Wyniki wyszukiwania - Biblioteka Nauki

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Experimental study of layouts of PDC cutters in core bit drilling

100%

Buitrago Gomez L. A. , Miska S. Z. , Ziaja M. B.

AGH Drilling, Oil, Gas

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2016

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tom Vol. 33, no. 2

341--360

EN

Over the past two decades, various single cutter force models have been developed that consider formation properties and bit characteristics. These models have been extensively used to describe the interaction of a Polycrystalline Diamond Compact (PDC) bit with formation rocks; however, their use to predict bit drilling efficiency is usually inadequate. There is an ample of field evidence that the density and layouts of PDC cutters affect drilling efficiency. Still, however, there is no reliable model of the PDC bit performance allowing determination of these bit design features for a specific bit's applications. In order to better understand the relationship between rock properties and PDC cutter layouts for different bit applications, laboratory drilling tests were performed with PDC core bits. The concept of an eight-blade PDC core bit was used to build a bit with a common body and replaceable heads. Core-bit design features such as: bit, cutter size, and cutter geometry were constant. In this study, the full-scale test rig facility at the University of Tulsa was used to obtain consistent data for six different layouts of PDC cutters. Operating parameters, such as the rate per minute (RPM) and weight on bit (WOB), were varied and performance parameters (rate of penetration (ROP) and bit torque (TQB)), were measured at each time step with the frequency of 10 Hz. The ROP were calculated as a function of bit displacement over time. All operating parameters were recorded as part of the data acquisition platform. Depth of Cut (DOC) was calculated from ROP, and the average WOB and TQB were estimated at each depth of cut. Tests were performed on two different rocks: Bedford and Carthage Limestones. For the purpose of comparing performance among different cutter layouts, we experiment with a maximum of four different depths of cut, which corresponded to four different weights on bit. The tested layouts allowed a constant maximum DOC per cutter of 0.25 in. Water was the drilling fluid for the entire experimental phase. The results showed that under the same drilling parameters, the cutter layout plays a key role in drilling efficiency. Strong linear relationships were found between DOC, WOB and TQB at different conditions that were characteristic of the specific bit design. Also, the PDC cutter layouts affected the relative drilling performance differently for different rock properties.

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Pobór i opróbowanie powierzchniowych, silnie uwodnionych osadów jeziornych o nienaruszonej strukturze-uwagi metodyczne i stosowany sprzęt

86%

Tylman W.

Przegląd Geologiczny

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2007

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tom Vol. 55, nr 2

151-151

EN

This study presents some remarks about coring and sectioning cores of recent lake sediments. Effective coring of such sediments is not easy because they are very loose (water content usually exceeds 90%]. Precisely taken core should consist of near-bottom water and undisturbed sediment column. The most widely used are gravity corers which are simple in construction and operation. The gravity corer presented here is additionally equipped with percussion system to improve penetration into the sediment. It enables to take cores 94 mm in diameter and up to 90 cm in length. The corer with rubber stopper blocked is lowered through the water and pushed into the sediment. While retrieving the core, the stopper settles into the top of the core tube. At the surface, the plug is inserted into the bottom of the core tube. After collecting, the core should be extruded and sectioned. A device presented here enables to divide the core into short intervals [0.5-1 cm]. The core is extruded upwards and samples can be collected from the tray placed on top of the tube. Both the corer and the extruder are relatively small and light. This equipment have been used in the Department of Geomorphology & Quaternary Geology at Gdańsk University for several years. So far, cores from more than 60 lakes of various depths [up to 50 m] have been successfully taken.

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Core recovery criterion – a new optimization method of geological information quality in the geological conditions of the Grodziec Syncline Area

72%

Janc D. , Wiśniowski R. , Stryczek S.

Gospodarka Surowcami Mineralnymi

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2016

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tom T. 32, z. 4

91--108

EN

The increasing requirements for the quality and amount of geological information induce the development of new technological solutions. The authors present the optimization of the coring method for a newly defined criterion of maximum geological information quality. It enables the efficiency of works to be improved without investing in new specialist and expensive equipment. The statistical classification methods commonly used in medicine and the economy were used for analyzing the homogeneity of the drilled rocks. The quadratic discriminant analysis (QDA) and the Naive Bayes classifier method turned out to be most efficient, therefore they were selected from among other methods differing in the way the classification rules are built. The newly defined criterion of maximum geological information quality and the mathematical model of maximum core recovery allowed the amount and the quality of recovered rock material in the geologic conditions of the Grodziec Syncline to be incresed. The control of the process relied on detecting phenomena responsible for core damaging, i.e. erosiveness of drilling mud, mechanical damaging due to jamming in the core barrel and unstable operation of the core bit downhole. The analysis revealed that the main factor influencing the lower recovery of cores is mechanical damaging due to jamming in the core barrel. For the sake of controlling the core recovery, the authors defined and used the jamming index which defines the effect of weight on bit on momentary rate of penetration. The efficiency of this method was proved by a test performed in industrial conditions while drilling a successive wellbore in the Grodziec Syncline. This paper was written on the basis of own experience and analyses performed by the authors while conducting works in the Grodziec Syncline in the South West Poland.

PL

Coraz większe wymogi co do jakości i ilości informacji geologicznej wymuszają ciągłe udoskonalanie technik i technologii ich pozyskiwania. W artykule tym autorzy przedstawili metodę optymalizacji procesu rdzeniowania dla nowo zdefiniowanego kryterium maksymalnego uzysku rdzenia, które jednocześnie jest kryterium maksymalnej jakości informacji geologicznej. Pozwala ona na poprawę efektywności prowadzonych prac bez konieczności inwestycji w nowy, specjalistyczny i drogi sprzęt. Do badania jednorodności przewiercanych stref zaadaptowane zostały powszechnie stosowane w medycynie i ekonomii statystyczne metody klasyfikacji. Spośród przeanalizowanych metod różniących się sposobem budowy reguły klasyfikacyjnej największą efektywnością wykazała się metoda QDA (quadratic discriminant analysis) oraz naiwny klasyfikator bayesowski (Naive Bayes classifier). Zdefiniowane nowe kryterium maksymalnego uzysku rdzenia oraz opracowany matematyczny model uzysku rdzenia pozwolił na zwiększenie ilości, jak i jakości uzyskanego materiału do analiz, w warunkach geologicznych synkliny grodzieckiej. Sterowanie procesem polegało na detekcji zjawisk niszczenia rdzenia, tj. erozyjnego oddziaływania płuczki wiertniczej na rdzeń, mechanicznego niszczenia rdzenia na skutek klinowania się go w aparacie rdzeniowym, a także niestabilnej pracy narzędzia na dnie otworu. Analiza wykazała, że głównym czynnikiem wpływającym na zmniejszone uzyski rdzenia jest mechaniczne niszczenie na skutek klinowania. Do kontroli wartości uzysku rdzenia autorzy zdefiniowali i wykorzystali wskaźnik klinowania przedstawiający wpływ nacisku osiowego na chwilową prędkość wiercenia. Skuteczność opracowanej metodyki potwierdził test przeprowadzony w warunkach przemysłowych, podczas wiercenia kolejnego otworu na obszarze synkliny grodzieckiej. Artykuł ten powstał na podstawie własnych doświadczeń i analiz przeprowadzonych przez autorów podczas realizacji prac na obszarze synkliny grodzieckiej w południowo-zachodniej części Polski.

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Komplikacje wiertnicze podczas rdzeniowania oraz metody wpływające na zwiększenie uzysku rdzenia na przykładzie wierceń na obszarze koncesyjnym KGHM Polska Miedź S.A.

72%

Janc D. , Żuromski Z. , Zwierzchowski W.

Wiadomości Naftowe i Gazownicze

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2011

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tom R. 14, Nr 4 (156)

4--10