The removal of rock chips from the cutting face of the bit and the carrying of these cuttings to the surface is dependant on the flow properties (viscosity) of the drilling fluid. Viscosity is defined as the resistance by a fluid to flow. The driller recognises this as ’thickness’.

Polymers are employed to build viscosity for drilling fluids while improving borehole stability and maximizing core recovery through inhibition of water sensitive clays and shales. Bentonitic clays are also used to provide viscosity and to develop ‘gel strengths’. Gel strength develops when the mud stops moving and can be advantageous when drilling loose sand or gravel formations.

Bentonitic clays swell when mixed in fresh water, imparting viscosity and gel strength to the fluid. In addition, they assist in the movement of drill pipe and casing by the development of a thin filter cake on the walls of the borehole.

AMC products which perform primarily as viscosifiers are as follows:

AQUA-POL AUS-BEN AUS-GEL AUS-GEL XTRA AUS-TROL BIO-VIS CLAY BORE CR-650

EZEE PAC R LIQUI-PAC LlQUI-POL LP 2000 PAC R VIS-GEL XAN-BORE

Poor bit life, rod vibration and excessive rotary torque can be significant problems in deep and deviated diamond drill holes.

AMC has developed cutting oils which have extreme pressure lubrication properties designed for the operating parameters at the face of the bit. The concentrated blend of wetting agents, surfactants and corrosion inhibitors in AMC cutting oils, act to enhance the cooling of the impregnated diamond particles and accelerate the removal of fine cuttings improving penetration rates and extending bit life.

AMC cutting oils eliminate rod vibration and reduce rotary torque by depositing a soft, tenacious film of grease on the outside of the rods.

EP BIT LUBE and AMC-UNIVERSAL are vegetable oil-based, non-toxic biodegradable soluble oils. AMC UNIVERSAL can be used in harsh and salty waters, on the surface and in underground operations. EP BIT LUBE is suitable for fresh water surface systems while EP BIT LUBE (SW) has been especially formulated for salt water surface systems. Superlube is a new generation lubricant for deep diamond core drilling.

AMC BEL AMC BIODEGRADEABLE HAMMER OIL AUS-CUT ENVIRO-CUT ENVIRO-GREASE EP BIT LUBE EP BIT LUBE (SW)

HAMMER OIL LIQUID ROD GREASE PENETROL XTRA ROD GREASE XTRA TACKY SUPERLUBE TORQUE FREE XTRA TUBE LUBE UNIVERSAL

Filtration or fluid loss may be defined as loss of filtrate (water from water based muds) into permeable formations after these zones have been exposed to the drilling fluid through drilling operations. As a porous formation is exposed to the drilling fluid, mud solids are deposited on the wall of the hole in the form of a filter cake. The rate of fluid loss is proportional to the amount and quality of the filter cake. A thin robust filter cake will assist in reducing formation damage, improve drill rod lubricity and reduce the chances of differential sticking.

Fluid loss control additives include cellulose based polymers, lignites, bentonite clays, modified polysaccharides and some guar gums. AMC has a rangeof products which control fluid loss and may also be used to improve rheological properties of the drilling fluid.:

AUS-DEX AUS-LIG AUS-TEX HD LUBE

HD SPERSE LlQUI-SPERSE PAC L WELL CLEAN

FiltratSurfactants are drilling mud additives that function by altering the surface properties of the liquid and solid phases of the mud, or by imparting certain wetting characteristics to muds.

Surfactants may be used as wetting agents, emulsifiers, lubricants or foaming agents.

AMC has developed a range of products with these properties specifically for use in the mining and water well drilling industry.

AUS-DET XTRA SUPER-FOAM

Lost circulation problems can cause expensive rig down-time and increased costs through water transportation.
The crevices and fractures which cause lost circulation can be sealed with quick setting gypsum cements, particularly when drilling and setting surface casing.

AMC has developed a range of products which are applicable to cementing problems experienced by the drilling industry.

AMC XXX AUS-GRIP A & B FR-100L GROUND STABILIZER GYPSET HARD SET

WEIGHTING MATERIALS are used to control formation pressures, artesian aquifers and to reduce or eliminate formation caving.

The most commonly used material to weight up drilling fluids is BARITE (barium sulphate) which can be used to weight up muds in excess of 20 Ibs per US gallon (SG 2.40).

Where mud density is required in diamond drilling operations or in slim-hole oil and gas exploration, it is difficult to use barite because of the spin out effect due to the centrifugal force from high rotational rod speeds. In this situation it becomes necessary to use solids free brine.

CALCIUM CHLORIDE will increase the fluid density to 11.6 lbs/gal (SG 1.40) maximum.

POTASSIUM CHLORIDE is primarily used as a clay inhibitor, it can be used to increase fluid density to 9.7 lbs/gal (SG 1.62).

SODIUM CHLORIDE may be used to increase fluid density to 10.0 lbs/gal (SG 1.20) maximum.

Careful control of flow properties will be required to prevent settling when barite is added to a mud system.

Corrosion control can become a problem when CALCIUM CHLORIDE brine is used.

BARITE CALCIUM CHLORIDE POTASSIUM CHLORIDE SODIUM CHLORIDE

Diamond drilling and water well drilling fluids have different requirements from standard rotary drilling fluids as used in oilfield drilling. There are a number of techniques and specialty products used routinely in the oilfield which can be modified and adapted to mineral and water well drilling.
AMC continually researches existing techniques and equipment related to drilling fluids which may be adapted to the mineral and water well drilling industry.

AMC BIOCIDE AMC BIOCIDE G AMC DEFOAMER AMC K-ION PLUS AUS FLOC BLOCK AUSFLOC-L BACKFILL BENTONITE CHIPS

BENTONITE PELLETS Clay-Coat Xtra C-PACK INHIBI-SWELL P RESIDRILL ROD-FREE TRUCK WASH WATER CONDITIONER

Diamond drilling and water well drilling fluids have different requirements from standard rotary drilling fluids as used in oilfield drilling. There are a number of techniques and specialty products used routinely in the oilfield which can be modified and adapted to mineral and water well drilling.
AMC continually researches existing techniques and equipment related to drilling fluids which may be adapted to the mineral and water well drilling industry.

AUS-PLUG	Granulated polymer	For micro fractures and sands, its sealing properties are greatly enhanced when used with other LCM materials, for sealing thief zones where low circulating pressures exist .
MICA	Mica, fine, medium and coarse	Seepage loss, ideal for sedimentary formations, sands and micro fractures .
COTTON SEED HULLS	Cotton seed hulls	Suited in fine to medium sized fractures, vuggy formations with partial to total loss of fluid .
Bentonite Pellets	Pelletised Bentonite	Extremely effective in situations where total loss of circulation is experienced, in formations that contain large fissures, vugs or fractures. Pellets are initially coated in an inhibiting fluid before placement .
Bentonite Granules / Chips	Granulated Bentonite	Used under similar conditions to Bentonite Pellets, but are normally used in circumstances where the fractures and shearing is considered moderate .
KWIKSEAL	Mixture of fibres, flakes - fine, medium and coarse	Ideal for curing losses attributable to fractures and voids of varying sizes with total loss of fluid .
SHUR-SEAL	Shredded organic fibre	Suitable for a variety of thief zones, fine fractures, sands and broken formations .
POLY-GROUT	Fast setting chemical grout, forms a tough, water resistant rubber in a predetermined time .	An extremely fast setting grout designed to counteract loss circulation, provides support in fractures, shearing, poorly cemented formations, and helps prevent excessive water inflows .

AMC provides ecologically sensitive bio-chemical products known as the Eco Nutria range. These products enable the in-situ treatment and remediation of hydro-carbon from drilling rig sites, including polymers in sumps, and associated equipment. The Eco Nutria range eliminates the need for costly transportation of soil and / or liquids, off site incineration, storage or dumping. All Eco Nutria products are manufactured from natural materials and fibres, are biodegradable and environmentally friendly.

ABSORBENT MATS AND BOOOMS DUSTCLEAN DUSTDOWN ECO WASH EMD-S H2O GEL

HYDRO OILSORB OXYGEN BOOSTER REDS SOILCLEAN SUMPKLEEN SUMP-LOK

Drillable DISPLACEMENT PLUGS have been designed for use in diamond drilling rods and casing when cementing or running casing packs. Displacement plugs are made of natural rubber and the fluted design allows the plugs to be displaced with the rig pump.

APPLICATION
DISPLACEMENT PLUGS are particularly suited to cementing deep diamond drill holes. The plugs can be used to isolate the cement slurry from the drilling fluid reducing or eliminating dilution and contamination.
The plugs can also be used to set a casing pack in the casing annulus to aid in recovery of the casing.

PACKAGING
DISPLACEMENT PLUGS are available in NQ, HQ, PQ sizes.

MUD BALANCE
One of the most important properties monitored throughout the drilling operation is the mud weight. The mud balance consists of a beam with a mud cup at one end and a fixed counterweight at the other end, with a sliding weight rider moving along a graduated scale. A level bubble is mounted on the beam to ensure accurate balancing.

MARSH FUNNEL AND CUP
Viscosity and gel strengths are measurements that relate to the flow properties of fluids. The funnel viscosity test gives an indication of changes in flow properties, but to be effective, measurements must be taken and recorded regularly.

pH PAPERS
Field measurements of drilling fluid pH are fundamental to drilling fluid control. Clay interaction, solubility of components and contaminants, and overall effectiveness of additives are all dependent upon pH. Solutions with a pH value less than 7 are considered ‘acidic’ and those with pH values greater that 7 are considered ‘alkaline’ while pH 7 is ‘neutral’. In the field pH papers are typically used to measure the pH of a drilling fluid.

SAND CONTENT KIT
One of the primary functions of a drilling fluid is to carry drilled solids from the hole. These solids are a contaminant and if left in the system can lead to numerous problems. The Sand Content Kit determines the volume percent of sand sized particles in the drilling fluid. The kit consists of a glass tube graduated to read percent by volume, a funnel and a 200 mesh sieve contained on a cylindrical shaped holder.

Hole Volume in litres
Depth of Hole x Hole Dia mm²

Assume Hole Diameter 187mm and the depth of hole is 100 metres
100 x (187mm x 187mm) ÷ 1270 = 2753 litres

Up Hole Velocity
1270 x Pump Output Litre/Minute
(Hole Diameter mm² - (Pipe Diameter mm²) = Metres per Minute

Annula Volume
Hole Diameter mm² - Pipe Diameter mm²
                             1270                                = Litres per metre

The heart of any mud circulating system is the mud pump, which is the primary factor in the effectiveness of hole cleaning. Common pumps in the industry are TRIPLEX, DUPLEX and CENTRIFUGAL. Of these, the duplex is generally the easiest to regulate, as the pump rods are visible. By counting the number of strokes per minute the pump output can be accurately determined.
For both the triplex and duplex pumps, one stroke is designed as ‘1 up and 1 back for each pump rod’. By varying the speed of the pump, the number of strokes can be increased or decreased which regulates the pump output.
In the case of smaller triplex pumps, such as ‘Bean’ pumps so common in diamond drilling operations, the pump rods are enclosed and therefore not visible, so that pump strokes cannot be counted. The best method of determining output of these pumps is to physically measure the output of the pump at a specific RPM in a specific gear in the gearbox. This should be done on a regular basis to compensate for wear factors in the pump.
Pump output rates from these popular Bean and FMC triplex pumps are quoted in US Gallons per minute, so it will be necessary to convert these to litres per minute as required. This is simply done by multiplying the US gallons p/m by 3.785 to arrive at litres p/m.