Highly Reliable CO2 Laser VIA Hole Drilling Technology by In-site Process Monitoring

This report describes the features of Cu-direct laser drilled hole quality on multi-layer Printed Wiring Boards (PWBs). Cu-direct laser drilling drills the outer copper foil and build-up layer at the same time, which makes it difficult to form a blind via hole (BVH) with high quality because the copper foil has high reflection coefficient for a CO2 laser with wavelength 10.6 μm. Therefore, this study focused on improving drilled hole qualities such as diameter and overhang. First, the influence of laser irradiation conditions on forming BVH and the drilled hole diameter were investigated in detail. Second, a new method employing thermography was proposed in order to evaluate the absorption of copper foil after surface treatment. Third, the effect of mixing fillers into the build-up layer in order to reduce the amount of overhang was shown to be effective both experimentally and theoretically. As a result, it is clear that decreasing the difference in the laser absorption rate of the outer copper foil is an effective means to control the hole diameter and reducing the heat characteristic difference between the outer copper foil and the build-up layer can effectively decrease overhang.

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The First Multilateral Well in Eastern Siberia on the Separated Oil Reservoirs

10.2118/206455-ms ◽

2021 ◽

Author(s):

Ruslan Fanisovich Gataullin ◽

Stanislav Evgen’evich Ter-Saakov ◽

Evgenij Vladimirovich Nikulin ◽

Dmitriy Pavlovich Stifeev ◽

Alexey Vyacheslavovich Filatov

Keyword(s):

Low Frequency ◽

Cost Effective ◽

Drill String ◽

Hole Drilling ◽

Drill Bit ◽

Eastern Siberia ◽

Water Contact ◽

Bottom Hole ◽

Drilling Technology ◽

Equipment Failures

Abstract This article describes engineering and technology solutions developed to successfully construct unconventional and unique horizontal well at the field of Eastern Siberia targeted to two isolated formations with an option to shut-off top Botuobinsky horizon after gas breakthrough and produce oil from underlying Ulakhansky bed further on. As oil-water contact in the lower part of Ulakhansky horizon makes fracturing the well inexpedient, multi hole drilling technology was implemented enabling drainage of the reserves that are far from the main borehole. The main objective of this well is to deplete Botuobinsky horizon subsequently shutting it off and continuing to recover petroleum reserves from Ulakhansky pay zone. Constructing such well is cost-effective, as it requires drilling only one intermediate casing interval instead of two. Accumulated experience of drilling and completing multi hole wells was used to ensure successful well construction; also, geological and stratigraphic data as well as possible complications while drilling Botuobunsky and Ulakhansky formations were analyzed in-depth. The following appliances were selected to meet the objective: –Bottom-hole equipment enabling drilling abrasive formations under conditions of high vibrations;–Special line of drill bits to ensure high ROP and successful sidetracking without additional tripping;–RSS with 152.4 mm drill bit. The goal set by the operating company was achieved through multi-faceted approach to performing the task, efficient cooperation of engineering technical services and continuous monitoring of output data while drilling. All that combined delivered the results listed below: –Sidetracks were carried out in an open horizontal hole without cement plugs and additional tripping for drill bit or BHA.–Minimized bottom-hole equipment failures under condition of increased high-frequency vibrations from bit while drilling hard formations due to implementation of modular PDM with data-transmitting channel.–Minimized bottom-hole equipment failures under condition of increased low-frequency vibrations from drill string with Hard Bending due to improved BHA design and optimized drilling parameters selection.–Liner was effectively run to Botuobinsky and Ulakhansky reservoirs with an option to shut-off the former after depletion and gas breakthrough. This well is the first one targeted at two isolated formations in East Siberia.

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