Surgil ESIA Report - Volume III - EKN

“Management of Ustyurt GCC infrastructure objects
and Surgil GCF construction” UE »
7. ANALYSIS OF DRILLING MUD DESIGN COMPOSITION AND PA-
RAMETERS. DEFINITION OF DRILLING MUD AND FORMED DRILL-
ING CUTTINGS DANGER CLASS
7.1. There is apply as materials to drilling mud preparation and regulation of its properties: bentonite,
caustic and ash soda, KMS К-4., and etc. All technological processes package is meant technology
of flushing-out of well with operations on drilling mud preparation, clearing, treatment and
circulation with use of the equipment and devices for their performance and control. Wells flushingout
technological process is realized so that to achieve best technical and economic indexes of drilling
with observance of measures for environmental protection.
7.2. Drilling process consists in rock failure by chisel with drilling rock transportation (flushing) by
drilling mud onto surface. Type of drilling mud and its formula are selected proceeding from miming
and geological conditions of hole making, with a glance of their least harmful impact on soils
and underground waters in accordance with current CD.
7.3. There are applied the following technological materials for drilling mud preparation and treatment
during well drilling and fixing: gel material, soda ash, caustic soda, К-4, oil, CMC, FCLS,
graphite, cement and others. All above-stated materials basically are nontoxic and transported in
compact bags and barrels. They are stored in specially allotted places under shelters and in sheds on
the oilrig.
7.4. Gel materials represent dry and ground clay with chemical reagents or without them. For drilling
mud preparation there is used basically gel materials from bentonitic, hydro micaceous (local)
and palygors-kite clays, each of which contains various impurities of other minerals. There is 70%
and more of the montmorillonite mineral in bentonitic gel materials.
7.5. It is accepted to subdivide of bentonites into alkaline (sodium), alkaline-earth (calcium). There
are prevailed univalent metals Na + and K + in composition of the sodium bentonite exchange capacity.
Sodium bentonites possess high osmotic pressure, good swelling and dispersed in water, can
turn into calcium (by liming), have high slurry yield. Calcium bentonites have low osmotic pressure,
poorly swelled and dispersed in water, can turn into sodium (soda ahs additive), have low slurry
yield.
7.6. Oil is the organic substance containing various solid hydrocarbons and tarry matters. Depending
on their composition the oil divided into high-gravity and heavy. It is applied in drilling mud
composition as greasing additive to improvement of drilling process: reduction of freeze-in danger,
increases of chisel operating efficiency, decrease in hydraulic resistance.
7.7. Caustic soda is colorless opaque crystal mass. It is used basically for regulation of drilling mud
рН. Drilling mud treatment is carried out by 5-10% caustic soda solution, as the large additives lead
to bodying and filter loss increase and deterioration of drilling mud properties. It is delivered in a
hard form in iron barrels (drums) by mass of 100-200kg or in the form of 40-47% concentration solution.
NaOH strongly absorbs moisture and carbonic gas in air, turning into carbonate. During dissolution
allocates of heat considerable amount. It does not form dust. MPC is 0.5/m 3 .
- 15 -