Page 36: of Offshore Engineer Magazine (Nov/Dec 2013)

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APOLLO can be deployed in a wide variety of challenging geologies and conditions.

Photo: Camcon.

effectively in a wide range of well condi- tions and high-volume high pressure/high

Production temperature (HP/HT) wells. Additionally, gas lift can handle abrasive elements such as sand, and gassy and corrosive fuids in deviated wells. Furthermore, SPM and gas lift injection valves allow for a deeper gas injection in the tubing.

It is these characteristics as well as its fexibility with different production rates that make gas lift more suitable to fuctuating well conditions in offshore operations than ESP and rod pumps. For

The digital age: example, Senergy’s Dr. Rick Lemanczyk recently estimated that gas lift enabled felds can lead to a 2-5% increase in feld-wide production.

Gas lift goes modern bottomhole pressure, allowing reservoir

Technology limitations

Gas lift is recognized for liquids to enter the wellbore at higher Despite its growing popularity, gas lift enhancing well stability – but fow rates. also comes with limitations.

it has its drawbacks. Camcon’s

Today, the side pocket mandrel (SPM) Making injection rate changes in SPM- technique in gas lift that makes use of related gas lift, for example, requires digital gas lift has begun feld injection-pressure-operated (IPO) lift wireline interventions. These types of testing onshore Oman, with valves is one of the industry’s most interventions can damage existing infra- widely recognized products structure (if the wire snaps, for example); ofshore installations anticipated.

Gas lift today remains particularly choke the gas supply at the surface; and

How does it difer from traditional effective offshore and in countering well even halt production as a new SPM unit gas lift technology? Camcon’s instability - something which is becom- is installed. ing increasingly prevalent in older felds. SPM tools also have no instrumen- explains.

Ian Anderson

Such instability can result from a tation on board; operators have little number of factors, including water and real-time information on pressures and

The growth in artifcial lift gas breakthrough in the wells; slugging; temperatures at the point of gas injec-

From the North Sea, where operators or increased well pressures. In addition, tion and limited control and fexibility including Statoil look to achieve average as wells and reservoirs age, liquid rates over altering injection rates. In addition, recovery rates of up to 60%, to the United begin to decrease resulting in wells being the fact that these tools are IPO with the

Arab Emirates’ Upper Zakum expansion more sensitive to fow instabilities. SPM functioning at a pre-determined project, to offshore Malaysia, home to In such cases, gas lift can operate annulus gas pressure can lead to severe the world’s biggest enhanced oil recov- restrictions and increase the possibility ery (EOR) project, increasing oil and gas of unstable wells. recovery is one of the offshore industry’s All too often with such limited infor- greatest challenges. mation, monitoring gas lifted wells is

At the center of these developments is confned to a basic approach, focusing artifcial lift. The artifcial lift market’s on wellhead pressure and the occasional growth is so substantial that Markets fuid level or downhole pressure reading and Markets’ 2013 Artifcial Lift Systems rather than consistent real-time data. It

Market Report predicted it would be is this lack of fexibility which requires worth as much as US$16 billion by 2018. operators to make certain assump- tions about the feld conditions and the

Gas lift and its applicability ofshore perceived characteristics of the well at a

While techniques including electrical given time. submersible pumps (ESP) and multiphase Consider, for example, a feld with 50 boosting are more widely known, another offshore wells all using lift gas as the artifcial technology with signifcant appli- preferred artifcial lift technique. How cations offshore is that of gas lift. can the feld operations team optimally

In gas lift, gases such as CO2, natural produce all the wells when they are gas or nitrogen, are injected into the pro- interrelated and interact? Making a duction tubing to reduce the impact of the change to optimize the performance of

The APOLLO Digital gas lift solution. hydrostatic pressure. This action reduces one well might negatively impact the

Photo: Camcon.

November 2013 oedigital.com 38 000_OE1113_ProdOps2_Camcon.indd 38 10/28/13 1:41 AM