US2787326A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Removal of calcium sulfate scale
Assignee: Cities Service Research and Development Co
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Filing: 1954-12-31
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Granted: 1957-04-02
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Expires: 1974-12-31
Abstract
No abstract record available.
Inventors
- 👤 William B Hughes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:50
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/52; C09K8/528; Y; Y10; Y10S; Y10S507/00; Y10S507/927
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
152 words
THE METHOD OF INCREASING OIL PRODUCTION BY THE REMOVAL OF CALCIUM SULFATE SCALE FROM WELL TUBING AND THE SURROUNDING BORE HOLE WHICH COMPRISES INTRODUCING INTO SAID BORE HOLE A HOT AQUEOUS SOLUTION OF SODIUM BICARBONATE OF BETWEEN ABOUT 10 TO 20% BY WEIGHT, MAINTAINING SAID SOLUTION IN THE BORE HOLE FOR A SUFFICIENT TIME TO CONVERT THE CALCIUM SULFATE PRESENT TO CALCIUM CARBONATE, INTRODUCING A QUANTITY OF 10% HCI INTO SAID BORE HOLE IN AN AMOUNT SUFFICIENT TO DISSOLVE ALL OF THE CALICUM CARBONATE PRESENT IN SAID HOLE, FLUSHING SAID ACID FROM THE WELL, CIRCULATING A SECOND SOLUTION OF SODIUM BICARBONATE IN SAID WELL IN AN AMOUNT SUFFICIENT TO BUILD-UP A LAYER OF CALCIUM CARBONATE ON THE WELL TUBING SO AS MINIMIZE THE FORMATION OF CALICUM SULFATE SCALE ON-SAID TUBING, AND INTERMITTENTLY THEREAFTER CIRCULATING A DILUTE ACID SOLUTION THROUGH THE WELL TUBING AND SURROUNDING BOREHOLE TO PREVENT FORMATION OF CALCIUM SULFATE SCALE.
Claim 2
Independent Claim
152 words
THE METHOD OF INCREASING OIL PRODUCTION BY THE REMOVAL OF CALCIUM SULFATE SCALE FROM WELL TUBING AND THE SURROUNDING BORE HOLE WHICH COMPRISES INTRODUCING INTO SAID BORE HOLE A HOT AQUEOUS SOLUTION OF SODIUM BICARBONATE OF BETWEEN ABOUT 10 TO 20% BY WEIGHT, MAINTAINING SAID SOLUTION IN THE BORE HOLE FOR A SUFFICIENT TIME TO CONVERT THE CALCIUM SULFATE PRESENT TO CALCIUM CARBONATE, INTRODUCING A QUANTITY OF 10% HCI INTO SAID BORE HOLE IN AN AMOUNT SUFFICIENT TO DISSOLVE ALL OF THE CALICUM CARBONATE PRESENT IN SAID HOLE, FLUSHING SAID ACID FROM THE WELL, CIRCULATING A SECOND SOLUTION OF SODIUM BICARBONATE IN SAID WELL IN AN AMOUNT SUFFICIENT TO BUILD-UP A LAYER OF CALCIUM CARBONATE ON THE WELL TUBING SO AS MINIMIZE THE FORMATION OF CALICUM SULFATE SCALE ON-SAID TUBING, AND INTERMITTENTLY THEREAFTER CIRCULATING A DILUTE ACID SOLUTION THROUGH THE WELL TUBING AND SURROUNDING BOREHOLE TO PREVENT FORMATION OF CALCIUM SULFATE SCALE.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1960-04-01 | 1960-10-01 | 1961-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-04-01 | 1964-10-01 | 1965-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-04-01 | 1968-10-01 | 1969-04-02 | $7700.00 | Window Closed / Lapsed |