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DRILLING
the Frasnian stage of the Devonian
System. This method is based
on storage of samples in fluids till
appearance of visual destruction
(due to swelling and disintegration)
of clay structure. The testing results
of several types of flushing water are
provided in comparison Table 3.
FIG. 1. Rock samples from mud testing: 1 – SSBPDMI, 2 – polymerclay mud, 3 – SSBPDM
Prior to testing:
TABLE 3. Laboratory testing results
Time to
Mud type
appearance of
destructions, h
Fresh water 0.05
Polymerclay 18
SSBPDM 100
SSBPDMI > 150
Formation water
р = 1.17 g/cm 3 120
In the process of well construction,
the time of impact of drilling mud on
unstable intervals of log until loss
of their stability and occurrence
of caving formation is of no small
importance.
Data of laboratory testing shows
the advantage of the inhibiting
ability of SSBPDMI over other
similar fluids under examination
After testing:
1 2 3
that is also confirmed by field data
received during drilling of row of
wells at the oilfields of Udmurtia.
Time to occurrence of caving
formation using SSBPDMI is 4 days.
During drilling using polymerclay
mud, it is 24 hours, using SSBPDM
– 2 days. This data is summarized in
Table 4.
TABLE 4. Time to occurrence of instability
of the Kynovian horizon formation since
interval penetration
Mud type
Time, hour
SSBPDMI 98
Polymerclay 24
SSBPDM 48
Conclusions
Drilling mud treated with
sulfonated asphalt in form of
Soltex additive reduces the risk of
caving formation and breaking of
unstable formations (argillites) by
colmatizing micro fractures with
finely-divided oil-soluble part of the
reagent.
In addition, this reagent has the
following advantages:
• it minimizes the damaging of
producing formations;
• it reacts with shale to stop its
sloughing and swelling;
• it significantly increases lubricity;
either alone or synergistically with
small amounts of oils or synthetic
oils;
• it inhibits the dispersion of drilled
cuttings;
• it reduces fluid loss of drilling
mud, reduces dispersability (size
degradation) of cuttings particles
in the process of drilling.
References
1. S.B. Svinitskiy. Forecasting of mining and
geological conditions of drilling wells of salt and
clay deposits with anomalously high pressure of
fluids: thesis of Dr. Sci. in Geology and Mineralogy.
Stavropol, 2007.
2. V.I. Ibrayev. Forecasting of stress conditions of
reservoirs and reservoir-seal rocks of oil and gas
deposits in the Western Siberia. Tyumen: Tyumen
Printing House OJSC, 2006.
3. R.D. Kanevskaya. Mathematic simulation of
development of oil and gas deposits with
application of hydraulic fracturing. Moscow: Nedra-
Business Center LLC, 1999.
4. I.V. Dorovskikh, A.A. Podiyachev, V.A. Pavlov.
Influence of mechanical characteristics change of
rocks during mud saturation on the stressed state
of near-wellbore area // Burenie i Neft. – 2014. –
No.11. – P. 31 – 38.
5. V.N. Koshelev. Development and improvement of
methods for selection and compositions of drilling
fluids: thesis of Ph.D. in Engineering Science, 1988.
6. Chenevert V.E. Glycerol mud additive provides
shale Stability// Oil and Gas J.-II.87. – No.29. –
P. 60 – 64.
7. Recommended Practice for Laboratory Testing of
Drilling Fluids / Note: EIGHTH; ISO 10416:2008
Adoption; Supersedes API RP 131. – P.73 – 75.
8. Method of evaluation of inhibiting abilities of
drilling fluids: AS 1222670 MKI S09К7/00 / A.I.
Penkov, A.A. Penzhoyan, V.N. Koshelev. – Stated
15.08.83 Published 07.04.86. – BI No.13 – P. 3.
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