Quantifying PDC Bit Wear in Real-Time and Establishing an Effective Bit Pull Criterion Using Surface Sensors

It is useful during drilling operations to know when bit failure has occurred because this knowledge can be used to improve drilling performance and provides guidance on when to pull out of hole. This paper presents a simple polycrystalline diamond compact (PDC) bit wear indicator and an associated methodology to help quantify wear and failure using real-time surface sensor data and PDC dull images. The wear indicator is used to identify the point of failure, after which corresponding surface data and dull images can be used to infer the cause of failure. It links rotary speed (RPM) with rate of penetration (ROP) and weight-on-bit (WOB). The term incorporating RPM and ROP represents a "sliding distance", i.e. the number of revolutions required to drill a unit distance of formation, while the WOB represents the formation hardness or contact pressure applied by the formation. This PDC bit wear metric was applied and validated on a data set comprised of 51 lateral production hole bit runs on 9 wells. Surface electric drilling recorder (EDR) data alongside bit dull photos were used to interpret the relationship between the wear metric and observed PDC wear. All runs were in the same extremely hard (estimated 35 – 50 kpsi unconfined compressive strength) and abrasive shale formation. Sliding drilling time and off-bottom time were filtered from the data, and the median wear metric value for each stand was calculated versus measured hole depth while in rotary mode. The initial point in time when the bit fails was found to be most often a singular event, after which ROP never recovered. Once damaged, subsequent catastrophic bit failure generally occurred within drilling 1-2 stands. The rapid bit failure observed was attributed to the increased thermal loads seen at the wear flat of the PDC cutter, which accelerate diamond degradation. The wear metric more accurately identifies the point in time (stand being drilled) of failure than the ROP value by itself. Review of post-run PDC photos show that the final recorded wear metric value can be related to the observed severity of the PDC damage. This information was used to determine a pull criterion to reduce pulling bits that are damaged beyond repair (DBR) and reduce time spent beyond the effective end of life. Pulling bits before DBR status is reached and replacing them increases overall drilling performance. The presented wear metric is simple and cost-effective to implement, which is important to lower-cost land wells, and requires only real-time surface sensor data. It enables a targeted approach to analyzing PDC bit wear, optimizing drilling performance and establishing effective bit pull criteria.

Evaluation of tribological characteristics of technical oils with fullerene compositions

The paper presents experimental studies of the tribological characteristics of liquid lubricants of various viscosity classes and various groups of operation when using fullerene compositions. Tribological characteristics were evaluated on a four-ball friction machine according to GOST 9490. The use of fullerene compositions in the form of a finely dispersed fullerene powder, pre-dispersed (dissolved) in vegetable high oleic oils, for example, rapeseed, with the subsequent addition of the resulting composition to technical oils of various viscosity classes and various groups of operation, leads to the following positive effect. The anti-wear properties of oils, which are assessed by the wear indicator, increase by 20,0…30,7 %, and the critical load on 18,8…25,0%. These indicators significantly exceed similar indicators when using fullerene fine powders without preliminary dispersion in vegetable oils, where the effect is on the border 11,1…15 %. Fullerene additives do not affect the extreme pressure properties of base oils, which are assessed by the scuffing load. This result makes it possible to state that the way to improve the tribological properties of lubricants by introducing a fine powder of fullerenes into base technical oils is ineffective. The experimental results obtained confirm the hypothesis about the possibility of the micelle formation mechanism in the lubricant under the action of the electrostatic field of the friction surface. The presence of a surfactant solvent (vegetable oil) allows you to "start" the micelle formation process at lower fullerene concentrations and to obtain the effect of increasing anti-wear properties.

Unifed indicator of the wear of plastics for different assessment methods

The possibility of describing the wear of plastics, determined according to international standards ISO 9352, ISO 4649, GOST 11012, DIN 52108, EN 295-3, using a unified wear indicator, which is the loss of the volume of the wear material per unit of friction path, has been studied. It is shown that different methods give close values of the unified indicator of wear resistance.

Wear Analysis of gun barrel drill blade in 1.0503 steel drilling process in Milpro HG12 oil environment with addition of ultra-dispersive copper particles and copper oxides

The paper presents construction solutions for guiding a single-sharp barrel drill blade during drilling deep holes, with an analysis of construction and technological problems for two ways of inserting the drill into the processed material in the first stage of drilling - using a pilot hole or guide sleeve. During the implementation of the technological process of deep drilling of holes with barrel drills using a vertical numerical milling machine FNE 40NC AVIA, the kinematics of the object-tool system (P-N) and other technological parameters affecting the execution of pilot holes in strictly defined technological operations were analyzed. The course of operational tests carried out using two types of cooling-lubricating agents - Milpro HG12 oil without and with the addition of ultra-dispersive copper particles and copper oxides (0.05 ÷ 0.6 µm), Panther GP-1 (PWPH PantherOil Poland) in a ratio of 1 to 100 is characterized. Based on the performed drilling of through holes in 1.0503 steel with EB80 drills with a diameter Dc = 8 mm, made of cemented carbide K15 (WC 94%, Co 6%), the course of wear of the barrel drill blade on the total drilling path Lw = 8000 mm for 112 was determined through holes and Kw geometric wear indicator of the drill bit. The obtained results of wear were compared with the results of tribological tests. with the use of cooling lubricants, under the conditions of friction involving 1.0503 steel with tungsten carbide, of chemical composition as K15. The material and technological conditions of abrasive wear of a particular friction pair are the same as for operational tests of the barrel drill blade wear at deep hole drilling.

Tribological Aspects of Cutting Tool Wear during the Turning of Stainless Steels

The research paper presents the tribological aspects of cutting tool wear during the turning of stainless steels. An experiment was conducted in order to assess the wear of carbide cutting inserts with CVD-applied anti-wear coatings (CNMG 12 04 08 ZSZ and CNMA 12 04 12-KR 3205) and an uncoated ceramic cutting insert (CNGA 12 04 08 T0102 WG 650). The test subject included the following stainless steel grades X20Cr13 (1.4021) and X8CrNiS18-9 (1.4305). The analysis involved the direct wear indicator, VBBmax, and the indirect wear indicator, which was the roughness of machined surfaces and the Ra parameter. Based on the obtained results for both X20Cr13 and X8CrNiS18-9 steels, it was noticed that the best durability was exhibited by the CNMG 12 04 08 ZSZ insert, whereas the worst durability was identified for the CNGA 12 04 08 T0102 WG 650 insert. When analysing the results obtained with the VBBmax direct indicator, it was observed that in the case of each of the insert, most often the course of their wear was of nature similar to linear. Comparing the VBBmax direct indicator with the indirect indicator, namely, the measured Ra parameter, it was concluded that they were convergent. Upon the deterioration of the surface quality, greater values of the selected geometric measure of wear on the flank face were also identified.