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Home > Rental > Drilling Equipment > Downhole Drilling

Downhole Drilling

Downhole Drilling

Our goal is to supply quality downhole drilling tools designed to withstand today's harsh drilling conditions at economical cost to our customers. We have an extensive fleet of high quality downhole tools for drill string and bottom hole assemblies.


A reamer is a tool that is part of the bottom hole assembly and is used to enlarge and maintain the wellbore to full gauge hole size and smooth the wall finish for easier logging and casing runs, improve bit performance and life, reduce torque and vibration.


Available size range: 4 ¾” - 36”


A stabilizer is a piece of downhole equipment that will center the collars in the hole and thus mechanically stabilizes the bottom hole assembly in the borehole in order to avoid unintentional sidetracking, and vibrations to ensure the quality of the hole being drilled.


Integral blades: 4 1/8” - 26”
Welded blades: 23” - 36”

Hole Openers

A hole opener is used to enlarge the borehole during a well drilling operation. It can be positioned either above the drill bit or above a pilot run inside the existing borehole. Cutter types are available for soft to extra hard formations.


Available size range: 3 ¾” - 36”

Cup Testers

Cup testers are attached to the drill string and lowered into the casing below the wellhead to pressure test the annular blowout preventer stack and the wellhead.

The cup tester assemblies are rated to the API standard mill test pressure for the casing sizes up to 10.000 psi and special reinforcing up to 15.000 psi is available upon request.

Available size range: 4 ½” - 20”
Mandrel & Subs NC26 - NC50

Safety & Kelly Valves

The Safety Valve can be stabbed into the top joint of drill pipe or tubing at the rig floor and closed quickly in case a well kicks. The Kelly Valve or Full Opening Safety Valves (FOSV) can be used as drill pipe safety valve, upper kelly cock to control blowout pressures by shutting off flow in the drill string or as a lower kelly cock to stop mud loss when the kelly is disconnected from the drill string.


Various type and connections

Working pressures of 10.000 and 15.000 psi

Standard or H2S trim

Drop-in Check Valves

Drop-in Check valves provide protection from backflow through the drill pipe during  a kick or  when the drill string is left open.


Various type and connections

Working pressures of 10.000 and 15.000 psi

Standard and H2S trim

Inside Bop Valve

During normal circulation of drilling fluids down the drill pipe the IBOP or Gray valve remains open to allow the flow through it.   It prevents backflow by closing automatically. Besides controlling the kick it protects the drilling equipment as well.


Various type and connections

Working pressures of 10.000 and 15.000 psi

Standard and H2S trim


Drill subs are an important part of every day drilling and to connect drilling tools in to the bottom hole assembly and drill string. To meet the most demanding drilling requirements a wide range of subs with standard API, High Torque,  Double Shouldered, Grant Prideco, VAM, Tenaris/Hydrill, WECO and other proprietary high performance connections are part of our inventory.

  • Bit Subs – Connect the bit to the drill string with usually 2 box connections

  • Swivel Subs – Double-pin subs that connect the swivel to the kelly valve

  • Kelly Saver Subs – Save threads on the Kelly valve

  • Crossover Subs – Allow change from one thread type to another

  • Pump-In Subs – Allow heavier/lighter mud to be circulated into the drill string

  • Lift Subs – Allow lifting out the drill string

  • Drill Collar Subs – Allow connection between drill pipe and drill collar

  • Float sub –Contains a one-way check valve to prevent drilling mud and cuttings flowing back up the drill string

Available size range: 1 ¼” – 11”

Various type and connections

Circulation Sub

A Circulation sub can be installed either above the bit or downhole motor to increase mud circulation to affect good transport of cuttings and hole cleaning before the string is retrieved. The sub is being activated by dropping a  chrome steel ball down the drill string which opens a path to the annulus and diverting the downhole flow.


Available size range: 3 1/8” - 9 ½” (Drop-ball activated)

Universal Bottom Hole Orientation (UBHO) Sub

The UBHO sub is typically run directly below a drill collar and contains a landing sleeve for directional survey equipment.  For directional drilling it is essential to know the tools orientation in the wellbore.


IOT Holland is the exclusive distributor of the Dynomax product line

Mud Motors

“Predictable Performance and Extreme Reliability.” 


A mud motor or drilling motor is a progressive cavity positive displacement pump placed in the drill string to provide additional power to the bit while drilling. Drilling fluid or mud is used to create eccentric motion in the power section of the motor which is transferred as concentric power to the drill bit (well). The mud motor uses different rotor and stator configurations to provide optimum performance for the desired drilling operation, typically increasing the number of lobes and length of power assembly for greater horsepower.

Dynomax Mud Motors are engineered and designed for durability and consistency as they provide additional power to the drill bit. They offer different rotor and stator configurations to provide optimum performance while drilling, and they have the capacity to drill large-sized holes used by larger rigs.


Dynomax Mud Motors reduce bearing loads and differential pressure while maintaining seal through drill string operation. Dynomax Mud Motor’s leading design provides adjustable bent housings while still accommodating high torque field scenarios.


  • High speed rotation rate enables deep penetration

  • Performs well in very hard rock formations

  • Motors incorporate a wide range of power sections in sizes ranging from 2-7/8” (73mm) to 11-1/4” (268mm).


  • Custom designed thrust bearing maximizes load while optimizing space.

  • Splined drive shaft to distribute an even load over the splines; with reduced vibration.

  • Adjustable bent housing (0° to 3° in 13 increments) or a fixed bent housing.

  • Flow restrictor that reduces pressure in the bearing assembly to a near balanced condition and extending seal life.

  • Employs the patented Kalsi Rotary Seal – a seal that has been successfully run in down hole drilling applications for over 20 years.

  • Includes increased internal drive line dimensions to accommodate more torque required in today’s drilling operations (e.g. Extended and Even Wall power sections). 


Dynomax Mud Motors are proven to operate in extreme drilling conditions. They increase the rate of penetration and can therefore reduce drilling times.


"Proven oilfield performance.”

There are two primary types of drilling jars: hydraulic and mechanical. They are used downhole to deliver impact load to another downhole component that is stuck. Energy is stored in the drill string and suddenly released by the jar when it fires. Fishing jars operate similar and both deliver approximately the same impact blow, but the drilling jar is built such that it can better withstand the rotary and vibrational loading associated with drilling.

Our Drilling Jars remain one of the most versatile, reliable and safe assembly systems in the oilfield industry. Dyno-Jars are designed for a wide range of drilling applications to meet the demands of high-temperature, extreme and extended use during drilling procedures.


Dyno-Jars have a longer stroke length, which increases the oil flow in the top of the tool, creating greater jarring impact without additional pulling on the drill string. Pressure compensation ensures pull accuracy, zero pressure differential and increased seal life.


Dyno-Jar’s unique latch design provides better wear characteristics that withstand extended jarring operations, and they can fit most standard mouse holes, making connection to drill string assemblies easier.


  • Long operational life, and can withstand high temperatures.

  • Hydraulic time delay feature which gives control of the impact load and also makes the hoisting equipment safe against any possible damages. 

  • Mechanical lock on the jar prevents accidental firing. 

  • Large internal diameter which allows high volumes of fluid passage while maintaining optimum strength in the jar.

  • Can be operated in either tension or compression mode.


"An Innovative Solution to Today's Drilling Requirement's"

Today’s drilling applications are becoming more challenging with deeper, longer and more complex wells being drilled faster than ever before. One challenge is keeping the hole clean while drilling, which is achieved with higher flow rates. These flow rates are limited by the power sections on the motors and quite often lead to premature failure due to over-pumping.


The Regulator employs a variable size exit orifice to actively moderate the flow that goes through the motor continuously – extra fluid is vented out the side. The exit orifice is controlled by a valve that measures the flow entering the motor. The valve mechanism responds in milliseconds so that flow to the motor is always regulated.


  • Reduce stator failures due to over pumping

  • Utilize optimal performance of the power section in motors

  • Reduce washing out of components in the motor

  • No need to drop balls or darts for activation

  • Motor stalls are still visible at surface

  • Applicable not only conventional drilling, but also coil tubing, and completion operations

Shock Tools

“Reducing Impacts for Smooth Operations.”

The Shock Tool or Shock sub is a drill string component that absorbs and dampens the variable axial dynamic loads produced by the drill bit during routine drilling and milling operations. Reducing the impact loads helps to increase ROP; improve borehole quality; and extend the life of the drill strring assembly. 

Whether performing through normal, deviated or deep wells, your drill string assembly must withstand the extreme conditions including torsional vibration, axial oscillations/loads and drill string harmonics.


Dynomax Shock Subs are designed for a wide range of drilling environments and extreme conditions. Shock Subs improve the life and durability of your drill string assembly, improving online efficiency and operating costs.


Our Shock Tools are designed for easy assembly and easy service. They can be combined into drill strings with other downhole tools quickly, and can be detached, reducing service time and costs. 


Every Dynomax Shock Tool undergoes stringent performance tests, and we ensure that our testing models and QA/QC programs meet or exceed any in the oilfield industry.


  • Significant vibration absorption.

  • Reduction of drill string harmonics.

  • Smoother and faster drilling downhole.

  • Longer bit life.

  • Protect instruments and body connections.

  • Increased Tool bearing life.


Slide Reamer

"Traditionally, drilling, conditioning and reaming were separate phases of a drilling project. The revolutionary patented Dynomax slide reamer integrates these phases seamlessly."

The cutting structure on the slide reamer is designed to maintain 360 degree contact. Cutters rotate independently throughout the movement, reducing rotary torque and drag by up to 20% (when compared to running a drill string without a slide reamer)


Dynomax Slide Reamers used for vertical, directional and horizontal holes eliminating drift or deviation in wellbore applications.


Cutters clean the wellbore while sliding or rotating, maintaining integrity of the wellbore wall in any drilling operation. The patented cutter design cuts perpendicularly with the wellbore surface, unlike traditional reamers which run parallel to the wellbore.


The Dynomax Slide Reamer reams while sliding, and can also ream during drill string rotation. This continuous conditioning eliminates the need for designated ream runs. Slide reamers can be attached to the drill string for multiple drilling applications.


Our Slide Reamers are uniquely versatile drill string component. The Cutters can be redressed with hard-faced replacement cartridges and the component can be reattached as a Slide Stabilizer, which centers the drill string and BHA and reconditions the wellbore.


  • Integral blade cutters providing 360 degree wall contact.

  • Cutters turn with each movement of drill string (Rotating, Sliding and Tripping).

  • Allows optimal fluid passage.

  • More cutting surface area than traditional roller reamers.

  • Reduces torque and drag.

  • Designed to minimize failures at high stress points.

  • Two tools in one. Many different variations can be run on the same tool.

  • Sealed Bearing design.

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