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Wellbore Enlargement Test in a Gas-storage Well.

Authors
Heath-LJ; Huff-RV; Jones-RA
Source
NTIS: PB 192 034 :17 pages
Link
NIOSHTIC No.
10009025
Abstract
Wellbore enlargement was tested using hydrazine hydrate in a gas- storage well in Ohio to increase the well productivity. The wellbore was to be enlarged by chemical disaggregation of the sandstone adjacent to the wellbore. Productivity immediately declined 49.1 percent and gradually declined to zero in 7 months. A down-hole camera survey showed a white-to-gray precipitate covering the entire wellbore surface. The precipitate was chemically analyzed and identified as mostly carbazic acid, a hydrazine derivative of carbonic acid. Formation of this precipitate was not anticipated; this viscous substance caused the gradual loss in productivity of the well. The wellbore was not enlarged. Laboratory tests were run to determine what clay stabilization measures could be taken in sandstone cores to prevent clay swelling and particle migration caused by hydrazine hydrate. Normal clay stabilization methods did not prevent the virtually complete loss in permeability to hydrazine hydrate. Other laboratory tests using natural gas diluted with small amounts of carbon dioxide confirmed the ease with which carbazic acid could be formed in a hydrazine hydrate-saturated environment within and adjacent to the wellbore.
Publication Date
19700101
Document Type
IH; Report of Investigation;
Fiscal Year
1970
NTIS Accession No.
PB-192034
NTIS Price
A03
Identifying No.
RI 7382
NIOSH Division
BERC;
Source Name
NTIS: PB 192 034
State
OH;
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