Similarity evaluation of stratum anti-drilling ability and a new method of drill bit selection

Considering the stratum anti-drilling ability,drill bit working conditions,drill bit application effect and drill bit economic benefits,the similarity of stratum anti-drilling ability was evaluated by grey relational analysis theory to screen out candidate drill bits with reference values.A new comprehensive performance evaluation model of drill bit was established by constructing the absolute ideal solution,changing the relative distance measurement method,and introducing entropy weight to work out the closeness between the candidate drill bits and ideal drill bits and select the reasonable drill bit.Through the construction of absolute ideal solution,improvement of relative distance measurement method and introduction of entropy weight,the inherent defects of TOPSIS decision analysis method,such as non-absolute order,reverse order and unreasonable weight setting,can be overcome.Simple in calculation and easy to understand,the new bit selection method has good adaptability to drill bit selection using dynamic change drill bit database.Field application has proved that the drill bits selected by the new drill bit selection method had significant increase in average rate of penetration,low wear rate,and good compatibility with the drilled formations in actual drilling.This new method of drill bit selection can be used as a technical means to select drill bits with high efficiency,long life and good economics in oilfields.

Improved Automotive CAN Protocol Based on Payload Reduction and Selective Bit Stuffing

In this research paper, the implementation strategies of automotive controller area network protocol are investigated and the short messaging scheme with selective bit stuffing method to improve the effective utilization of its bandwidth has been proposed. There would be a sharp decrease in the performance of traditional CAN protocol because of considerable increase in the number of ECUs (Electronic Control Units) and infotainment gadgets connected in the vehicle architecture. The demand for safety, emission, diagnostics and comfort norms has steeply increased the number of messages in the 250 Kbps CAN network as the computational power of ECUs has gone up. To overcome this problem, the short CAN method has been proposed and the work is benchmarked with SAEJ1939 Heavy commercial vehicle CAN standard. The Matlab Simulink based short CAN has been modeled and the performance of the proposed system has evaluated using virtual instrument cluster. Experimental results have shown that compared to the traditional CAN, the proposed method has reduced the worst case response time of CAN extended frame from 160 μ sec to 144 μ sec. Selective bit stuffing technique has reduced the impact of bit stuffing over the payload and improved the utilization factor for the CAN bus without affecting the CAN message ID properties. The proposed algorithm has been modeled and simulated using CAN Matlab model Simulink and it has been verified using virtual CAN tool and real time CAN bus hardware.

Anti-drilling ability of Ziliujing conglomerate formation in Western Sichuan Basin of China

The conglomerate rock is usually featured by strong heterogeneity,high abrasiveness,and poor drillability due to its complex composition and texture,which brought a huge challenge for drilling efficiency.In order to guide the drill bit selection and high-efficiency drilling,the physical,mechanical,and drillability characteristics were investigated for conglomerate rock that collected from the lower Jurassic Ziliujing formation in the Western Sichuan Basin of China.The mineral composition,SEM micro-structure,P-and S-wave velocities,uniaxial and triaxial compressive testing,drillability,abrasiveness were systematically tested and analyzed.The mechanical properties and anti-drilling ability of Ziliujing formation were proposed for a typical deep well of S-07,and the distribution characteristics were analyzed.The results indicated that the Ziliujing rock is rich-in quartz and clay minerals,due to the co-existing of strong quartz gravel and weak argillaceous cement,the Ziliujing rock shows strong heterogeneity.The relationships are roughly linear among UCS,drillability,and grinding weight loss with P-wave velocity.The Young's modulus,UCS,internal friction angle,drillability,and abrasiveness meet the Weibull distribution pattern,while only the Poisson's ratio meets the Kernel Smooth distribution pattern.Logging interpretation results reval that the Ziliujing formation has the Young's modulus of 38.61±17.08 GPa,the Poisson's ratio of 0.327±0.006,the internal friction angle of 49.21±11.00°,the drillability of 8.04±1.54,and the abrasiveness grade of 4.32±1.94.The mechanical properties and anti-drilling ability of logging interpretation are in good agreement with the experimental data.The Ziliujing formation is a kind of hard rock with strong heterogeneity,high strength,poor drillability,and medium abrasiveness.Based on the characteristics of Ziliujing formations,the SV516TAUL PDC bit with non-planar cutters was selected for the field application due to the good abrasion resistance,impact resistance,self-sharpening and thermal stability of the non-planar cutters.The field application shows that the average ROP of the new type drill bit in Ziliujing formation is 2.93 m/h,and the average footage is 225.9 m.Comparing with the traditional PDC bit,the ROP of the new drill bit with non-planar cutters has increased by 67.4%,and the footage has increased by 92.1%.The results of this paper can be utilized to guide the drill bit selection and high-efficiency drilling in conglomerate formation.