Page 17 - A Primer of Oilwell Service and Workover Completion

WELL STIMULATION 

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Petroleum Extension-The University of Texas at Austin

WELL STIMULATION

ell stimulation includes Well stimulation overcomes For a time in the s, lease
Wtechniques for overcom- low permeability by creating operators experimented with
ing the problem of a tight for- new flow channels or enlarging nuclear explosives in a limited
mation, or one that has a low old ones. There are three ways to number of gas wells. While this
permeability. Remember that do this. The oldest method is to method increased production
permeability is a measure of use explosives. During the s, somewhat, the cost was prohibi-
how well the pores that contain acid stimulation, or acidizing, tive.
hydro carbons are connected to became commercially available. Oil companies are still inter-
each other. Extracting the hydro- Hydraulic fracturing, the third ested in explosive techniques
carbons from tight reservoirs is stimulation method, was intro- because certain kinds of tight
difficult and slow. On the other duced in . formations do not respond
hand, the natural permeability readily to either acidizing or
of the rock may be adequate, but EXPLOSIVES hydraulic fracturing. Research
the formation near the wellbore continues in an effort to find
may be damaged in a way that As early as the s, crews other techniques that might
restricts the flow channels in exploded nitroglycerin inside increase production, but fractur-
porous rock. Formation damage wells to improve their productiv- ing and acidizing are currently
can occur during drilling, com- ity. They simply lowered a nitro the most effective well stimula-
pletion, work over, production, charge into the open hole on a tion methods.
or injection. conductor line and detonated it
Low permeability, whether to fracture the formation. Nitro
natural or artificial, reduces shooting was fairly routine until
productivity to a rate that is not the advent of acidizing and
economical. Well stimulation hydraulic fracturing.
is successful enough that many
wells are stimulated immedi-
ately after completion and then
whenever production drops
because of low permeability.

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