Horizontal and Extended-Reach Wells

Since the first horizontal well was drilled in 1929, or since the development of steerable mud motors and measurement-while-drilling (MWD) systems in the early 1980s, the technology used to drill horizontal wells has changed and improved significantly. If steerable mud motors are still mainly used despite the growth of the rotary-steerable-systems market, new technologies with names not even thinkable at that time are now necessary to drill these greater-than-15,000-ft lateral sections with perfect well-trajectory control and placement to maximize production and get the most of the oil in place. Indeed, one now hears about nanodrilling fluids, oscillation tools, automatic steering, cloud computing, artificial intelligence, hybrid and adaptable drill bits, embedded and miniature sensors, and fiber optics.

High-technology products have played a key role in lowering breakeven prices on shale horizontal wells. Even though the idea was suspected some time ago, recent studies have established some correlations between wellbore quality (quantified by various tortuosity indexes) and rate of penetration (ROP), occurrence of vibrations, and production. One understands now better why wellbore quality, especially along the horizontal section, is gaining momentum in the industry. Mindsets are about to change regarding weight on bit, high values not always being the preferred or best recommendation. It is now common to sacrifice some ROP for directional purposes to avoid creating an abrupt dogleg that might compromise the completions to bottom.

Drilling a horizontal well now involves a combination of various and complex technologies and variables that need to be controlled or operated almost at the same time. To overcome friction along these long wells, downhole and surface-oscillation tools are combined to transfer the most weight to the bit. To control the wellbore trajectory and counteract potential rock formation dip effect, automatic steering might be used along with geosteering to minimize tortuosity while staying in the pay zone. Survey management along with anticollision calculations are now recommended to optimize the position and spacing of wells. To select the optimum operating parameters that maximize ROP and ­minimize vibrations and mechanical specific energy, a drilling-data-analytics system at the surface with dashboards must be used.

Drilling has become a complex operation that requires a multitude of tasks to be managed at the same time, making the decision process even more difficult. Not surprisingly, then, drilling automation will gain momentum in the near future to deliver consistent execution and performance safely and with good wellbore quality.

Some of the papers selected for this month’s feature illustrate well the latest improvements to drill these complex wells.

This Month's Technical Papers

Permian Basin: Use of In-Situ Mechanical Rock Properties Improves Completions

Reduced-Friction Centralizers Field-Tested for Ultraextended-Reach-Drilling Completions

Rotary-Steerable System Concept Aims To Increase Efficiency, Reduce Costs

Recommended Additional Reading

SPE 191495 A Practical Approach to Casing-Wear Prediction, Modeling, and Mitigation in Challenging Extended-Reach-Drilling Wells by Weifeng Dai, ConocoPhillips, et al.

SPE 191740 A Method for Calculating More-Accurate Stratigraphic Positioning of Horizontal Wells Using Continuous Inclination and Azimuthal Gamma Ray Images Even While Sliding by Susana Gutiérrez, Halliburton, et al.

SPE 192673 A Breakthrough in Extended-Reach Drilling by Introduction of a Redesigned Drillpipe Connection by Edvin Kvalvaag, ADNOC, et al.

Stéphane Menand, SPE, is the president of DrillScan US, based in Houston. Previously, he held a research position at Mines ParisTech, from which he holds a PhD degree in drilling engineering. Menand has 20 years of experience in the oil and gas industry, mainly as a research-and-development project manager in drilling engineering, more specifically in directional drilling, drillstring mechanics (torque, drag, and buckling), drilling dynamics, and drill-bit performance. He has authored or coauthored more than 25 SPE papers and other technical papers and holds several patents. Menand serves on the JPT Editorial Committee and is an associate editor for SPE Drilling & Completions. He can be reached at

Horizontal and Extended-Reach Wells

Stéphane Menand, SPE, President, DrillScan US

01 November 2019

Volume: 71 | Issue: 11

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