已发表: 05/18/2010
已发表: 05/18/2010
The Marcellus shale play is in the Appalachin basin of eastern North America, the play extends for 600miles. It is one of the biggest unconventional shale plays, approximately 3.5 times larger than the 170mile Barnet formation, which is the most prolific source of unconventional gas in US as of today. The shale is of middle Devonian age and it has been estimated that the play contains about 363 trillion cubic feet of recoverable gas, enough to supply US consumption for at least fourteen years.
In the past, the play was developed using conventional vertical wells that resulted in low production and low returns. As with all the Shale plays in North America the development strategy has changed significantly over recent times. In order extract the hydrocarbons at economically viable rates, horizontal wells are drilled from multi well pads and are completed with multi stage fracture stimulation of the lateral. The rig count in the region has increased in this play during the recent downturn in US gas drilling activity.
Directional challenges in these horizontal wells include, surface pad collision risks, complex 3D well profiles and high curvature rates, considerable geological uncertainty leading to variable landing point targets, directionally challenging formations that result in variable DLS yield rates.
In this paper we will show how breakthrough technology has resulted in 2- 3 fold increases in production rate and decreased drilling cost per foot. Technology deployed was a high dogleg RSS capable of delivering continuous, reliable and repeatable doglegs of up to 15deg/100ft, to improve drilling efficiency. It is noteworthy that all casing/completion strings have been run without incident up until now on these wells drilled with high dog leg rotary steerable system.