GAS-LIFT AUTOMATION IN UNCONVENTIONAL FIELDS · Gas-lift Automation in Unconventional Fields ... increasingly important for customers working in shale plays. 2 Gas Lift ... an artificial

Gas-lift Automation in Unconventional Fields

©2017 Weatherford International plc. All rights reserved.

Steve Cannon Global Product Line Manager, GHP Automation

May 2017

GAS-LIFT AUTOMATION IN UNCONVENTIONAL FIELDS


©2017 Weatherford International plc. All rights reserved. ©2017 Weatherford International plc. All rights reserved.

1

AGENDA

1 INTRODUCTION

2 THE DECLINE

3 CUSTOMER CHALLENGES

4 THE SYSTEM

5 AUTOMATION vs. OPTIMIZATION

6 GAS LIFT OPTIMIZATION

7 THE ROADMAP FOR SUCCESS

8 SUMMARY

9 Q & A



INTRODUCTION

Traditionally, shale wells are transitioned directly to rod lift once natural flow has stopped or slowed significantly.

However, many operators are now choosing to delay CAPEX by transitioning to gas lift before later converting to rod lift.

For this reason, gas-lift optimization has become increasingly important for customers working in shale plays.

2

Gas Lift Automation Delays CAPEX for Unconventional Production



THE DECLINE

PR

OD

UC

TIO

N

TIME

Early Production

Later Production

Well Prep

Jet Pump

Rod Lift



Gas Lift Rod Lift

Jet Pump

THE DECLINE GAS LIFT “… an artificial lift method whereby external gas is injected into the produced flow stream at some depth in the wellbore. The additional gas augments the formation gas and reduces the flowing bottom hole pressure, thereby increasing the inflow of produced fluids.” Lea, James F., Nickens, Henry V., and Wells, Mike R.; Gas Well Deliquification Second Edition; 2008 Gulf Professional Publishing.

PR

OD

UC

TIO

N

TIME

Early Production

Later Production

Well Prep



GAS LIFT FACTS

The artificial lift method that most closely simulates a naturally flow well.

Gas lift will only produce what the well gives up naturally.

Gas lift is not a positive displacement pump. More injection gas does not mean more production.

Injected gas simply reduces the hydrostatic head of the fluid column—reducing back pressure on the reservoir—to keep the well flowing above its ‘critical velocity’.



Inefficiencies in GL system and/or facility.

Over/under utilization of supply gas and/or compression.

Overcoming deficiencies in source gas or compression for unloading and ramping.

Manual daily inspection and tuning.

Timeliness and inaccuracy of reports.

Others

CUSTOMER CHALLENGES

A good “system” design is critical for optimization to be effective. We can only optimize to what the wellhead and system are capable of producing.



THE GAS LIFT SYSTEM Supply Gas and Compression: High pressure source of injection gas delivered to the wellhead.

‐ Compressor monitoring & control ‐ Meter supply gas ‐ Discharge pressure

Lift Gas Manifold: Metering, control and distribution of the source injection gas to individual wellheads.

‐ Monitor & control of injection rate ‐ Meter gas volumes

Wellhead: Source gas is injected into the annulus, operating a series of gas-lift valves maintaining sufficient differential pressure to move the fluid to the surface.

‐ Operating casing & tubing pressure ‐ Flowing temperature ‐ Flow line pressure



THE GL SYSTEM

Production Separator: Separates gas and liquids produced from the wellhead.

– Produced gas flow meter (SP, DP, T) – Produced liquid flow meter – Produced liquid tank level (water, oil)

Electronic Gas Meters

– Source injection gas meter; buy back gas meter

– Injection gas meter (wellhead and total) – Produced gas meter (wellhead and total) – Sales gas meter



AUTOMATION vs OPTIMIZATION

Automation Optimization

To manage the operation of a system or process with electronic, mechanical, hydraulic or pneumatic technology.

“To operate without manual intervention”

The systematic or continuous control of a system or process to maximize (or minimize) the results.

“To manage to a target or goal”



EXAMPLES

Automation Optimization

Record process values and status Pressures, temperatures, rates, levels… On/off, open/closed, high/low … Control to setpoint PID, open/close, shutdown… Operating sequences, unloading, ramping,

well testing… Detect events and alarms Accumulate values and reporting – Daily production flows & volumes – Runtimes

Allocation of production resources Facility equipment, compression, injection

gas, etc. Managing production Maximize production, minimize costs Sequencing wells for start-up and shutdown

by priority Control process to seek optimum injection

rates Optimize on/off cycles (intermittent GL

control) Modeling Compare theoretical production with actual

and adjust control parameters.



GAS LIFT OPTIMIZATION

GL Wells have few options for optimization solutions.

Most options have little or no intelligence. Typical solutions include: – PID to control injection rate to a

setpoint – Simple timer for on/off injection

Production changes can easily disrupt simple controls.

Unstable Injection Rates

Dramatic Swings in Casing Pressure



GAS LIFT OPTIMIZATION – THE OPTIMUM INJECTION RATE

The well’s performance can be described by a simple curve showing liquids returned versus gas injected.

This curve is typically calculated from the well model and past performance data.

Most often the performance curve is not available in the controller, and/or periodic calculations may be uneconomical to implement.

Too much time spent under- or over- injecting will result in production losses

Oil

(BB

Ls/d

ay)

Gas Injected (MCF/day)

Under Injection

Optimum Injection

Rate

Potentially Large Production Losses

Over Injection



GAS LIFT OPTIMIZATION – THE OPTIMUM INJECTION RATE

With access to real-time production data or current well test, the WellPilot DLQ will make periodic incremental control adjustments moving toward the optimum injection rate.

What about wells with a common source of gas and compression?

‐ A key feature of the controller is its ability to manage multiple wells. Each well is given a priority. Lower priority wells give up supply to support the higher priority wells.

‐ It also has access to many other automation devices to aid in decision-making.

Oil

(BB

Ls/d

ay)

Gas Injected (MCF/day)

Under Injection

Optimum Injection

Rate

Potentially Large Production Losses

Over Injection



GAS LIFT OPTIMIZATION – UNSTABLE INJECTION RATES

Unstable Injection rates due to changes in the well/reservoir performance and/or production facility (e.g. high line pressure).

Automatic Choke Control. The WellPilot DLQ opens/closes the well using a motorized choke valve with a setpoint for how far open the choke should be initially. After the valve is opened, the “Flow Control” module adjusts the position of the valve until it meets a setpoint rate.

Here the square wave (yellow) is the injection rate. Notice how it is self-correcting to the 550 MCF/d target rate.



GAS LIFT OPTIMIZATION – INTERMITTENT INJECTION Production has become less than expected (modeled/designed).

Limited gas supply/compression.

Intermittent control requires periodic analysis of surface line pressure to determine optimum injection rate. – When injection ON-time continues past the fluid slug arrival, the downhole pressure is maintained higher than

necessary, lowering production. – If injection ON-time is too little, production falls dramatically.

The WellPilot DLQ intelligently changes ON-time to changing well and surface conditions. This well had a rising flow line pressure, requiring more lift gas to complete the lift cycle.



Normal Short or Low Velocity

Flow Restriction

Foamy Slugs

Long, Gas Cut

Fast Cycle

Restriction at Separator

GAS LIFT OPTIMIZATION – ANALYZING SLUG ARRIVAL

With intermittent GL, continuing to inject after the slug has arrived consumes more energy than necessary. And increases bottom-hole pressure, causing less production.

Analyzing the slug for arrival and stopping injection reduces cost and increases production.

The WellPilot DLQ’s proprietary control algorithm detects slug arrival and stops injection.

Customer Real Results:

Usage of lift gas is reduced by moving to intermit GL with the ability to optimize beyond the capabilities of on/off timer boxes.

The drop in lift gas being circulated through the sales line causes a production line pressure drop. Increases in production have been observed due to this result.

Downtime in over-stressed compressors has been reduced due to lower gas volumes.



ROADMAP FOR SUCCESS

Step 1 Step 2 Step 3

17

DynaLift™ is a dynamic gas-lift simulation software application used to interactively test and fine-tune gas-lift system designs before going into the well.

WellFlo lets you design, model, optimize and troubleshoot naturally flowing or artificially lifted oil and gas wells.

ReO provides simulation and optimization of production solutions for surface networks from wellhead to the processing plant.

LOWIS™ software provides real-time surveillance, analysis and well service management tools, empowering producers to better organize and standardize their production workflow processes.

CygNet for Production™ is a fully operational SCADA system, the CygNet Enterprise Operations Platform provides the core foundation, built to adhere to common operations practices and reporting requirements.

The WellPilot DLQ delivers remote, real-time control and optimization for one or multiple gas lifted wells. It continuously monitors available injection gas and distributes to wells by priority. Pre-programmed controls for unloading and ramping functions are supported. Through an integrated approach to production automation, the DLQ provides real-time critical measurements, optimization, and control at the wellhead, meter, or production facility.

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SUMMARY

Understand the Challenges – What are the your problems, frustrations and

missed opportunities?

Plan for success – “System” Design is critical (Reservoir, Well

Construction, Facility, Controls and Optimization)

Optimize – Select equipment that will support multiple

scenarios

It’s a Continuous Process – Monitor, Analyze and Adjust

18

Identify, Plan, Execute, and Review



QUESTIONS

Documents

GAS-LIFT AUTOMATION IN UNCONVENTIONAL FIELDS · Gas-lift Automation in Unconventional Fields ... increasingly important for customers working in shale plays. 2 Gas Lift ... an artificial