Operator started evaluating the shale gas block in Central China since Dec 2010. During exploration and appraisal phases, 3 horizontal wells were drilled. The challenges were hard, abrasive, kicks, losses, stuck pipe, over pressure, high formation dip, faults, and high stratigraphy uncertainty. As a result, it was unable to achieve performance drilling with conventional motor BHA, difficult to run casing, and multiple geological side-tracks were required. Wells were exceeding the AFE curves. Average well duration was 220 days.

This paper will feature the challenges and lessons learned and the unconventional approaches that were employed. Four key categories of the process were identified:

Emerging technologies were hybrid and more robust rotary steerable system, real time ROP optimization, high resolution real time LWD image data and high telemetry rate MWD. Drilling and best practices adopted were MPD Drilling, hole cleaning, high dog-leg-severity curve with smoother borehole, and low cost rotating BOP with higher RPM. In the absence of 3-D seismic data, 2-D seismic data combined with LWD data were used. Integrated Operations & Innovative Commercial Contract with local drilling service contractors had made a big impact in terms of faster well delivery and overall cost saving. Another step change was the performance based commercial contract which helped to attain the ultimate goal that meets both HSE and time requirements.

During first half of 2013, 5 horizontal wells were completed, 2 were Top Quartile and 3 were Best-In-Class. Some highlights were zero geological side-track; double footage drilled per day and significantly reduced drilling cost. Average well duration was 120 days.

The accomplishment has a big impact on drilling schedule sequence. Longer horizontal wells will be planned with greater confidence as results of predictability and repeatability.

The paper will conclude with learning curves summary and compare them to the peer. The team believes that this is a big step towards delivering Best-In-Class wells in complex geological structure. The next step is to realize the ambition of factory drilling at further reduced cost to un-tap the unconventional in Sichuan and to bring cleaner fuel to Central China as a replacement of coal.

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