申请人:King Fahd University of Petroleum and Minerals
公开号:US20210115322A1
公开(公告)日:2021-04-22
A well cleanup process involves removing an impermeable filter cake from a formation face with thermochemical and chelating agents to allow formation fluids to flow from a reservoir to a wellbore. The method may be used with oil and water-based drilling fluids with varied weighting agents, e.g., bentonite, calcium carbonate, or barite. Such thermochemical agents may involve two salts, e.g., NO
2
−
and NH
4
+
, which, when mixed together, can generate pressure and heat, in addition to hot H
2
O and/or N
2
. For example, the thermochemical agents may comprise Na
+
, K
+
, Li
+
, Cs
+
, Mg
2+
, Ca
2+
, and/or Ba
2+
with NO
2
−
and NH
4
+
with F
−
, Cl
−
, Br
−
, I
−
, CO
3
2−
, NO
3
−
, ClO
4
−
, and/or
−
OH. The thermochemical agents in combination with a chelator such as EDTA can removed the filter cake after 6 hours with a removal efficiency of 89 wt % for the barite filter cake in water based drilling fluid, exploiting the generation of a pressure pulse and heat which may disturb the filter cake and/or enhance barite dissolution and polymer degradation.