Unique System for Underbalanced Drilling Using Air in the Marcellus Shale

Abstract

Underbalanced drilling offers significant advantages in terms of increased rate of penetration (ROP), less formation damage, reduced lost circulation material, decreased cost of cuttings disposal, and increased production. Underbalanced drilling injects gas into a mud column to lower the overall equivalent mud weight to create a drilling environment where the pressure in the wellbore is kept lower than the fluid pressure in the formation being drilled. Air is the ultimate underbalanced fluid, but diminishes the efficiencies of mud motors, and prevents the use of mud pulse telemetry MWD tools due to the lack of an incompressible fluid. With air drilling, the only fluid injected into the well is a small amount of oil needed to prevent corrosion. Downhole mechanical forces are usually more violent due to the lack of a fluid column for dampening as well as the higher air volumes going through the bottom hole assembly (BHA) for cuttings flow. Common drilling technologies to address air drilling include Electromagnetic Telemetry (EM), mud motors, and downhole air hammers, but reliability issues are particularly prevalent, especially for the EM MWD tools and downhole mud motors. Air drilling has become popular especially in the Marcellus and Utica shale reservoirs in the Northeast United States because of higher ROP and less formation damage. As an example, of the 111 rigs drilling in the Marcellus Shale, 27 rigs are drilling underbalanced and 23 are being drilled with air. A unique drilling system incorporating the use of downhole mud motors, EM MWD, and air hammers has been specifically designed and ruggedized to address downhole shock and vibration encountered in air drilling. Use of this system has resulted in significant reduction of non-productive time (NPT) while drilling with air. This paper will describe how air drilling is being successfully utilized in the unconventional reservoir of the Marcellus shale in the Northeast United States. Drilling fluids and their affect on various pressure regimes will be discussed. The new drilling system will be described and drilling parameters highlighting the differences between mud and air drilling will be provided. Modifications to the BHA to increase reliability will be discussed, and success metrics presented.

Internet of underground things‐assisted performance evaluation for underbalanced drilling telemetry systems

“…Consequently, in this matrix, a vector in the m-dimensional space describes alternate telemetry systems. The matrix is standardized using K formulation to improve the process and reduce the effect of the various measurement units are represented as follows in Equation (5).…”

“…This means one of the effective drilling techniques to control damage for the formation is considered. 4,5 There are a number of natural resources accessible to agricultural lands and surface ecosystems. 6 The Internet of Underground Things (IoUT) is a technology that offers smart petroleum and gas fields, intelligent agriculture fields and intelligent seismic quality checks to effectively use all of these tools.…”

A Comprehensive Overview of the Use of Compressible Drilling Fluids, Advantages and Challenges

“…Air is regarded as the best fluid for use in underbalanced drilling, although it is known to prevent the use of mud pulse telemetry tools due to the absence of an incompressible fluid diminish the efficiencies of mud motors (Maranuk, Rodriguez, Trapasso& Watson, 2014). It is for these reasons that oil is injected in small quantities to prevent corrosion in air drilling.…”

“…Firstly, EM MWD is preferred for the transmission of data from a tool downhole to the surface especially in underbalanced drilling. Secondly, it can be used with compressible fluids such as air and aerated fluids (Maranuk, Rodriguez, Trapasso& Watson, 2014). However, the use of air poses a challenge to both in that it results in intense cross axial and axial levels of vibrations which are generated by the absence of liquid fluid regime.…”

Hydraulics and Well Control Complications in Unconventional Shale Laterals

“…Recently, low gas prices imposed multi-well pads with complex profiles and as a result drilling various sections in one bit run with a negative vertical section is intensely applied (Livingston et al, 2016). Operators achieved drilling records in extended laterals of a mile in a 24-hr period (El Hakam et al, 2014;Maranuk et al, 2014 (Olawoyin et al, 2012). In addition, surface impact of drilling infrastructure and pads necessitates obligatory federal and state permits for water streams in Pennsylvania (Krauss, 2013).…”