Cased Hole Sand Exclusion Techniques

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Cased Hole Sand Exclusion Techniques

Agenda
Cased Hole Selection Considerations: GP, HRWP or FP Gravel Packing (GP) High Rate Water Packing (HRWP) Frac Packing (FP) Frac-Pack Design & Execution Calibration Diagnostics, Step Rate, Mini-Frac Post-Job Pressure & Temperature Analysis

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Cased Hole Selection Considerations:
GP, HRWP or FPEvery sand prone field / project has an optimum sandface completion, balancing:
– Risk (longevity) – Production (skin) – Cost (Capex and Opex)

For cased hole completions with mechanical sand exclusion, the modern techniques are:
– GP: Gravel pack – HRWP: High Rate Water Pack – FP: Fracpack
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Cased Hole Selection Considerations:
GP, HRWP or FP

Gravel pack
Brineor gel as the carrier fluid 4-6 bpm Skins 10-50 Sand Management Services

High Rate Water Pack
Brine as a carrier fluid, pump rates at or above frac pressure (8-30 bpm) Skins 5-15

Fracpack
Frac gel 15 to 60 bpm Skins -2 to 10

Cased Hole Selection Considerations:
GP, HRWP or FP Installation cost
– Lowest to highest: Gravel Pack, High Rate Water Pack, Fracpack
• • • Mostly due to thepumping (hhp, proppant volume) With fracpacks, high pressure and rate tools may be required Costs are usually insignificant to the overall completion cost (i.e. gravel pack pumping = $80,000 USD, fracpack = $200,000 USD)

Reliability (frequency of failure)
– Fracpacks have the highest reliability of any cased hole sandface completion type, by an order of magnitude

Selection criteria may bebased on availability (especially for fracpacks)
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Gravel Packing
Gravel Packing Overview
– Usually skid based pumping operations – Gel as a gravel pack carrier fluid • HEC, Xanvis, VES – 4-5 ppa, often batch mixed – Pump rate 4 to 6 bpm – 25 to 50 lbs of gravel per ft of perforations – Often multiple stages (i.e. acid, slurry, acid, slurry, etc.) to pack theperforations – Treated in the squeeze position until all of the perforations are packed and then the tool is shifted to the circulating position to complete the annular pack – Popularity has decreased over the years due to the successes of high rate water packs and fracpacks
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High Rate Water Packing
High Rate Water Packing Overview
– Usually skid based pumping operations, butcan be pumped from a vessel if high pump rates are required – Brine as the carrier fluid – 1 ppa – 50 to 100 lbs of gravel per ft of perforations – Pump rate 8 to 30 bpm, at or above the frac pressure – Treated in the circulating position with partial returns (i.e. 2-3 bpm returns) • This allows for good perforating packing while filling the screen annulus from the bottom to the top.
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Fracpacking
Fracpack Overview
– Usually vessel based pumping operations (a.k.a. frac boat, stimulation vessel), but can be skid based for smaller jobs – Crosslinked borate gel or VES as a carrier fluid (200 – 500 cp at 100 sec1)

– Proppant increased from 1 ppa to 10 ppa during the job – +/- 1000 lbs of proppant per ft of perforations – Pump rate 15 to 60 bpm depending on theinterval length and leakoff – Treated in the circulating position with the annulus closed (i.e. live annulus)
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Frac Boats

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Fracpack Design and Execution
Fracpacks are designed for a TSO (Tip screen out) in order to increase width and thus fracture conductivity Pad (frac gel without proppant) in pumped to create the fracture geometry –Frac gel properties are selected based on BHST, reservoir permeability, friction (for x-linked borate gels, 20-40 lbs/1000 gal is commonly used) Slurry (frac gel with proppant) is followed in order to fill the fracture – Proppant is selected on size and strength Optimum frac length and width are determined from NPV analysis Downhole sand control hardware must be selected to handle the erosion and...