Directional Drilling Rentals

Rental strings for directional and horizontal drilling

Directional and horizontal drilling deliberately steers the wellbore away from vertical to build angle and hold a lateral through the reservoir — now the dominant approach in unconventional plays. These wells load the string differently from a vertical hole: high torque and drag as pipe is dragged against the borehole wall, cyclic fatigue in the build section, and the need to keep magnetic survey tools reading cleanly. That makes component selection — non-magnetic collars, spiral HWDP, stabilizers and crossovers — central to a successful well. Drillstrings rents these directional components, inspected and serialized, so the string is built for the well plan without tying up capital.

Building the directional BHA

• Drill collars, including non-magnetic collars, provide weight-on-bit and isolate the MWD tool from magnetic interference for accurate surveys.
• Heavy-weight drill pipe in spiral form reduces wall-contact area and differential-sticking risk while smoothing the stiffness transition and adding controllable weight.
• BHA components — stabilizers, crossover subs and the fittings that control the assembly and connect mismatched thread forms.
• Downhole tools cover jars, shock subs and the additional tools a steerable assembly needs.
• Drill pipe in the right grade — commonly 5” or 5½” S-135 for long laterals — carries the torque to surface.

Torque, drag, fatigue and MWD isolation

The four constraints that shape a directional string are torque, drag, fatigue and survey accuracy. Torque and drag are managed with spiral HWDP, stabilization and correct connection selection; fatigue in the build section is managed with grade choice and inspection class; and survey accuracy depends on placing non-magnetic collars around the MWD tool. Our guides to directional and horizontal BHA essentials and drill string design fundamentals work through these trade-offs in detail.

Grade, connection and fatigue in the build

The build section is where fatigue is most punishing: every rotation cycles the pipe through the dogleg, so dogleg severity and rotating hours drive fatigue at the tool joints. High-strength S-135 carries the torque of a long lateral, and premium double-shoulder connections add torque capacity and fatigue resistance over standard API joints (NC46, NC50, FH). But higher grade is not a cure for fatigue — inspection class and connection condition matter as much. Specify Premium-class pipe (≥80% remaining wall) for high-dogleg, high-torque directional work, and keep tool joints gauged and in good shoulder condition. Our drill pipe grades explained guide covers the grade side of this decision.

MWD isolation and survey accuracy

MWD survey tools read the earth’s magnetic field to determine azimuth, so they must sit inside non-magnetic (monel) drill collars that isolate them from the steel string. The required length of non-magnetic material depends on hole inclination, azimuth and magnetic latitude — too little spacing and the survey is corrupted by the string’s own magnetism. Placing the correct non-magnetic collar length above and below the MWD tool is part of building a clean-surveying BHA.

Common pitfalls

• Under-graded pipe in a high-torque lateral — torque exceeds the connection rating and the string twists off.
• Standard connections where premium is needed — fatigue at the tool joint in the build section.
• Too little non-magnetic spacing — corrupted MWD surveys and a mis-placed wellbore.
• Ignoring inspection class — a fatigued tube passes for one well but fails the next.

A short worked example

For a well with a 10° build to a 9,000 ft lateral, a common steerable string runs a mud motor or rotary steerable at the bit, a non-magnetic collar with the MWD tool spaced above it, near-bit and string stabilizers to control the build, 6¾” drill collars for weight, spiral heavy-weight drill pipe above the collars, and 5” S-135 drill pipe with premium connections to surface. We size the non-magnetic spacing to the survey conditions and inspect the string to Premium class for the build.

Inspected, certified, delivered

Every directional component we rent is inspected to DS-1 / API RP 7G-2 categories, serialized for traceability and available in NACE MR0175 sour-service material where the well requires it. A single directional well usually favors renting; a sustained pad-drilling campaign may justify buying — our rent vs buy guide weighs it. From our network of yards we configure and stage the string to your directional program. Give us the well plan and we’ll quote a complete directional string.