Optimize, Sustain and Transform: Drilling Performance Improvements Through 12-1/4" Intermediate Section

Author(s):  
Mohamed Al Alawi ◽  
Mohamed Najwani ◽  
Hamish Walker ◽  
John Wingate
SPE Journal ◽  
2016 ◽  
Vol 21 (02) ◽  
pp. 459-470 ◽  
Author(s):  
Reza Asgharzadeh Shishavan ◽  
Casey Hubbell ◽  
Hector D. Perez ◽  
John D. Hedengren ◽  
David S. Pixton ◽  
...  

Summary With the recent advance in high-speed data communication offered by wired-drillpipe (WDP) telemetry, it is now possible to design automated control systems that directly use downhole data (e.g., pressure) to optimize drilling procedures. This research couples drilling hydraulics, rate of penetration (ROP), and rotational-speed (rev/min) control into a single controller for managed-pressure-drilling (MPD) systems. This novel multivariate controller improves drilling performance during normal drilling operations and enhances safety during abnormal drilling conditions such as unwanted gas-influx situations. New advances in drilling automation have made the closed-loop control of downhole weight on bit (WOB) and drillstring rotational speed (rev/min) possible. This study uses two feedback controllers that control the downhole WOB and rev/min by use of surface data. A multivariate nonlinear model-predictive controller (NMPC) uses downhole and surface measurements to simultaneously regulate the bottomhole-assembly (BHA) pressure and maximize the ROP. For this purpose, NMPC provides the necessary set points for the WOB and rev/min feedback controllers and manipulates the choke-valve opening and pump-flow rates. Controller performance is enhanced by means of a nonlinear estimator that works continuously online with the NMPC and provides the necessary estimated parameter values (such as annulus density, friction factor, and gas influx) for precise and efficient drilling control. The designed NMPC controller has a multipriority approach that is described in the following three scenarios: during unexpected gas influx, the NMPC gives priority to BHA pressure control and attenuates the influx effectively by means of a novel kick-attenuation method that switches the control objective from BHA pressure to choke-valve pressure; during connection procedures when adding a new stand, ROP is stopped and the NMPC focuses on maintaining the BHA pressure constant; and during normal drilling operation, which involves changes in the rock formation and differential pressures, NMPC gives priority to ROP maximization while maintaining rev/min, WOB, and BHA pressure within specified bounds. Preliminary results suggest that this multivariate controller for ROP and BHA-pressure control decreases drilling costs, reduces operator workload, and minimizes risk significantly. Specific improvements in drilling performance include higher ROP, effective kick attenuation, and more-uniform cuttings. The use of a multivariate NMPC allows for better ROP optimization and BHA-pressure control than is possible with the use of two independent controllers. These benefits are demonstrated across the three scenarios mentioned previously. In simulation, this technology delivers significant performance improvements during MPD and furthers the development of automated-driller systems.


1995 ◽  
Author(s):  
Matthias Reich ◽  
P.G. Hoving ◽  
Friedhelm Makohl

Author(s):  
Q Zhang ◽  
J Wang

A study of a modified drill point design with plane rake faces is presented. The critical geometries that uniquely define the drill point design are analysed based on the international standard. The study shows that the modified drill design yields positive normal rake angle on the entire lips and point relieving in the chisel edge region. An experimental study of drilling a high tensile steel using 7–13 mm high-speed steel (HSS) drills with titanium nitride (TiN) coatings has been carried out to assess the new drill point design. It shows that the modified plane rake faced (PRF) drills can reduce the thrust force by as much as 46.9 per cent with an average of 23.8 per cent, as compared to the conventional twist drills under the corresponding cutting conditions, while the reduction in torque is also significant with the maximum of 24.9 per cent. These drilling performance improvements are comparable to those from using the multi-facet drills that were claimed as one of the most heartening drill developments in several decades for drilling force reduction, while the PRF drills can be easily sharpened using the conventional twist drill grinders. The drill-life tests amply demonstrate the superiority of the PRF drills over the conventional twist drills.


MRS Bulletin ◽  
1997 ◽  
Vol 22 (10) ◽  
pp. 49-54 ◽  
Author(s):  
E. Todd Ryan ◽  
Andrew J. McKerrow ◽  
Jihperng Leu ◽  
Paul S. Ho

Continuing improvement in device density and performance has significantly affected the dimensions and complexity of the wiring structure for on-chip interconnects. These enhancements have led to a reduction in the wiring pitch and an increase in the number of wiring levels to fulfill demands for density and performance improvements. As device dimensions shrink to less than 0.25 μm, the propagation delay, crosstalk noise, and power dissipation due to resistance-capacitance (RC) coupling become significant. Accordingly the interconnect delay now constitutes a major fraction of the total delay limiting the overall chip performance. Equally important is the processing complexity due to an increase in the number of wiring levels. This inevitably drives cost up by lowering the manufacturing yield due to an increase in defects and processing complexity.To address these problems, new materials for use as metal lines and interlayer dielectrics (ILDs) and alternative architectures have surfaced to replace the current Al(Cu)/SiO2 interconnect technology. These alternative architectures will require the introduction of low-dielectric-constant k materials as the interlayer dielectrics and/or low-resistivity conductors such as copper. The electrical and thermomechanical properties of SiO2 are ideal for ILD applications, and a change to material with different properties has important process-integration implications. To facilitate the choice of an alternative ILD, it is necessary to establish general criterion for evaluating thin-film properties of candidate low-k materials, which can be later correlated with process-integration problems.


2014 ◽  
Author(s):  
F. Attar ◽  
R. Grauwmans ◽  
O. Ikhajiagbe
Keyword(s):  

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