The first successes of “shale revolution”, itself associated with the development of horizontal drilling and fracturing technologies, led to a sharp uptick in the horizontal wells. Less than 400 horizontal rigs that existed in 2010 have approached by 2013 the figure of 1,200. The data was provided on the January workshop of SPE Moscow section by Dr. Robello Samuel, Technology Fellow in Drilling & Completions division of Halliburton. The rapid development of this segment challenged the engineering community with advancement of the available technologies.
The expert’s presentation “Technological Advancements to Meet Drilling Challenges in High Angle and Horizontal Wells” focuses on four main drilling challenges: Drillstring Integrity, Hydraulics Management, Wellbore Integrity and Well Placement.
Specifically, notes the expert, Wellbore mechanical friction attributable to pipe rotation or to torque and drag plays a significant role in drilling horizontally as it causes loss of weight transfer, tool failures and wellbore integrity issues. To solve this, the engineers came up with such options as improved torque and drag modeling, provision of additional torque to rotary steerables with mud motors, multipoint sensing and measurements and usage of tools to convert sliding to rolling friction.
Drilling professionals face the issues of also dynamic settling of solids, which leads to zonal isolation problems in particular zones. This kind of challenges may be solved by using mechanical hole cleaning devices, micronized weighting agent and process modelling.
Wellbore integrity may suffer from collapsing shale and carbonates, the issues that lower the wellbore stability. Field workers also often face borehole erosion, rippling, spiraling, hour glassing. Here, engineering solutions include improved bit design and downhole tools, as well as improved salinity control to inhibit shale activity levels.
Sometimes, simultaneous operations (horizontal drilling and fracturing) on adjacent wells may be technically challenging due to wellbore pressures in shale drilling. According to industry experts, 3D-visualization software (SPE 159721) is highly helpful in prevention of fracture interference. Wellbore placement can be improved via maximum reservoir contact by steering precisely in the zone of interest; dynamic, real-time update of the geological model; ahead-of-the-bit predict for rapid generation of look-ahead plan based on updated Geological model.
Although the technology development has positively responded to the needs of horizontal drilling, its future advancement will include areas such as high-speed telemetry, advanced miniaturized sensors and data handling, and predictive analytics, reads the presentation.
In Russia, industry professionals are betting on the Bazhenov Formation, where the conditions are similar to the state of hydrocarbons in shale formations. Same as shale rock, Bazhenov layers have low permeability and segments with developed cracks system, used by Russian producers to lush up on oil. Therefore, efficient drilling must target precisely there segments.
“In that case you need to carefully approach the well planning,” shares Robello his views on the possibility of using horizontal drilling to develop the Bazhenov Formation. “Today, you can drill multi-lateral horizontal wells. But first you need to assess how far you can go,” sums up the expert.
The key task is to plan the well cluster,