A shale gas play operator in Central China has commenced horizontal well drilling development. Upon completion of multiple vertical pilot or evaluation wells, the shale gas target reservoir zones have been identified and are to be developed with horizontal wells. Due to the difficulties and risks associated with acquiring wireline measurements in horizontal sections, Logging While Drilling (LWD) measurements along with Rotary Steerable Drilling Systems (RSS) are used to provide real time formation evaluation, allow the well to be placed optimally within the target reservoir, reduce drilling risks, improve rate of penetration and help optimize completion design.
An integrated LWD tool and RSS was run for the first time in a horizontal shale gas well. The LWD tool delivers elemental spectroscopy, formation sigma and sourceless neutron along with the conventional triple-combo measurements of gamma ray, density, thermal neutron and resistivity. The system provided:
Improved lithology determination and enhanced formation grain density evaluation from elemental capture spectroscopy. This led to improved porosity determination and completion design
Optimized lateral placement in the best quality sub-layer with near-bit GR and density images
The ability to avoid drilling hazards through real-time monitoring of the drilling parameters available from the LWD tool
Greatly improved ROP through the improved drilling capabilities of the RSS. This minimized the time that the formation was exposed to drilling fluids before measurements were acquired. These measurements provided the information required for the success of the first horizontal drilling in a shale gas play.
This paper will detail the use of LWD measurements and a RSS drilling system for an integrated shale gas solution providing comprehensive petrophysical evaluation, accurate well placement, and drilling efficiency optimization for the first horizontal well drilled in a shale gas play in Central China.