A Case History of Casing Directional Drilling in the Norwegian Sector of the North Sea

Bourassa, Kevin Arthur; Husby, Tove; Watts, Rick; Oveson, Dale; Warren, T.M.; Bjorneli, Hans Magnus; Lesso, William G.; Sunde, Frode

doi:10.2118/112560-ms

Cited by 13 publications

(2 citation statements)

References 6 publications

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“…The configuration of the PRSS BHA proposed is a combination of a push-the-bit rotary steerable tool and a straight housing positive displacement motor. This configuration is tested and has delivered good performance in other applications including in coiled tubing 3 and directional casing while drilling operations 4 . To better understand the performance to be expected from this BHA in this application, detailed engineering analysis was performed including assessment of the BHA hydraulics, vibration tendency, side forces, drag and torque.…”

Section: Time Vs Depth -Vankorskoe Field (Horizontal Wells)mentioning

confidence: 99%

Application of Tandem Rotary Steerable-Positive Displacement Motor Bottom Hole Assembly in Drilling Horizontal Wells: Case Study of Three Eastern Siberia Wells

et al. 2011

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The Vankor oil and gas field in Eastern Siberia is predominantly developed using horizontal wells drilled into the upper Yakovlev and lower Nizhnekhet formations. The field development scheme consists of pad clusters resulting in complex well trajectories. Due to the remoteness of the field and resulting complex logistics, any directional drilling technology deployed to deliver the complex trajectories must be robust and reliable. Traditionally, the wells have been drilled with steerable positive displacement motors; in 2008, rotary steerable tools where introduced along with logging-while-drilling (LWD) technology and this provided significant performance improvements in the 8.625 in. and 6 in. sections. To further improve on drilling performance, an engineering study was conducted in 2009 to assess other opportunities for increasing the annual cumulative meters drilled on the project. Several areas of opportunity were identified and prioritized in terms of ease of implementation and expected impact on drilling performance; a key recommendation of the study is the introduction of powered rotary steerable system (PRSS) bottomhole assembly (BHA) in the 8.625 in. section. The PRSS BHA recommended for this application is a tandem rotary steerable-positive displacement motor BHA where a straight fixed housing positive displacement motor is placed directly behind a push-the-bit rotary steerable tool.Various configurations of the PRSS BHA design have been used in other applications including vertical control 1 , performance drilling 1,2 , coiled tubing drilling 3 and directional casing while drilling 4 . In most cases it demonstrated the capacity to deliver better drilling performance in terms of penetration rates and directional control that outperforms conventional directional drilling systems. In the case study wells presented in this paper, about 200% improvement in rate of penetration (ROP) was achieved with an average of eleven operating rig days saved per 8.625 in. well section. The total drilling cost savings realized is estimated to be about USD 1,300,000.00; this is based on an average rig spread rate of USD 40,000.00 per day. These are good results and represent a step change in drilling performance in the field. Some limitations of the new system were also observed in the case study wells, they include inability to deliver consistent dogleg severity (DLS) in excess of 3.5°/30 m, rig hydraulics capacity constraints that limit its broad application, restrictions on bit selection and constraints on the available drillstring rotary speed caused by the unique BHA configuration that in some cases complicates hole cleaning planning. This paper discusses these results and key performance indicators, including aspects of the BHA design, bit selection, hole cleaning management, wellbore stability and drilling practices. A new technology solution to the dogleg severity limitations is proposed: a new generation hybrid rotary steerable tool that can deliver DLS up to 15 o /30 m. It can be incorporated in new tandem rota...

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Section: Time Vs Depth -Vankorskoe Field (Horizontal Wells)mentioning

confidence: 99%

Application of Tandem Rotary Steerable-Positive Displacement Motor Bottom Hole Assembly in Drilling Horizontal Wells: Case Study of Three Eastern Siberia Wells

et al. 2011

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“…Liner While Drilling is advantageous in reducing rig days by solving some downhole problems such as those associated with loss circulation and sloughing shale (Bourassa 2008). Optionally we are able to run liner while doing drilling job with RDM.…”

Section: Liner While Drillingmentioning

confidence: 99%

Application of Reelwell Drilling Method in Offshore Drilling to Address Many Related Challenges

Mirrajabi

Nergaard

Hole

et al. 2009

Asia Pacific Oil and Gas Conference &Amp; Exhibition

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In recent years, operators have been drilling wells in ever increasing water depths. Drilling wells in deepwaters is a daunting task due to both downhole drilling hazards and excessive floating rig packages. Traditionally, these challenging wells are drilled with a low-pressure 21" drilling riser stretching from mudline to surface. A high day-rate gigantic floating rigs with high weight, space, and tensioning requirement is essential to handle this huge and long LP marine riser in deepwaters.Today, the industry is contemplating drilling in water depths of 10,000 ft and beyond, while current equipment can hardly (or even not) take the industry into such depths without changes. The 21" marine drilling riser cannot be pushed much further by existing rigs, and even if the rig could support the riser length and weigh, the riser itself cannot withstand the stresses. Furthermore, if all of these problems are tackled, many downhole drilling challenges are yet to be answered.So, needs for change in current deepwater drilling technology seems to be necessary if the industry is to reach deep targets successfully in deepwaters. Our approach to this problem is changing drilling method; we intend to introduce a newly born drilling technology called Reelwell Drilling Method which is a riserless drilling method by nature and facilitates drilling at any water depth by smaller and less expansive floating rigs, with fewer difficulties.RDM is also promising in delivering closed circulation system which turns it into a competent tool for Managed Pressure Drilling. This feature of RDM can make a big difference in drilling operations in environments with narrow pressure margin which is the case in deepwaters, HPHT, and depleted reservoirs.

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Reducing Risk by Using a Unique Oil-Based Drilling Fluid for an Offshore Casing Directional Drilling Operation

James

Prebensen

Randeberg³

2008

IADC/SPE Drilling Conference

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The conventional drilling approach of employing a drillstring and bottomhole assembly with bit for drilling purposes and eventually running a casing string includes several tripping operations that leave the wellbore open for extended periods of time as an alternative to drilling-with-casing operations where the bottomhole assembly is attached to the casing. This eliminates additional drillstring tripping as drilling and running casing are performed simultaneously. This type of application reduces the number of string trips needed to complete a section, thus saving operational time and associated costs. As the diameter of a casing is larger than a drillstring, this method generally increases the Equivalent Circulating Density (ECD) as pressure losses increase owing to the reduction of the open hole and casing string annulus area. Casing directional drilling operations provide a much narrower drilling window with regards to restrictions in the annulus thus increasing the chances of reaching fracture pressure compared with conventional drillstring operations. To negate the resultant increase in ECD, the rheological profile of the drilling fluid must be designed appropriately. This paper discusses a unique oil-based drilling fluid system weighted with treated micronized barite slurry (TMBS) that has more recently been developed and used successfully in the Eldfisk field of the Greater Ekofisk area, Norway. The drilling fluid system provides low viscosity and a relatively low flat rheology, reduced torque values, and superior sag stability, thus delivering a fluid of low ECD contribution, low-pressure peaks, very effective hydraulics performance and static stability. These exceptional fluid characteristics make the system an excellent solution for drilling sections where the difference between pore pressure and fracture pressure is narrow. This was particularly so in this case where the stability of the fluid from sag potential was crucial for the improved success of the drilling-with-casing operation. Any solids sag onto the latching tools or bottomhole assembly (BHA) with the casing could have caused interference. The system had been used before for differing hole conditions including managed-pressure drilling and extended-reach wells, in high-temperature, high-pressure (HTHP) wells, and now with competence in a casing directional drilling operation. Introduction With this being the first offshore directional drilling work there is limited experience to draw from. To support the deviated drilling with casing operations comprehensive engineering studies were performed to qualify acceptable drilling parameters. This Eldfisk well on the 2/7B platform was the first offshore deviated drilling-with-casing operation ever performed (Fig. 1). The wellbore inclination was increased to a maximum of 69 degrees at the total depth of the second section while drilling with casing. The main purpose of drilling with casing operations is that drilling and casing running operations are conducted simultaneously. By operating in this manner the wellbore is secured at all times from less significant instabilities, and the drillstring tripping time and pipe handling time is dramatically reduced. This is because the BHA is being pulled on wireline for reconfiguration or bit change. The BHA latches into a purposefully designed sleeve in the casing shoe joint. When drilling with casing, the casing is rotated slowly, that is with a rotation per minute rate of less than 30. This rotation assists by "smearing" the drill cuttings into the formation of the wellbore. It helps provide an effective barrier that has been known to prevent the loss of drilling fluid into the formation. This can be quite contrary to conventional drilling operations with a drillstring where the drillstring can aggressively bounce at the wall resulting in the removal of the filter cake in permeable formations. As a consequence the formation could be exposed to the drilling fluid and its higher hydrostatic pressure causing fracturing or a reduction in the formation integrity.

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A Case History of Casing Directional Drilling in the Norwegian Sector of the North Sea

Cited by 13 publications

References 6 publications

Application of Tandem Rotary Steerable-Positive Displacement Motor Bottom Hole Assembly in Drilling Horizontal Wells: Case Study of Three Eastern Siberia Wells

Application of Tandem Rotary Steerable-Positive Displacement Motor Bottom Hole Assembly in Drilling Horizontal Wells: Case Study of Three Eastern Siberia Wells

Application of Reelwell Drilling Method in Offshore Drilling to Address Many Related Challenges

Reducing Risk by Using a Unique Oil-Based Drilling Fluid for an Offshore Casing Directional Drilling Operation

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