Revised Drilling Practices Lead to Lateral-Length Gains in Marcellus Shale
Authors: Carpenter Chris 
Published: January 2019

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 191783, “Drilling Extended Laterals in the Marcellus Shale,” by Joshua Doak, SPE, Matthew Kravits, SPE, Michael Spartz, SPE, and Pat Quinn, Range Resources-Appalachia, prepared for the 2018 SPE/AAPG Eastern Regional Meeting, Pittsburgh, Pennsylvania, USA, 7–11 October. The paper has not been peer reviewed.
A drilling team has focused on increasing lateral lengths in the Marcellus Shale. The team determined which operational practices would need to be revised in order to drill and case laterals in excess of 18,000 ft. During a 12-month period of revised processes and upgrades, the team drilled 34 horizontal wells, each exceeding 12,000 ft in lateral length, which represented the first Marcellus lateral to exceed that length.
Introduction
At the time of writing, the team had drilled more than 1,050 Marcellus wells in the state of Pennsylvania. In the first decade of development (2006–2016), it drilled hundreds of Marcellus horizontal wells with laterals ranging from 1,500 to 11,000 ft. The average lateral length over that period was 3,950 ft. In late 2016, focus was placed on developing the core acreage of the Marcellus field with extended laterals. This change in planning resulted in dozens of wells being scheduled that would feature lateral lengths exceeding 12,000 ft. As a result, the average lateral length increased to 9,450 ft over a span of 200 additional wells drilled starting in 2017.
Throughout the initial years of drilling Marcellus horizontal wells, tools and practices were used that efficiently drilled laterals under 4,000 ft in length. Routine operations included use of rigs with 5,000-psi circulating systems, directional tools with bent housing motors, saltwater-based polymer drilling fluids, and standard drilling procedures. In re-evaluating processes, the team focused on cost per lateral foot (Fig. 1). Increased performance coupled with maintenance of consistent overall drilling costs helped lower the cost per lateral foot.
Comprehensive studies followed by field tests were implemented in preparation for the extended laterals.
Rig Selection
While focusing on what are now deemed as shorter laterals, the team had experienced success drilling with super single rigs because of their versatility and efficient design. The second iteration of a rig fleet to meet the challenges of developing the Marcellus Shale came in the form of high-performance rigs with new enhanced horizontal-drilling capabilities. The team used this style of rig to meet lateral-length challenges successfully from 2010 until late 2016, drilling 805 Marcellus horizontal wells in that time period.
In the spring of 2016, the first 14,000-ft lateral was placed on the drilling schedule for the end of that same year. The rig fleet would need to be upgraded in order to meet the upcoming required changes in lateral length. Size of the rig and equipment became another critical consideration for the rig fleet, because, by then, returning to sites with actively producing wells had become routine, so the upgraded rigs selected would have to fit onto these sites.