【系列专题】页岩油气中坚力量：逆境仍需钻井（2）

HIGH-SPECIFICATION RIG FLEET DESIGNED FOR SHALE DRILLING

In today’s performance-driven unconventional environments, operators are seeking new ways to deliver a higher quality and more productive wellbore in fewer days and at a lower cost. Traditionally, rigs operate as an independent machine with all equipment operating autonomously, resulting in a lack of integration, minimal automation and coordination of many third parties. By integrating downhole measurements with surface equipment into AC electrical rig designs and with an extensive portfolio of performance optimization software, wellbore placement and managed-pressure drilling solutions, Nabors has introduced a new way of doing business. This model reduces HSE exposure, increases performance and ultimately improves the economics of challenging extended-lateral wells. Nabors SmartRig fleet features high-specification capabilities, including fast-walking pad-optimal designs that are ideal for shale environments. These rigs also include the Rigtelligent icon-based modular controls operating system, which automates routine drilling procedures and enables more precise and consistent operations. Proprietary performance optimization software can be applied to further improve efficiencies, ROP and precise execution of the well plan. Nabors’ rigs can be directionaland managed-pressure ready, with all necessary software and hardware integrated into the rig infrastructure, reducing rigup and rigdown requirements, increasing reliability and streamlining operations.

CLAY-FREE POLYMER SYSTEM DELIVERS RESULTS

Newpark Resource’s Evolution clay-free polymer system is a high-performance water-based drilling fluid (HPWBF) system that combines a rugged polymeric viscosifier/ shale stabilizer with an effective drilling performance enhancer. An operator sought a HPWBF for a well in Texas’ Angelina and Jasper counties for exploratory HP/HT drilling up to 6,096 m (20,000 ft) total vertical depth. The interval was successfully drilled using the Evolution system, with all logging runs executed successfully. The final temperatures were in excess of 200 C (392 F), with densities of 13.7 lb/gal. In comparative studies in the Permian, using Evolution shortened drilling time from 14 days to seven days and replaced traditional diesel oil-based mud with an HSEfriendly HPWBF while providing equivalent or better lubricity and reduced overall cost. The system is designed to provide thermal stability; reduced torque and drag; high ROP; near-gauge hole; and virtually trouble-free drilling, logging and running casing to total depth.

NEW MOTOR CONTROL DRIVE SYSTEM DELIVERS INCREASED UPTIME

To help oil and gas producers reduce energy costs and increase machine uptime for assets running in high-demand shale applications, Rockwell Automation has released a new drive tool, the Allen-Bradley PowerFlex 755T drive. This drive provides a low-harmonic active front-end structure that helps reduce problems in power distribution lines. It also features a high-performance variable-speed control that’s ideal for top drives, mud pumps and drawworks— offering precise motor control in a compact footprint. The drive’s common-bus system configuration reduces the number of components required and minimizes the footprint for applications like multiwell pad operations, where several drives can be housed in a central location. The combination of a low-harmonic active front-end structure, high-performance control and the ability to share a common DC bus structure to reduce footprint make the 755T well-suited for shale oil and gas applications like drilling rigs, pumping applications, artificial lift systems and multiwell pad operations.

GYRO-REFERENCED MAGNETIC RANGING

Drilling a relief well often involves magnetic ranging operations. In most cases, active magnetic ranging is the preferred solution. Such tools can define the distance and direction to the target with respect to their own inner reference axis. In a magnetically clean environment, the azimuthal magnetic toolface could be used to align this inner reference axis with the world’s northeast vertical coordinates. However, when the ranging tool is in close proximity to the target well, magnetic azimuthal toolface referencing is problematic. To make it possible to drill ahead in the presence of this magnetic interference, the normal industry practice is to run a gyro survey and ranging tool separately in a well. However, due to poorly defined highside reference and azimuth, this may not be sufficient if the wells are near-vertical. A proven workaround to this problem is to combine and align both gyro and ranging systems in one tool string and use azimuthal gyro toolface (instead of the azimuthal magnetic or highside gravity toolface) to define the position of the ranging probe reference axis within the world coordinate frame. Scientific Drilling International owns both gyro and ranging technologies which, when combined and deployed during relief well operations, yield dramatic gains in efficiency in well-to-well referencing.

LINER SYSTEM DESIGNED FOR LONG LATERALS

Longer laterals equate to increased production for shale drillers. As part of a well construction design for long laterals, a liner often is installed in one of these laterals. This installation typically requires increased torsional and compressive strength from the running tool to get to total depth. The Powerscrew Liner System from Seminole Services was designed to effectively address this demand. The system’s setting tool uses both compression and torsion while setting the liner top. As a result, these loads transfer more easily to the liner during run-in without the need for a special adapter. Another challenge presented by long laterals is the need to rotate and circulate during liner deployment. The system meets this challenge by providing the rotation and circulation necessary for today’s well construction. In addition, the system’s modern expandable design delivers a step change in reliability. Today’s operators do not hang liners. Liners are worked into the lateral section with compression and torque and then set to engage the intermediate casing.

DOWNHOLE AUTOMATION IMPROVES UNCONVENTIONAL ROP

When cost per barrel becomes an issue, drillers must grab what is available to improve productivity. The Tomax Anti Stick-slip Tool (AST) represents an interesting development in this respect. The spring characteristics of a regular drillstring tend to cause significant distortions in the delivery of power to the bit. Because the bit also is resting on the same surface it is about to remove, it will easily lose its cut when the transfer of weight gets erratic. The AST responds to torsional change within a response time of 5?100 of a second and regulates the axial loading to maintain a steady torsional loading and cut. The continuous loading by the AST also reduces the risk of impact loading and premature spalling of the bits’ cutting edges.

NEW PDC BIT DELIVERS INCREASED PERFORMANCE IN HARSH ENVIRONMENTS

Operators have remarkably increased the energy they run through their bottomhole assemblies seeking higher performance out of their drillbits. Ulterra’s new XtremeParameter (XP) polycrystalline diamond compact (PDC) bits are built for the operator seeking greater performance through increased drilling parameters like weight on bit and the use of high-torque motors. As rig components, drillstrings and downhole tools have been redesigned to increase output over the last 18 to 24 months, Ulterra was developing and testing bit concepts to account for them. These now-proven concepts were brought together into the XP product line. By redesigning body and blade geometry, implementing cutter reinforcement, and using an optimized material selection process, the XP line of drillbits has improved. Ulterra is releasing its XP line of PDC cutters with the redesign of the drillbit. Through a process of material optimization and testing, XP cutters are proven to take greater force with less damage compared to previous generations, improving impact resistance by nearly 20%. With this new XP product line Ulterra is able to extend the life and reliability of PDC bits in the harshest drilling conditions without sacrificing performance in other areas. Oil and gas drilling will keep evolving at an ever-expanding rate.