BackgroundThe Y-chromosome haplogroup Q has three major branches: Q1, Q2, and Q3. Q1 is found in both Asia and the Americas where it accounts for about 90% of indigenous Native American Y-chromosomes; Q2 is found in North and Central Asia; but little is known about the third branch, Q3, also named Q1b-L275. Here, we combined the efforts of population geneticists and genetic genealogists to use the potential of full Y-chromosome sequencing for reconstructing haplogroup Q3 phylogeography and suggest possible linkages to events in population history.ResultsWe analyzed 47 fully sequenced Y-chromosomes and reconstructed the haplogroup Q3 phylogenetic tree in detail. Haplogroup Q3-L275, derived from the oldest known split within Eurasian/American haplogroup Q, most likely occurred in West or Central Asia in the Upper Paleolithic period. During the Mesolithic and Neolithic epochs, Q3 remained a minor component of the West Asian Y-chromosome pool and gave rise to five branches (Q3a to Q3e), which spread across West, Central and parts of South Asia. Around 3–4 millennia ago (Bronze Age), the Q3a branch underwent a rapid expansion, splitting into seven branches, some of which entered Europe. One of these branches, Q3a1, was acquired by a population ancestral to Ashkenazi Jews and grew within this population during the 1st millennium AD, reaching up to 5% in present day Ashkenazi.ConclusionsThis study dataset was generated by a massive Y-chromosome genotyping effort in the genetic genealogy community, and phylogeographic patterns were revealed by a collaboration of population geneticists and genetic genealogists. This positive experience of collaboration between academic and citizen science provides a model for further joint projects. Merging data and skills of academic and citizen science promises to combine, respectively, quality and quantity, generalization and specialization, and achieve a well-balanced and careful interpretation of the paternal-side history of human populations.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-016-0870-2) contains supplementary material, which is available to authorized users.
The 12-1/4-in. directional application is one of the most challenging applications in North Kuwait. The section requires drilling from the Mutriba (Santonian) to Burgan (Albina) formations through highly interbedded, high-compressive-strength carbonates (limestone and dolomite), sandstones, and shales. In recent years, Kuwait Oil Company (KOC) has tested many different bit designs in an attempt to minimize stick/slip vibrations and maximize the rate of penetration (ROP). This paper presents the technology used to nearly eliminate stick/slip vibrations, leading to a field record (and a consistent performance) for this application, as well as the process used to develop the technology. The interval was drilled using a rotary steerable system (RSS) to maximize wellbore quality and to provide consistent build-up rates (BUR) required. Parameters run in this application are often limited because stick/slip becomes uncontrollable when transitioning through the many formation types. In addition, reactive and stressed caving shales are regularly observed in the Ahmadi and Wara formations drilled during the interval. Special care is needed to mitigate these drilling challenges and to successfully drill the interval with low stick/slip vibrations and high ROP. Using proprietary state-of-the-art design and analysis technologies, a new polycrystalline diamond compact (PDC) bit was designed for use specifically with RSS tools to minimize the vibrations. The solution required a thorough offset analysis before the interval that was presented using the design process. The design process enabled the presentation of a driller's roadmap to be used in conjunction with the new bit to enable a benchmark ROP to be achieved. The use of the newly designed PDC bit produced minimal torsional vibrations, enabling a 62% increase in ROP over the field average. This increased ROP resulted in a savings of USD 90,000, reducing the cost per foot by 33%, as compared to the field average. The bit also came out in excellent condition, enabling future use in similar applications for KOC.
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