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Title: Preventing gravel pack and formation dissolution during steam injection

Conference · · Soc. Pet. Eng. AIME, Pap.; (United States)
OSTI ID:5199129

Gravel pack and formation dissolution during steam injection can cause well failures and formation damage. Silicate minerals dissolve in the hot alkaline water injected with steam. This paper describes the use of ammonium salts in preventing dissolution by reducing the pH of generator effluents from 11 and greater to values between 9 and 10. These salts, such as ammonium chloride and ammonium nitrate, do not significantly effect feedwater pH; rather, they reduce effluent pH by decomposing during steam generation to neutralize the alkalinity yielded by bicarbonate decomposition. This process is also described in U.S. Patent No. 4,475,595. Silica dissolution was investigated by flowing both liquid and vapor through tubes packed with gravel. In one case, dissolution from a consolidated core in hot alkaline water was also studied. These tests demonstrate the the effectiveness of ammonium salts in controlling pH and reducing gravel dissolution. Both ammonium chloride and ammonium nitrate have been field tested in steam generators. Ammonium nitrate was added to feedwater at a central facility to determine the simultaneous effect of treatment at five generators operating under different conditions. These tests show that treatment with NH/sub 4/NO/sub 3/ controlled pH within acceptable limits at all generators.

Research Organization:
Union Oil Co. of California
OSTI ID:
5199129
Report Number(s):
CONF-830512-
Journal Information:
Soc. Pet. Eng. AIME, Pap.; (United States), Vol. SPE13660; Conference: IEE/APS symposium, Houston, TX, USA, 23 May 1983
Country of Publication:
United States
Language:
English