Development and Application of a Large-Hole Rotary Steerable System: Accelerating New Technology Introduction through Successful Collaboration

Armagost, W.K.; Pafitis, Demos; Wernig, Marcus D.

doi:10.2118/79916-ms

Cited by 2 publications

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“…As discussed earlier, borehole quality plays a key role in affecting the development of point loads. While borehole quality during drilling salt has increased significantly in the past few years through development and application of large-hole rotary steerable systems and concurrent reaming-while-drilling technology [2] we assume a relatively high borehole quality (5% ellipticity), but with a log-normal probability density function (PDF) and a COV of 0.50. It is assumed, for lack of data, that the input random variables are statistically independent, and thus the joint probability density function (JPDF) of these random variables is simply the product of the eight probability density functions (PDFs) listed in Table 2.…”

Section: Random Input Variablesmentioning

confidence: 99%

Probabilistic analysis of borehole closure for through-salt well design

Fossum

Fredrich

2007

Acta Geotech.

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Probability levels, in the form of marginal cumulative distribution functions, are determined for the time it takes salt to contact a casing, which penetrates a salt canopy, and the time it takes the casing to yield once salt has contacted the casing, in support of through-salt well design activities required for deep-water, sub-salt environments. The finite-element method coupled with an advanced reliability method is used to perform the analyses. Randomness caused by uncertainties in salt properties, lithostatic stress, drilling-mud pressure, production temperature, and borehole ellipticity is handled by including statistics and probability distributions for each of these random variables. The advanced reliability method takes full account of the random variables and processes without Monte Carlo simulation, by using a method for assessing reliability statistics that computes response probabilities in a direct and efficient manner. This advanced reliability method falls under the general category of fast probability integration schemes.

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Section: Random Input Variablesmentioning

confidence: 99%

Probabilistic analysis of borehole closure for through-salt well design

Fossum

Fredrich

2007

Acta Geotech.

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“…The Gulf of Mexico has been privileged in having the latest and greatest of this technology available; this is how salt drilling with RSS started in the Gulf of Mexico in 2000 (Aburto and Clyde 2009). However, it was only in 2002 when the Gulf of Mexico and the world started to see the benefits of drilling big hole sizes (Armagost et al 2003) such as 17 ½-in. and 18 ¼-in.…”

Section: Introductionmentioning

confidence: 99%

Efficient and Reliable Vertical Drilling of Top Holes with RSS in Deepwater GOM

Chamat

Isral²

2012

IADC/SPE Drilling Conference and Exhibition

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The requirement for a reliable technology to efficiently drill vertical large tophole sections has increased substantially along with the number of deepwater wells. Inefficient salt drilling with mud motors and high rig spread rates were some good reasons for operators to prefer rotary steerable tools (RSS) in large-hole sections since they became available to the Gulf of Mexico (GOM) in October 2004. As the use of RSS in 26-in. and 24-in. sections is becoming more popular and deeper wells require minimum dogleg severities in top holes, the use and requirements for RSS have taken higher importance.Deepwater wells are drilled through ultrasoft formations in the first 800 ft; additionally, surface conductors are normally set with an inclination at the shoe of 0.5° to 2°. The unconsolidated sediments and inclination at the beginning of the 26-in. section present a challenge to either hold vertical or drill directionally with mud motors and RSS. The combination of the issues resulted in difficulty to verticalize a few wells below the surface conductor.While from 2004 to 2009 84% of the runs were successful, a major study was conducted during the drilling moratorium in the GOM to understand the environmental conditions that were the root cause of the issues described above. The investigation of 58 bit runs with 26-in. RSS performed from 2004 to 2010 in deep water were studied using advanced drilling software to understand and solve the issue of inability to drop inclination and, in a few cases, of unwanted inclination buildup. The advanced drilling software included time-and-depth based replay of the drilling operation, bottomhole assembly (BHA) tendency, BHA vibration models, unconfined compressive strength (UCS), and e-Caliper computations.The study helped in understanding that conductor inclination and instantaneous borehole washout, in the first 800 ft below mudline (BML) due to UCS values as low as 350 psi, hinders the RSS push-the-bit pads from contacting the borehole, preventing a drop in inclination and, in some cases, allowing further inclination buildup. As this study was concluded during the moratorium shutdown, the lessons learned and best practices gathered helped to optimize BHAs, drilling parameters, and drilling practices. Implementation of these allowed all 26-in. RSS runs made post-moratorium to deliver vertical well intervals.

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Development and Application of a Large-Hole Rotary Steerable System: Accelerating New Technology Introduction through Successful Collaboration

Cited by 2 publications

References 0 publications

Probabilistic analysis of borehole closure for through-salt well design

Probabilistic analysis of borehole closure for through-salt well design

Efficient and Reliable Vertical Drilling of Top Holes with RSS in Deepwater GOM

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