Drilling Technology Drilling optimization more than specific technologies

Mike Slaton Contributing Editor Faster drilling offshore is increaseingly dependent upon a host of highly specialized technologies. Phot coutesy of Bowen Tools and Sundowner Offshore Services, a Nabors Industries company.


Drill bits

Hughes Christensen: Recent product introductions at Hughes Christensen include the "GT" series Tungsten Carbide Insert (TCI) and Steel Tooth rock bits, designed to improve penetration rates and drilling efficiency without sacrificing overall durability.


Hughes Christensen: AG575 PDC bit with shearing action.

TCI bits feature improved cutting surface structure geometries primarily on the outer portion of the bit. Small, self-sharpening inserts or hard metal pads have been strategically placed between the heel row teeth to aid in cutting by removing rock ribs normally left by conventional rolling cone bits. The GT series steel tooth bits also feature TCI gage trimmers and a proprietary Endura (TM) hardfacing.

A new PDC Gold Series is designed to reduce fracture accelerated wear that lowers penetration rates and shortens bit life. In what Hughes Christensen describes as a new approach to diamond cutter engineering, the series incorporates four cutter elements: the CSE cutter (known as the buttress cutter), the polished cutter, stress engineered cutters and engineered cutter replacement.

Reed Tool Company: Reed is introducing a new technology that combines performance capabilities from milled tooth bits and insert bits. Marketed in it's Powdered Metal Cutter (PMC) bit line, the technology employs a "Powdered Metal Cutter" with integral hardmetal inlays. The PMC process produces a precision-forged cutter. The hardmetal inlay process provides a higher tungsten carbide concentration and allows for twice the thickness in protection in the crest of the tooth versus a welded deposit.

The PMC bit has a longer life because it is more abrasion resistant, has faster penetration rates because the teeth stay sharper longer, and has more consistent performance because the integral hardmetal is custom designed and precisely controlled.

Hycalog: Hycolog's DS68 PDC bit employs several enhancements to increase penetration rates and bit life, including venturi nozzles that direct mud flow towards the nose rather than the pin connection, and a primary-secondary blade configuration designed to cut more formation while stabilizing the bit.

Security DBS: Security DBS's recent innovations include:

  1. A new line of whirl resistant bits, the FM2000 Series, geared towards the high flow volumes used in offshore operations.
  2. Initial field tests are being conducted with a pair of near-bit, downhole vibration technologies. These new tools are designed to maintain the bit's engagement with the rock face and to control the vibrations experienced by the bit and BHA.
  3. Newly upgraded roller cone motor bits have been engineered to withstand the stresses of directional and high RPM drilling.
  4. ERA (Enhanced Return Area) bits with forged arms mounted on a connection base which also carries the jet nozzles. They provide greater strength and as much as 20% greater annular clearance for improved cleaning and cuttings transport.
  5. Slim hole coring systems and new proprietary thread design.

Smith International: Diamond Enhanced Inserts have been introduced with polycrystalline diamond applied to a carbide base giving wear resistance with impact resistance. By virtually stopping wear through abrasive formations, reaming is reduced. Shaped inserts, combining high abrasion resistance with faster ROP are now being built.

  1. PDC bits with cutter plurality, load balancing, unsymmetric blade placement and spiral blades improve bit stability and reduce vibration and whirl.
    Sculptured tungsten carbide bit inserts with revolutionary shapes optimize durability and penetration rate.
  2. The FDS+radius drilling-crest, milled-tooth bits have increased footages by an average of 30% over conventional milled tooth bits.
  3. Heel row, chisel-shaped carbide inserts on milled tooth bits help maintain full gage hole longer and protect the seal.
  4. High speed seals, Spinodal bearings, and crowned roller bearings have expanded the range of operating parameters that roller cone bits can be run under.

Rockbit International: Two of RockBit's most recent products are:

  1. A Lugged Reaming Gage (LRG) Series bit series for steerable motor systems that is designed to increase wear resistance and to stabilize and maintain gage longer
  2. Vectored LRG Bits featuring reorienting cutters that more fully contact the formation to provide more aggressive strata gouging.


Dowell: Key hardware advances made by Dowell Drilling Fluids Services are the MSM (muds solid monitor) and FMP (fluids monitoring package). MSM Monitors provide a fast, accurate and convenient method for determining low gravity solids and barite content in the drilling fluid using X-ray fluorescent spectroscopy (XRF). FMP monitoring packages continuously measures density, viscosity, temperature, conductivity and pH of the drilling fluid.

Recent product advancements from Dowell include Quadrill, Ultridrill and Visplex drilling fluids. The Quadrill system is a newly released water-based fluid with shale inhibitors designed to replace oil-based mud in environmentally sensitive areas. Ultridrill fluid is a synthetic drilling fluid system comprised of a low viscosity, synthetic hydrocarbon of non-petroleum origins which produces a low toxicity and easily biodegradable fluid.

Visplex fluid is a water-based, non toxic fluid, primarily designed for high angle and horizontal drilling because of its excellent transport and non-damaging properties. It uses mixed metal hydroxide technology.

M-I Drilling Fluids: Some recent innovations M-I Drilling Fluids has brought to the market include:

(1) Novadril - M-I's synthetic drilling fluid developed to provide the drilling performance benefits of an oil-based mud without the environmental disadvantages. The use of synthetics eliminates the costs associated with disposing of oil muds. Results and case histories indicate that, in comparison to water-based fluids, synthetics experience excellent penetration rates, good hole cleaning, stable wellbores and greater lubricity.
(2) Flo-Pro - a drill-in fluid, was designed to maximize the production potential of horizontal and high-angle wells. In addition to a significant improvement in production and ROP, the low coefficients of friction minimize torque and drag, often a significant factor in drilling long horizontal and extended reach wells.

Drilling systems

Sperry-Sun: Sperry-Sun's recent advancements include:

  1. The TPH (Tandem Power Head) and Sperry Drill downhole motors double available power to the bit and can commonly increase ROP 2-3 times.
  2. Adjustable Gage Stabilizers allow incremental changes in build or drop tendencies of a given BHA without tripping out.
  3. Underbalanced horizontal drilling with gas injection. The technique, which has been used in over 225 wells to date, increases ROP and decreases drilling problems - notably lost circulation and stuck pipe as well as reducing skin damage.
  4. Multi-lateral horizontal wells increase the drainage area of a well.
  5. Twining horizontal wells uses special directional control devices to allow two horizontal wells to be drilled with a precise separation over the length of their laterals (used in the EOR technique of steam assisted gravity drainage).
  6. The Slimphase 4 4-3/4-in. OD multiple depth of investigation MWD resistivity tool allows geosteering in slim holes.
  7. The DDS Drillstring Dynamics Sensor detects damaging BHA vibrations in three axes as they occur.

Anadrill: A major introduction by Anadril is the company's GeoSteering tool, developed to provide highly accurate, real-time steering. The system is comprised of a PowerPak motor modified at the bottom end to have geological sensors of resistivity and gamma ray.

The IDEAL drilling system integrates downhole directional power with at-the-bit measurement technology that allows more efficient, accurate drilling.

The company's PowerPak XP (Extra Power) uses extended motor power sections to provide a 50 -70% increase in output power without only a small increase in length of the power section.

In response to slimhole markets, Anadril has introduced an extremely small 2-7/8-in. PowerPak motor, and a slim hole MWD tool called Slim 1.

Drilex: Drilex was among the first companies to re-introduce the tandem motor. The effort was prompted by a realization that horsepower was being lost at the upper end of the motor's power curve due to lower motor RPM. Adding a second power section not only doubled available torque, horsepower lost to reduced RPM was recovered by running the motor lower on its power curve.

The next step was the design of a single piece power section with the higher torque and horsepower characteristics of tandem motors. That motor design was recently introduced in a 4 3/4-in. version that is under 20 ft. in length.

Copyright 1995 Offshore. All Rights Reserved.

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