welltec: prolonging production and increasing recovery through regular well interventions

Prolonging Production and Increasing Recovery through Regular Well InterventionsAuthor: Brian K Sidle, Vice President - Corporate Marketing, Welltec

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Introduction

Innovation, efficiency and reliability: no one can argue that these are the keys to lower cost and higher

profitability in today’s oil and gas industry. The economics of every field, especially mature fields, have

to be considered closely. And in many cases, more than 50% of the hydrocarbons remain in place. It’s a

real challenge for operating companies to harvest those resources and manage their reservoirs in this

environment. Fortunately, there are places where the required innovation, efficiency and reliability can

be found to lower cost and increase profitability for the operating companies. But before we get to that

answer there are two main points to be addressed.

Background

Producing wells have problems, no secret. And the older the well, the more likely it is to have problems

or to have more severe problems. Failed valves, stuck sliding sleeve doors, produced sand, fill, scale,

restrictions, and so on. Some wells have a combination of these elements or additional ones not

mentioned. All of them, however, contribute to an ever decreasing performance and subsequently cash

flow position.

Unfortunately, the conventional solutions for addressing these problems likely won’t address the

challenges posed today or else companies’ cost basis would be much better. Is your current approach

innovative, efficient and reliable? If only one or none of these attributes is characteristic of your

remediation plan, likely there is room to increase your profitability through improvements.

Overview

As wells are being designed, a universal design criteria is the capability to keep production flowing as

long as possible without having to intervene in the well. This is why, typically, interventions are only

done when something ‘breaks;’ ie production becomes restricted, or stops or an unwanted production

type begins. But this conventional strategy often forces operators into a position where they must cope

with unnecessary levels of uncertainty, leading to inefficient responses.


Quick example, your car won’t start. There can be many reasons or causes, as partially illustrated in

the fishbone diagram above, under a few main categories. Perhaps you’ve been driving it somewhere

it was never meant to go (Environment cause). Or maybe you’re doing something wrong as you try to

start it, like not applying the clutch (Method cause). Or perhaps something is actually broken (Machine

cause).

Regardless, it requires repair and therefore cost. As Figure 2 indicates, there is a minimum fixed cost

associated with the repair. Even if it’s a lightbulb that can be replaced without a trip to the repair

shop, there is still a cost. And the cost of the repair increases with activity; the longer the asset has

been operated without maintenance, the higher the associated cost to remediate.

Figure 1

Machines

Methods People

Vehicle won’t start

Environment

Materials

Fuel Gauge is Broken Battery is

Dead

Spark PlugsBroken

Starter is Broken

The Gear is in the wrong position

Lack of Training

Cold Climate

Turning Beltis Broken

Out of Fuel

Potential causes of vehicle failure

Engine has Overheated

Lack of Car Maintenance

Figure 2

Total cost ($)

Activity

Minimum fixed

element

Repair cost optimization

Variable element


In some industries, this ‘fix it when it breaks’ approach is completely unacceptable. Who would fly on

an airline that didn’t adhere to a service maintenance schedule for instance? And yet in the oil and gas

industry billions of dollars are invested into putting wells in the ground only to squander the potential

performance of the well and reservoir development through gross inefficiencies. An expensive, highly

complex system of parts idle for days, weeks, rather than operating at optimum performance.

Similar to a vehicle or other expensive asset, regularly performed maintenance will increase the

current performance and extend the overall life of the asset. Operators can prolong production

and achieve the highest ROI possible while simultaneously increasing recovery factor and reservoir

drainage. This is point number one, illustrated by Figure 3.

Back to the car example, it’s sitting idle, unable to do its job. You want it back in operation, with the

best solution at the lowest possible cost. What to do?

If it’s a sports car and it’s been driven off road, through high water several times a week to take a

shortcut to work, perhaps this insight could reduce the uncertainty regarding the possible failure

mechanisms. Likewise, if the car has been in to the shop several times to fix a re-occurring problem,

perhaps it’s obvious what the challenge is again this time.

Figure 3

Natural Decline Curve

OilProduction

Volume

ExtendedDecline Curve

Regular interventions enable higher recovery rates, increased ROI versus a conventional ‘fix it when it breaks’ approach

E-line Interventions

Time


Conversely, however, if the car has been operating for several years and has never had any

maintenance on it, then what? Call a friend? Take it to the local shop? Or does it immediately go off to

the dealership on the back of a tow truck?

Similarly for your ‘broken’ well, what next? Where do you begin with addressing the solution?

Let’s take a look at a somewhat subjective measurement system, Figure 4, which compares some of

the potential options using a scoring system of 1-10 with the higher scores being the best.

Defining efficiency as the ability to quickly mobilize, rig-up, run in and out of the well, rig-down

and demobilize off location, it’s clear that a WO rig is the lowest while slickline and e-line score the

highest.

Reliability is defined as the ability to solve the problem once on location. Here the WO rig scores the

highest as it can generally overcome even the most severe of challenges.

On the definition of innovation, this is the ability to understand what the problem is, adapt to the

challenge and bring the appropriate technology to bear quickly, minimizing downtime and restoring

production as quickly as possible. With real time, surface controllable features enabled by e-line versus

the mechanical solutions offered by the others, it scores the highest in this category, offering a 40%

advantage over the WO rig.

Extra Benefits

While a workover rig has the highest chance of success to rectify the problem, what about the trade-

off on efficiency and innovation? Slickline may be efficient as per our definition, but what is the

confidence level on its reliability and innovation to overcome and fix the unknown challenge? Overall,

e-line stands out as the overall winner for these key elements of success.

Figure 4

Efficiency Reliability Innovation

18Slickline

Coiled Tubing

WO Rig

E-line

18

17

24

8

5

3

8 8 8

10 4

9 4

6 4


Another important factor which has not been addressed or scored, but should be considered as part

of the innovation content is the ability to accomplish the work in the safest, most sustainable and cost

effective way possible. A quick comparison of a CT unit to an e-line crew with regards to some simple

metrics: total footprint, size, number of people, number and weight of lifts, sustainability, complexity

of operations and carbon footprint, demonstrates that there is significant additional value to be

gained from deploying e-line. If a WO rig were to be compared the contrasts become even greater.

When you consider these additional benefits it becomes even more clear that an e-line solution offers

significant advantages, especially if you’ve got the right portfolio of tools. That’s point number two.

Figure 5


Examples

Does this approach work? Irrefutably. Since the 1990’s Welltec’s technology has been put to work

redefining the boundaries of what e-line workovers could accomplish. Not only does this methodology

provide efficient operations, e-line is a proven, reliable method of accessing and addressing wellbore

challenges. And it is also a proven platform for the development and successful introduction of new,

innovative technology.

Trying to future proof wells by installing current technology in them can be a risky proposition since it

remains in the ground indefinitely, unable to be updated. Rather the application of new, appropriate

technology as it develops is the real solution for maximum value. A problem occurs and modern

technology is applied quickly and efficiently, capitalizing on what’s available now and relying on what

was ‘new’ five, ten or twenty years prior.

Perhaps our industry will never get to the stage where point number one of implementing regular

interventions is realized universally, but certainly point number two about applying modern e-line

technology is relevant and applicable immediately. Innovation, efficiency and reliability at your

fingertips to optimize production at a lower cost.

0% 0% 0% 0%

9%

24%

31%

49%55%

63%68%

79%

87% 87%86%88% 90% 92% 92%

93%97%

Figure 6

# o

f in

terv

enti

ons

92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09 10 11 12

Snubbing/ RasCoiled TubingWireline TractorWireline Tractore-line share of total interventions


A few examples to highlight that approach are provided below.

94% TIME SAVINGS, INCREASED SAFETY AND CASH FLOW

Offshore Mexico, subsurface safety valves (SSSV) require periodic function testing to ensure reliable

operation when needed. Typically, they are tested and if they fail, a workover rig is scheduled to shut

in the well and replace them.

A new technique has successfully been implemented which precludes the requirement to shut in the

production or even to mobilize a workover rig. Using the Well Cleaner® Wishbone Honer (WBH), the

operator has been able to repair the valve in-situ with the well flowing.

Analysis determined that often the SSSV failed to close completely due to debris which limited its

ability to hold pressure during the testing. After careful planning, a Well Tractor® and Well Cleaner®

WBH were mobilized and run on e-line to the desired depth. There the WBH was activated and

cleaning of the SSSV and surrounding tubing was performed. Following the cleaning the SSSV was

successfully tested.

The entire operation was completed in only 18 hours compared to ~ one week for the rig operation

to pull the SSSV. And the well remained on production throughout, demonstrating the benefits that

e-line interventions can provide.


PRODUCTION RESTORED, $2MM SAVED

Onshore Nigeria, a retrievable safety valve assembly failed to seat properly in the tubing and flowed

up hole with the production to get stuck somewhere near the tubing hanger; precise position

unknown.

More than 1,000 slickline jar attempts were made to free the fish. Indicators showed that the lock

mandrel fishing neck was partially open, suggesting that its keys were jammed in a slightly inclined

position, below the lower ID of the tubing hanger profile.

Based on this problem description, Welltec® engineered a solution. Using the Well Tractor® and Well

Miller® plus a custom nipple milling bit in combination with the Well Stroker® the team succeeded

in milling out the safety valve which fell to the bottom of the well as desired, restoring access and

production.

This successful milling operation enabled the operator to avoid having to pull the entire completion

string and saved more than $2MM compared to the alternatives. The operator was very pleased to be

able to regain the well in a shorter time frame and estimated that the milling solution was twice as

efficient as the other options.

WELL STROKER® XXS SAVES FIVE DAYS OF RIG TIME AND RECOVERS STUCK TOOL

Baku, Azerbaijan, time and costs were mounting during an operation when a 7” retrievable packer and

the setting tool got stuck at 6,486 ft (1,977 m) preventing the operator from putting this oil producer

on production.

Determined to return the well to production as quickly as possible, the operator called out Welltec’s

new double stroker. Capable of accurately exerting force up to 60,000 lbs, the Well Stroker® XXS

latches the assembly, locks into place and exerts the force directly onto the fish (or sliding sleeve

or plug) with no strain on the e-line or other parts of the toolstring. Surface read-out allows direct

measurement and control of the force downhole.


On the first run the Well Tractor® deployed the Well Stroker® XXS to the fish where it latched and

applied 55,000 lbs to release the stuck setting tool from the plug. Then the entire assembly was pulled

from the well and operations resumed to put the well on production.

Use of Welltec’s e-line solutions enabled the operator to prevent mobilization of a heavy duty coiled

tubing unit, providing a fast, effective solution and saving a minimum of five days rig time as well as

the environmental and cost differences.

90% COST REDUCTION WHILE RESTORING INJECTION ON A LIMITED SPACE PLATFORM

Offshore India, limited crane height, space and daylight operations posed challenges on a small

platform to an operator trying to restore injection on a converted producer.

A thorough risk assessment was conducted and equipment mobilized offshore to rectify the problem.

The first run revealed that the GS profile couldn’t latch onto the lock mandrel completely. A Well

Cleaner® Power Suction Tool (PST) was then run to remove debris which had settled on top of the

lock mandrel. The Well Cleaner® PST uses a venturi system to create a powerful vacuum which

agitates and mobilizes the debris, trapping it inside bailers and removing it from the wellbore.

Once the Well Cleaner® PST was recovered, the Well Stroker® with GS pulling tool was run. It latched

the lock mandrel and with one stroke pulled the reluctant lock mandrel (and attached TTSS) free. The

entire assembly was removed from the well and injection established at 22,000 bwpd.

The operation was carried out in only three days and provided significant savings, approximately 90%,

versus a barge-based, coiled tubing operation.


Innovative, Efficient, Reliable Solutions

Innovation, efficiency and reliability: no one can argue that these are the keys to lower cost and higher

returns in today’s challenging environment. At Welltec, we have the vision and technology to help

improve returns, reduce risks and increase sustainability without increasing your exposure.

Our success is based upon our ability to continuously create truly disruptive innovations, making the

industry safer and more sustainable while achieving higher recovery. Through a unique combination of

patented technology and pioneering approaches, we deliver game-changing value.

Welltec’s customers benefit from increased production and overall recovery rates using a fraction of the

time and energy of conventional methods. Their cash flows have been improved by higher, extended

revenue streams and significantly lower costs. And they can exploit the full value of their reservoirs.

Now is the time. Explore your options.

At Welltec we believe it’s possible to improve the way the industry operates by offering a change in

mindset, a change in technology. We have pioneered and developed robotic tools which safely and

reliably carry out their operations to repair wells through e-line interventions. Restored production,

optimized assets with a safer, more sustainable approach than conventional methods. Yes, it sounds too

good to be true….but it is. www.welltec.com

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