Shale Play Drilling Challenges: Case Histories and Lessons Learned

Abstract

Shale drilling for both natural gas and hydrocarbon liquids has increased dramatically in North America over the last several years. Shale oil and gas deposits are known to exist all over the globe including Australia and the rest of the Asia Pacific. This paper discusses the requirements for drillpipe in shale drilling applications along with a review of some of the challenges and problems associated with the drillstring in these critical applications. Most wells are horizontal with long departures. Typical wells in the Bakken Shale are 17,000 ft MD, 11,000 ft TVD with a 6,000 ft horizontal reach. Drilling these wells puts huge demands on the drillpipe and rotary shoulder connections and pushes the drilling equipment and rig crews beyond the requirements of typical onshore well construction projects. Many, if not most, of the shale wells require advanced design, double shoulder connections (DSC) on the drillstring to provide the enhanced torsional strength and streamlined connection dimensions required to effectively drill these prospects. The paper presents connection design solutions along with considerations for safe and efficient running procedures. Although, the advanced DSCs are designed to be transparent to normal drilling operations, compared to standard API connections, some problems have been encountered. The paper addresses these running and handling issues and provides guidelines to mitigate these problems. Excessive tool joint and drillpipe body wear have also been encountered in several shale plays. This is discussed, along with recommendations to limit wear. Stick-slip has created drillstring problems on several wells. Stick-slip can cause damage to the drillpipe and, in the extreme, downhole connection back-offs have occurred. The paper looks at aspects of case histories to illustrate these issues and provides lessons learned to improve shale drilling operations in North America, the Asia Pacific and other regions of the world.

GHGfrack: An Open-Source Model for Estimating Greenhouse Gas Emissions from Combustion of Fuel during Drilling and Hydraulic Fracturing

“…16,19 The geometry of wells and hole sizes are taken from Guo et al and Jellison et al for Eagle Ford and Bakken, respectively. 17,20 The rest of the model inputs are the same as those we used in the PSAC model calibration described above (Table S2). We assume the same average injection time is spent in fracturing of each stage (300 ft) in both Eagle Ford and Bakken.…”

“…and through a lateral casing with an average ID of 4 in. 20 The model outputs are given in detail in Table S10. Figure 4a shows the breakdown of the combustion GHG emissions for the most common well design in Eagle Ford according to Guo et al (65% of Eagle Ford wells).…”

Drillstring Oscillations: The Influence of Fluid Loading and Stabilizer Effects

“…Usually, the configuration of the drillstring is a combination of various deformation states. ese irregular deformations and vibrations can lead to the failure of the drillstring itself [5,6] and also cause wear of downhole tools and casing [7][8][9] in contact with the drillstring. An understanding of downhole vibrations and deformations of a drillstring is an important basis for guaranteeing drilling safety for complex structural wells and for providing design support for optimized drilling.…”