Britain in Vietnam BBL maintains dominance of drill bit supplies
Scotland's reputation as an innovator in drilling technology is not confined to the North Sea. Several Aberdeen-based entrepreneurs have thrived in Vietnam since large-scale exploration resumed: one of the success stories is Brit Bit (BBL), which was only formed in 1987.
The company specialises in PDC diamond drill bits, and claims to have 80% of the market in Vietnam. Dealing directly with operators, it sold bits to virtually all the companies that drilled off Vietnam in 1994: BP, BHP, British Gas, Lasmo, MJC, Shell and Total.
Even since the US trade embargo was lifted - and most of BBL's competitors are American - the company has maintained its market share, according to managing director Roy Haites. Oil companies appreciate the PDC's proven design and engineering criteria, he says. At OTC '94 the company won a Meritorious Engineering award.
In January 1994 BBL underlined its commitment to Vietnam by setting up an office in Vung Tau with a full-time sales engineer. The company also runs operations in Malaysia, the Middle East and is looking at new bases in Alaska, mainland USA and Colombia.
Design principles
The major difference between BBL's, and all competing products, is the process of manufacture it employs: investment casting.
For every mould a wax model must be invested. To make a mould, a wax model is coated in a slurry of clay and fine silica sand and allowed to dry. A second coat is added and coarse sand is rained onto the wet slurry. This process is repeated a number of times to build sufficient shell thickness to withstand the forces applied during the casting.
The wax and its shell then go through a furnace cycle which melts out the wax and bakes the shell, leaving a perfect impression of the invested wax. It is the wax which controls the quality, repeatability, and accuracy of the final casting.
Two materials commonly used to manufacture PDC bits are steel or tungsten carbide matrix. BBL claims to be the only company using 1990s superalloy. This, allied to the investment casting process allows the company to configure complex internal fluid flow paths which allow for the bit's lateral jet hydraulics and the resultant increase in hydraulic efficiency.
Using lateral jets, BBL claims to have improved ROP by up to 45% over comparable PDC sections. Bit life or footage was bolstered by reviewing PDC cutter shapes and density, i.e. the number of cutters on the bit.
In theory, the greater the quantity of diamond, the longer the life of the product. However, the problem facing all PDC designers is geometric space available on a bit to place cutters and maintain effective fluid cleaning paths. By designing and patenting a unique oval cutter, BBl has increased the usable diamond on a bit by 25% without sacrificing any cutter density.
The product can be refurbished; and since high cobalt alloy is used as the body material, the bit can be brought back to new condition in parent metal, unlike conventional steel body designs relying on a weld. Re-using the same basic bit on different operations clearly brings financial savings.
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