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The presence of high nitrogen injection rates through the drillstring represents a challenge for modeling hydraulics inside the BHA, in particular rotary steerable systems (RSS). An algorithm was developed to simulate the downhole pressure across the desired bottom hole assembly (BHA) components for nitrified drilling fluids. This paper captures the main features of the model and its validation process. 

Drilling Performance has improved multifold in the Horn River Basin since the start of activity about four years ago. In its early days, a typical well would take about 40 days to drill from spud to cementing the production casing. A range of improvements has happened over the course of the last four years which have reduced the drilling time by a factor of 3 despite the wells getting more complex. A number of different technologies have been applied in order to bring these improvements. 

Rotary steerable tools are in use for drilling deviated as well as vertical wells. They provide certain advantages over alternative technologies such as bent-housing motors or square motors. Careful analysis of offset data helps to screen suitable candidates for the use of rotary steerable technology. The screening process has several aspects, such as the comparison of time, interval lengths, and rates of penetration in rotation and sliding; and a review of non-drilling time, formation tendencies, and bottom hole assemblies. Rig-based data-acquisition systems provide a good source of offset data. Most rigs in Western Canada use such a system for capturing typical drilling parameters at intervals of every 10 to 30 s. A dataset from such an acquisition system can be quite large. 

In today’s world, drilling is mainly driven by performance efficiency. Every operator strives to reduce the cost of drilling without compromising the quality of the wellbore. A low-quality wellbore can limit the life of a well by compromising the success of subsequent operations such as logging, casing, and fracture treatment. One of the major challenges to wellbore quality in western Canada is directional control. The geological environment makes directional control difficult. 

 Performance improvement creates value. For the driller,this means achieving a better performance with each newhole. But what defines a “better” performance? It iscommon practice to use a few offset wells as a benchmarkof expected performance, but this up-front effort to establish key performance indicators (KPIs) requires specialized resources and a significant financial commitment normally justified on only the largest projects. Others, begun without establishing clear benchmarks, often leave untapped value behind.