The “right time” seamless flow of well site data between operators and service companies to speed and enhance decision-making.

In the past, selecting drill bits during well planning hinged to a large extent on the operator’s past experience in drilling offset wells. This practice often was a serendipitous, hit-or-miss proposition, based on the chance that the company’s drilling engineer on the job might have drilled some of the offsets.

The drilling contractor contributed input, and the plan also usually involved a survey of historical bit record databases that indicated how certain bit types reacted in formations likely to be encountered in the upcoming well. The process was more qualitative than quantitative, and often required subjective rather than objective decision-making. Such analogous information, when combined with bit manufacturers’ technical data on specific products, yielded a list of bits or bit types that could be used to drill a borehole as clean and as close to gauge as possible in the least amount of time, given safety requirements and cost limits. In any case, it took considerable time to rustle up the necessary historical data, yet the estimated outcome still remained somewhat in doubt. The introduction of the Drill Bit Optimization System (DBOS™) by Smith Bits was a driving forcing that helped change all that. DBOS is a multidisciplined method for determining the optimum cutting structure, gauge protection, hydraulic con- figuration, and other bit design features for drilling with either roller cone or fixedcutter bits, whether in the conventional rotary mode or with various downhole motor-driven drilling tools, including the turbodrills offered by Sii Neyfor. To characterize the downhole environment of a single well to be drilled, DBOS analysis starts with a thorough reconstruction of expected lithologies, revealed by customer- provided well logs from the closest offset well. The results include a formation analysis, unconfirmed rock strength analysis, and both roller cone and fixed-cutter bit selections.

The operational needs and well plan are then added, including casing points and hole sizes, well directional plot, expected formation tops and mud weights and types, arriving at an optimal minimum cost-per-foot bit program, with options and alternatives. At the highest DBOS service level, Smith prepares contour maps of field “drillability” trends. In this study, multiple wells—typically 8–30 or more—are analyzed to map regional variations in formation drillability on an intervalby- interval basis. This yields a regional applications guide to bit type and bit feature optimization across the field of interest. A very time-intensive service, this DBOS analysis is offered as a fee-based consulting service. At any level of the service, DBOS data are presented graphically to customers in a log-plot form called a Bit Performance Analysis (BPA), which combines numerous parameters that affect rate of penetration (ROP). These include bit record information, directional surveys, real-time ROPs and mud log data, along with rock type and strength data and hydraulic and mechanical energy factors, among others. In bar graph form, the BPA evaluates key bit performance variables over the given drillability intervals, identifying which bit type should be the most successful for drilling through each single interval or over multiple intervals. The analysis also includes both fixed cutter and roller cone bits in cases where either can be applied. Initially, Smith performed DBOS analyzes from its Houston headquarters. It still does today, but fully qualified DBOS specialists, who tend to be petroleum engineers or geologists, are stationed in 14 Smith Bits offices around the world. “A drill bit’s ultimate customer is the rock that it’s going to cut,” said David P. Moran, Smith Bits’ director of applications development. “As a drill bit designer/manufacturer, the better job we do in characterizing that rock-cutting situation, the better we can help determine the correct bit for the job. We use all the data we can bring to bear, be it the rocks, or a particular material for the cutting structure, cutter design or layout, or hydraulic considerations— you name it. To optimize the bit performance, we need to quantify and analyze all aspects of the drilling process.” Initially, Smith bits searches among its existing bit designs in DBOS analyzes, said Moran, who added that DBOS bit selection heuristics are holistic, based on the composite of formation analysis, rock strengths, and offset drill bit conditions, not merely relying on any single factor. “However,” he said, “the DBOS data also are made available to the company’s bit design engineers, so a made-to-order bit can be manufactured quickly to meet special lithologies identified in the BPA.” Also, he noted, DBOS information is used as input for internal Smith Bit design programs such as IDEAS™ and IDEAS II™, which factor drill string dynamics into new bit designs.

DBOS Shows ‘Depth in Specialties’

“From our viewpoint, DBOS skills are a specific discipline,” said Moran. “A DBOS engineer or geologist is experienced in rocks and rock strength, but he doesn’t have the CAD/CAM experience or expertise to design a drill bit. Likewise, a bit designer typically doesn’t have extensive insight in geology. So, with DBOS, two different specialists usually work together to deliver the right product for a particular application. And in postwell analysis, still another specialist, the technical services field engineer, surveys how the recommended bits actually perform, and shares that information, as well. “Smith Bits has considerable depth in each of these specialties, and we believe those involved in DBOS make it the benchmark for systems of this type.” From at least one customer’s viewpoint, DBOS does much to inform—and relieve—field personnel when dealing with the complexities and uncertainties associated with drilling deep, hot and highly pressured wells. Take John Wright, drilling engineer for BP’s South Louisiana asset team. Discussing the successful application of Sii Neyrfor turbodrills in tandem with Smith’s Kinetic diamond impregnated bits in Louisiana’s Tuscaloosa Trend, Wright remarked that single and intermediate level DBOS well analyzes, provided as composite BPAs, are effective visual and technical aids in the field. “You can take that (a BPA) out to the rig…and people can understand something better when they can see it and touch it,” Wright said. “It’s been a tremendous help. It gives them something tangible to work with, and to compare the ROP logs of a whole series of wells.”

YIELD POINT® RT Smith Making Strides Toward Real Time Drilling Optimization

Smith Bits is heavily engaged in tuning its drill bit engineering applications to respond in “real time.” One of them, Yield Point™—in a new form called Yield Point RT™—already is doing so. Additionally, the company expects to add real-time versions of other such programs during the coming months. Real time data is generally accepted to mean measurements or information gathered at the time of its creation and delivered to a user—be it an individual or a software application—in a time frame that allows for meaningful analysis and perhaps even taking immediate steps to correct a process as it occurs. According to David P. Moran, director of applications development for Smith Bits, advances made in 2002 to the industry’s 30-year-old open data standard, WITS (Well site Information Transfer Specification), have made it possible for the company to create and link real time versions of applications to what is now called WITSML. The “ML” extender stands for Extensible Markup Language, which allowsany defined well data—including bit information—to be collected and accessed via the Internet by outside information systems. “What that means is we are poised to begin accepting data from any number of well site data contributors—directional drillers, mud-loggers, formation testers, etc.—to provide meaningful analysis and timely input to ongoing drilling operations,” said Moran. Using the WITSML defined standard data objects and any common internet connection, virtually all information created at or around a well site can be transferred to a common WITSML data store for further retrieval and use by authorized users, starting with the well operator and including the vendors/service providers who contribute their data. Because of the increasing complexity of drilling operations and downhole assemblies, Smith Bits developed the Yield Point drilling hydraulics and hole-cleaning simulation program several years ago to create graphical user interfaces to help drilling engineers specify mud type and mud properties to satisfy rheological models of drill strings and well annuli. It can answer questions about hole cleaning using data on the formations to be encountered. And, using a cuttings transport model, Yield Point can assess potential hole-cleaning problem areas during the well planning stage, rather than having an expensive negative reaction during actual drilling. Once initialized by the user, the program yields graphical simulations of mud properties, flow rates, ROP and other drilling parameters, demonstrating their impacts on bit hydraulics under various hole-cleaning scenarios. Today Smith Bits can link its Yield Point RT program directly to an operator’s well data source in WITSML to provide very close to real time analyzes for hole cleaning and hydraulic optimization, and then make real-time recommendations for improvements, which the operator can apply almost immediately, Moran said. “The idea is that a number of different well site data providers can submit their information into this common data store,” said Moran. “Then, anyone with an analytical application can gain access to it. In Smith’s case, we can hit the data store with Yield Point RT—and soon, with other applications. We then can provide the analysis and return it to the operator in real time to use to improve his operation.” Smith also has developed several mini-programs that can be run by other well site data contributors to map their data into XML format, allowing small companies to compete with large companies who are already XML-compliant, using a data store on the Smith server. It levels the playing field, he said. “We want companies, both large and small, to contribute data easily into the Smith data store,” he said. “So, by moving into this open format, the operator can go back to picking ‘best in class’ among a number of individual services and combining them into a single matrix. That way, they’re not bound to a single turnkey service like those provided by the bigger service companies.” Meanwhile, Smith continues to develop real-time simulation and optimization programs for use with WITSML protocols.