Penetration Behaviour of Rock Formations During Exploration Drilling Operations In Turkey

Akun, M.E. (MTA) | Karpuz, C. (Middle East Technical University)

OnePetro 

ABSTRACT: This paper discusses the drillability studies and practical difficulties met at the drilling operations carried out at Zonguldak and Manisa in Turkiye. The drilling operations have been undertaken for both the exploration of new reserves and characterizing the rock units with a higher core recovery. Two holes AK-8 and G-44 at Bartin and Kilimli in Zonguldak have been continuously cored with surface-set and impregnated bits; while the hole at Manisa have been both cored with surface-set bits and non-cored with rock-bits. Some rock and operational properties in relation to drillability have been studied. The technical problems and how they are solved have been studied, cake formation and water loss being the major ones. The operational parameters have been optimized for maximum penetration rates. 1 INTRODUCTION Drilling economy largely depends on the rate of penetration and bit life. Higher penetration rate means less time for completing the job, while longer bit life results in low bit costs and less trip time. So, many effort which aims higher penetration rate and lower bit wear will bring higher economy. This paper presents some part of the results of research conducted on drillability studies at Drilling Site of the General Directoriate of Mineral Research and Exploration in Turkiye. Two different areas are considered, namely the Zonguldak haiddcoal basin and Manisa-Maldan lignite basin in Turkiye. The penetration behaviour of rock formations at Zonguldak are studied at Kilimli G-44 and Bartin AK-8 drill holes, accomplished by Longyear 44 drill rigs. The hole at Maldan is also studied similarly, drilled by Longyear Hydro-55 drill rig. The former rigs have a capacity to drill 1100 meters with AQWL, while the latter can drill 2000 meters with NQWL. The methods of drilling of these holes are discussed in detail. Also, the operations are analysed, giving emphasis on diamond bit performance, drilling parameters and problems encountered. A special attention is given to the Maldan Hydro-55 operations, where non-coring and coring operations are employed together. Finally, comparisons between the three drills are forwarded, together with conclusions and recommendations. 2 CORING OPERATIONS AT ZONGULDAK 2.1. General At two different districts of Zonguldak, namely Kilimli and Bartin, diamond drilling operations for the search of hardcoal have been conducted. At Kilimli, G-44 has attained a depth of 897.15 meters, while AK-8 at Bartin was only 764.30 meters. 2.2. Problems Encountered Water loss was the common problem encountered at both G-44 and AK-8 holes. At G-44 hole, water-loss was observed between 187.00-226.30 meters. The cementing operation carried out twice was not successful and casing became necessary. A partial water loss was also seen after 323.20 meters, and drilling was maintained cautiously with a bentonite- chrome lignosulfonate-caustic soda-CMC mud. At 872.05 meters, the end of NQWL drilling, casing of the hole was accepted to be dangerous due to the fact that in the carboniferous zones casing problems had been encountered in previous holes. Thus, NQWL rods were left to serve as BW rods and the hole was finished with BQWL drill string.

Duplicate Docs Excel Report

Title
None found

Similar Docs  Excel Report  more

TitleSimilaritySource
None found