Diamond-Impregnated Drillbit Performance in the Lower Basalt Series Offshore the Faroe Islands. A Case Study Based on Basalt Outcrop Testing

Abstract

Exploratory drilling in the Faroe-Shetland Basin of the northeast Atlantic Ocean has been ongoing for several years. One of the greatest challenges of such drilling programs is cost-effectively drilling through the thick layers of Paleogene volcanic rock, which has thicknesses and depths that vary depending on the location of the regional tectonic geography. With the high expense inherent to remote offshore operations, total drilling costs will increase when expected penetration rates and interval lengths are limited due to drillbit inefficiency. An operator planned to drill a second well in the Brugdan prospect, which lies in License 006, Block 6104/21 off the Faroe Islands. The challenge of drilling through a hard, long section of basalt/volcanic sequence presented a great opportunity for investigating and implementing new drillbit materials and design changes to diamond-impregnated bits. A study for materials testing was focused on diamond grit/matrix combinations for wear, durability, and ROP on two representative basalt outcrop columns provided by the customer. The analysis of the physical characteristics of the rock provided an insight of the matrix and diamond combinations for blade material and grit hot-pressed inserts (GHIs) that would offer a reliable product to meet the challenge and drill the long section. Materials testing followed at the drillbit manufacturing facility to find the appropriate diamond-impregnated recipe. A competitive diamond-impregnated bit was developed for the 12¼-in section, resulting in an internal world record and an unprecedented drilling performance in the extremely hard and long volcanic sequence.

Current stability modelling of an incipient San Andres giant landslide on El Hierro Island, Canaries, Spain _ first attempt using limited input data.

“…The used geotechnical parameters for MCMM for the different geotypes are summarized in Table 1. Geotechnical parameters for the different geotypes were extensively searched in the literature (Hoernle, 1998;Apuani et al, 2005;del Potro and Hürlimann, 2008;Rodríguez-Losada et al, 2009;Stow, 2009;Seisdedos et al, 2012;Ferrer et al, 2014;Cai et al, 2015) and adjusted with regards to El Hierro conditions. Parameters of fresh basalts, lava flows and collapse accumulations come from own laboratory investigation with the assumption of critical state mechanics (Muir Wood, 1990) and extrapolation from relevant rock testing cases (Olejár, 2018;Petružálek, 2018).…”

“…Jurassic oceanic crust (142 Ma, van den Bogaard, 2013) in the nearby Gran Canaria Island (210 km to the east) is composed mostly of pillow lavas (Hoernle, 1998) for this geotype the geotechnical parameters from Cai et al (2015) were used. For sedimentary unit I data were used from Stow (2009), who analysed saturated sediments influenced by dynamic effects (seismicity and turbidite currents).…”

Investigation of Filling Phase Percentages on the Performance of WC-Cu Based Hot-Pressing Diamond Bit Matrices

“…Among these, the melting temperature of Cu and Cu-alloys are approximately 900 • C, while Co, Ni, Fe and Mn powders are around 1200-1500 • C. Thus, the formers are usually used as filling phases, and the latters are usually used as bonding phases. Additionally, with the popularization of all-hydraulic drill rig in geological exploration, and the increasing well depth of oil and gas drilling, WC has been altered from the conventional particle reinforced material to a primary content in hot pressed impregnated diamond bit [24][25][26].…”