost liquids production? - How to remediate for immediate impact? (change casing/tubing, end-of-tubing depth, etc. ) MAPe Overview – 17

Horizontal Well Liquid Loading - Advanced iterative models not practical, adds more unknowns Well-defined lab flow characterizations do not exist in the field (flow structures are unknown!) Source: slb. com/resources/videolistingpage Horizontal large diameter flow - Simpler models not applicable Vertical small diameter flow • Prior art: poor field predictions Source: Imperial College Not so simple as a ‘film’ or a ‘droplet’ even at lab-scale MAPe Overview – 18

Horizontal Well Critical Rate Eqn Strongest effect is diameter! Critical gas velocity Gas density, liquid density Gas-liquid interfacial tension Inclination angle from vertical Hydraulic diameter • Simple and direct (explicit) analytical eqn • Extensive validation in horizontal field wells MAPe Overview – 19

Horizontal Well Liquid Loading • Use Vg, well vs. Vg, crit curves along entire well to: - Effect of diameter (size and optimize fat casing, tubing) - Effect of EOT landing depth - Effect of wellhead pressures (compression, well control) - Effect of lift location and type (plunger, gas, foam) - Quantify lost production (SPE 191772) MAPe Overview – 20

Horizontal Well Liquid Loading MAPe Overview – 21

Case Study 3 – Detectable Loading Casing pressure Tubing pressure • North America Fayetteville dry gas and water toe-down well with different loading stages detectable from surface field data MAPe Overview – 22

Case Study 3 – Detectable Loading scale magnified • North America Fayetteville dry gas and water toe-down well with different loading stages detectable from surface field data • Vg, well vs. Vg, crit profiles correctly diagnose pre-, slight - and severe-loading data Severeloading occurs when both tubing and bend regions load scale magnified MAPe Overview – 23

Case Study 4 – Undetectable Loading Casing pressure Line pressure Days North America Marcellus gas-water horizontal toe-down well MAPe Overview – 24

Case Study 4 – Undetectable Loading RUN X 1 RUN X 2 RUN B RUN X 2 + 4. 5” tubing Casing pressure Line pressure North America Marcellus gas-water horizontal toe-down well MAPe Overview – 25

Case Study 5 – Test & Validate EOT • North America Eagle Ford gas-condensatewater dew point fluid horizontal toe-down well with EOT lowered to avoid loading MAPe Overview – 26

Case Study 5 – Test & Validate EOT • North America Eagle Ford gas-condensatewater dew point fluid horizontal toe-down well with EOT lowered to avoid loading • Vg, well vs. Vg, crit profiles reliably simulate surface field data trends both before and after EOT landing depth lowered MAPe Overview – 27

Case Study 6 – Design & Predict EOT • Liquid loading changes drastically with EOT location Vg, crit, Vg, well Vg, crit, Vg, well Well incl. (degs) Well MD (ft) Vg, crit, Vg, well 0 30 60 90 MAPe Overview – 28

Case Study 7 – Life-of-Well Lift FBHP We can now analytically determine unloading point! FBHP Combine FBHP + Vg, well + Vg, crit lift curves to quantify lost production and optimize life-of-well lift against declining rates MAPe Overview – 29

Case Study 7 – Life-of-Well Lift UK North Sea offshore gas-water deviated well with published PLT field measurements (Lea et al. , 2008) MAPe Overview – 30

Case Study 7 – Life-of-Well Lift UK North Sea offshore gas-water deviated well with published PLT field measurements (Lea et al. , 2008) MAPe Overview – 31

Case Study 7 – Life-of-Well Lift North America Eagle Ford gas-water horizontal well validating the downhole loading proximity metric against field observations MAPe Overview – 32

Case Study 7 – Life-of-Well Lift North America Eagle Ford gas-water horizontal well validating the downhole loading proximity metric against field observations MAPe Overview – 33

Case Study 8 – Remediate Loading A suboptimal liquidsrich horizontal well with liquids loading in ALL regions of the wellbore North America Permian basin gas-oil-water horizontal well: going from loaded to unloaded using velocity string and gas lift MAPe Overview – 34

Case Study 8 – Remediate Loading North America Permian basin gas-oil-water horizontal well: going from loaded to unloaded using velocity string and gas lift MAPe Overview – 35

Case Study 8 – Remediate Loading North America Permian basin gas-oil-water horizontal well: going from loaded to unloaded using velocity string and gas lift MAPe Overview – 36

Conclusions & Take Home Message • New age of analytical multiphase flow prediction • Analytical modeling capability closes lift performance gaps for reliable downhole pressure predictions • Optimal lift + optimal rate (analytical critical rate eqn) = accurate diagnosis of horizontal well loading Analytical advances in multiphase flow modeling now affords reliable downhole predictions for optimizing production and artificial lift in horizontal wells! MAPe Overview – 37

Four Upcoming MAPe Modules In order of development: • Well and pipeline integrity (multiphase erosion, corrosion, thermal) calculations • Cyclical (plunger lift) and single-instance (pigging) fluid displacement calculations • Combine single-branch calculations for fully-implicit integrated networks (multi-laterals, surface grids) • Solid deposits (flow assurance) and 4 -phase flows MAPe Overview – 38

Contact us at info@nagoo-associates. com for arranging an on-site presentation/demo or training session on the MAPe simulator!