Horizontal Gravel

7/29/2019 Horizontal Gravel

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HorizontalGravel

Packs


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Outline

Introduction Circulating path in a standard gravel

pack

Some history

Project planning and execution

Limitations of horizontal gravel packs inERD wells

Future challenges


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Introduction Gravel packing is a commonly applied

technique to control formation sandproduction from open-hole oil and gas wells.

In a gravel pack completion, a screen isplaced in the well across the productiveinterval and specially sized, high permeabilitygravel pack sand is mixed in a carrier fluid

and circulated into the well to fill the annularspace between the screen and formation.


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A basic gravel pack circulating path


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Openhole horizontal gravel packing

OHHGP has gained acceptance as a mainstaycompletion technique.

Projected reliability and the potential to achieve

significantly higher sustainable production rateshave been the major drivers for pursuing this typeof completion.

Interval lengths in excess of 2500 feet are now

fairly common, with the current record being6,938 feet in a well completed in the North Seaby the Texaco North Sea UK Company.


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Some history


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The demand of new technology:

Deepwater completions of high volumeproducers (>15,000 BOPD or >70 MMscf/D) inthe GOM with a well life up to 15 years became

a major challenge for the industry. Increased reliability was needed for the

openhole screened completions, and OHHGPwas the answer to the problems experienced.

Some of the difficulties that were encounteredwill be discussed here


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Key issues in project planning and executionopenhole horizontal gravel packs:

Reservoir study

Shale stability study

Formation integrity test Gravel pack sand sizing

Gravel pack screen

Workstring design Well displacement

Fluid loss control


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Issues that can jeopardize performance of

successful OHHGP

Excessive fluid loss

Varying hole geometry that could lead topremature pack termination

Hole stability issues leading to hole collapse

A narrow pressure spread between

bottomhole pressure and fracture gradient


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Limitations of Extended-ReachHorizontal Gravel Packs

The Beta-wave (return gravelwave) placement pressure is the

main factor in determining themaximum length of a horizontalgravel pack.

This pressure is limited by the

requirement to install the gravelpack without exceeding formationfraction pressure.


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Beta-wave Pressure Control


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High Rate Well displacement toremove fluff

Circulating brine at highvelocity provides optimumhole cleaning.

Ensures that drill solids anddynamic filter cake material(fluff) is circulated out.

The remaining filter cake

should be thin andextremely durable.


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Contd

Advancements in tool technologythat allow multiple functions during

a single trip of the workstring. Advances in screen systems that

provide the capability to isolate andpack around shale sections as wellas the capability to place the gravelpack while encountering fluid loss.


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Final comments

In the future, the newly developed expandablescreen systems may also provide an alternativeto horizontal openhole gravel packing.

In a demanding environment such asdeepwater, technology must continue to evolveto meet the need for long term reliability andhigh productivity.

It is difficult to say whether one of thesetechnologies will emerge as the dominanttechnology.

Horizontal Gravel

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