Selection of Diverters
Diverting materials are available for use in varied well conditions and over a wide temperature range. Selection of the best agent and concentration is based on the formation fluids contacted, interval length, formation temperature, physical properties of the formation, type of well completion, and placement. Guidelines for the use of the more common temporary diverting agents are listed as follows:
1. Graded Rock Salth
| – Melting Point: 1,472 ºF | ||
| – Soluble in: water or dilute acid | ||
| – Specific Gravity: 2.164 | ||
| – Type Well: Oil, Gas, Injection, Disposal | ||
| – Type Diversion: On perforations | ||
| On slots | ||
| In perforations | ||
| On formation | ||
| Concentrations to Divert: | ||
| – On Perforations (3/8′′ perforations) 16 lb at 1 lb/gal, 9 lb at 1 1/2 lb/gal | ||
| – In Perforations (per perf.): 1/2 to 2 lb | ||
| – Open Hole (lbft2 of Formation): 5 lb |
2. Oil Soluble Resin
| – Melting Point -328 ºF | ||
| – Soluble in: oil or distillate | ||
| – Specific Gravity: 1.062 | ||
| – Type Well: Oil, Gasb | ||
| – Type Diversion: On slots | ||
| In perforations | ||
| On formation | ||
| Concentrations to Divert: | ||
| – On Perforations (3/8′′ perforations): 2 lb at 2 lb/galf | ||
| – In Perforations (per perf.): 1/8 to 1 lb | ||
| – Open Hole (lb/ft2 of Formation): 2.5 lb |
3. Oil Soluble Resin in Salt Solution
| Melting Point – 328 ºF | ||
| – Soluble in: oil or distillate | ||
| – Specific Gravity: 1.062 | ||
| – Type Well: Oil, Gasb | ||
| – Type Diversion: Through gravel pack | ||
| On formation | ||
| In perforations | ||
| Concentrations to Divert: | ||
| – In Perforations (per perf.): 1/2 to 2.5 gal fluid containing 0.5% | ||
–Open Hole(lb/ft2 of Formation):  |
4. Karaya gum
| – Melting Point – None | ||
| – Soluble in: water | ||
| – Specific Gravity: 1.062 | ||
| – Type Well: Injection, Disposal | ||
| – Type Diversion: On formation | ||
| In perforations | ||
| Concentrations to Divert: | ||
| – In Perforations (per perf.): 1/4 to 1 lb | ||
| – Open Hole(lbft2 of Formation): |
5. Graded Benzoic Acid
| – Melting Point – 252 ºF | ||
| – Soluble in: Oil, water,acid ,gas | ||
| – Specific Gravity: 1.316 | ||
| – Type Well: Oil, Gasi, Injection, Disposal | ||
| – Type Diversion: On perforations | ||
| On Slots | ||
| In perforations | ||
| On formation | ||
| Concentrations to Divert: | ||
| -On Perforations (3/8′′ perforations) | ||
| 9 lb at 1/2 lb/gal, and 2 lb at 1 lb/ft f | ||
| – In Perforations (per perf.): 1/4 to 1 lb | ||
| – Open Hole (lb/ft2 of Formation): 2.5 lb |
6. Benzoic Acid in Alcohol Solution
| -Melting Point – 252 ºF | ||
| –Soluble in: Oil, water, gas, acid | ||
| –Specific Gravity: 1.316 | ||
| –Type Well: Oil, Gas, Injection,Disposal | ||
| –Type Diversion: Through gravel pack | ||
| On formation d | ||
| In perforations | ||
| Concentrations to Divert: | ||
| –In Perforations (per perf.):4%7 | ||
| –Open Hole (lb/ft2 of Formation): 4%7 |
7. Unibead* OS-160 Buttons-OS-160 Wide Range
| -Melting Point – 192 ºF | ||
| –Soluble in:Oil | ||
| –Specific Gravity: 0.92 | ||
| –Type Well: Oil, Gasc | ||
| –Type Diversion: On perforations | ||
| On slotse | ||
| Concentrations to Divert: | ||
| – In Perforations (per perf.):1/4 to 1 lb | ||
| – Open Hole (lb/ft2 of Formation): 2.5 lb |
8. Graded Napthalene
| -Melting Point – 176 ºF | ||
| –Soluble in: Oil or gas | ||
| –Specific Gravity: 1.145 | ||
| –Type Well: Oil, Gasi | ||
| – Type Diversion: On perforations | ||
| On slots | ||
| In perforations | ||
| On formation | ||
| Concentrations to Divert: | ||
| – On Perforations (3/8′′ perforations) | ||
| 8 lb at 1/2 lb/gal or 2 lb at 2 lbgal f | ||
| – In Perforations (per perf.):14 to 1 lb | ||
| – Open Hole(lb/ft2 of Formation): 2.5 lb |
9. Unibead* OS-130 Buttons-OS-130 Wide Range
| -Melting Point – 155 ºF | ||
| – Soluble in: water or dilute acid | ||
| –Specific Gravity: 0.92 | ||
| –Type Well: Oil, Gasc | ||
| –Type Diversion: On perforations | ||
| On slotse | ||
| In perforations | ||
| On formation | ||
| Concentrations to Divert: | ||
| – In Perforations (per perf.): 1/4 to 1lb | ||
| – Open Hole(lb/ft2of Formation): 2.5 lb |
10. Unibead* OS-90 Buttons-OS-90 Wide Range
| -Melting Point -138 ºF | ||
| –Soluble in: oil | ||
| –Specific Gravity: 0.92 | ||
| –Type Well: Oil, Gasc | ||
| –Type Diversion: On perforationse | ||
| On slots | ||
| In perforations | ||
| On formation | ||
| Concentrations to Divert: | ||
| – In Perforations (per perf.):1/4 to 1 lb | ||
| – Open Hole(lb/ft2 of Formation): 2.5 lb |
* wax polymer
- If oil or gas is not making any water, a cleanup operation with dilute acid or brine may be required.
- If gas well is not making distillate, oil soluble resins should not be used.
- Unibead materials may be used in gas wells if temperature of zone exceeds the melting point of Unibead material, but zone must be cooled by preflush or the first stage of treating fluid to a temperature lower than the melting point. When the zone regains its original temperature, Unibead material melts and is removed.
- Oil soluble resin in salt solution and benzoic acid in alcohol solution will pass through a sand pack and bridges on the formation.They will also bridge in perforation.
- Unibead material will bridge on a 38 in. perforation, but the bridge will be weak.
- The lb represents the amount of diverting agent required to bridge on a perforation (open behind perforation) when used at the concentration listed (lb agent/gal of carrier fluid).
- Each perforation or sq. ft. of formation will take approximately 25 gallons of treating fluid containing 4% graded benzoid acid in alcohol solution before flow will be decreased to a minimum. The treating fluid must contain enough additional material to saturate it at bottom hole treating temperature.
- Material should not be considered for HF acidizing operations. Other bridging agents are compatible.
- Subliming materials. Should receive special consideration for gas well applications.
