Optimizing Offshore Infill Drilling: Application of Conductor Sharing and Casing Drilling Techniques

Terimo, Jumasri; Zaman, Hazim Kamarul; Pallath, George; Cherchawankul, Teerasak; Costeno, Hugo; Djohor, Mohamed; Mokhti, Ridzuan; Gonzalez, Luis

doi:10.2118/180579-ms

Cited by 4 publications

References 7 publications

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Buoyancy Force on a Plain or Perforated Portion of a Pipe

Cayeux

Stokka²,

Dvergsnes³

et al. 2021

SPE Journal

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Summary Torque and drag models have been used for several decades to calculate tension and torque profiles along drillstrings, casing strings, and liner strings. Buoyancy forces contribute to the loads acting on the pipe and affect its interaction with the borehole wall. Torque and drag calculations account for these localized effects, as well as the material internal forces, torques, and moments on each side of the contact. When the analysis is applied to a discrete length of pipe, the cross sections at each end do not contribute to the buoyancy forces because they are not in contact with the fluid, except where there is a change in diameter or at the end of the string of pipe. We argue that it is important to check that the models used for solid pipe torque and drag calculations remain valid for sand screens, in particular, the extent to which the buoyancy forces acting on a perforated tube might differ from those on a solid pipe. Because the buoyancy force is the result of the pressure gradient acting on the surface of the pipe, the presence of holes may also influence the buoyancy force. We propose that there are theoretical differences between local buoyancy forces acting on plain or perforated tubes. This paper describes how to calculate the local buoyancy force on a portion of a drillstem by the application of Gauss’ theorem and accounting for the necessary corrections arising from the cross sections not being exposed to the fluid. We built an experimental setup to verify that the tension inside a pipe subject to buoyancy behaves in accordance with the derived mathematical analysis. With complex well construction operations, for instance during extended-reach drilling or when drilling very shallow wells with high buildup rates, the slightest error in torques and drag calculations may end up jeopardizing the chances of success of the drilling operation. It is therefore important to check that the basis of design calculations remain valid in those contexts and that, for instance, sand screens or slotted liners may be run in hole safely after a successful drilling operation.

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Buoyancy Force on a Plain or Perforated Portion of a Pipe

Cayeux

Stokka²,

Dvergsnes³

et al. 2021

SPE Journal

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Successful and Efficient Drill & Drive Conductor Operation in Offshore East Java

Akbar

Tobing

Musa

et al. 2021

Day 3 Thu, October 14, 2021

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Abstracts Conductor setting depth is critical to provide structural support for next drilling sections. The shoe strength must suffice for drilling ahead and avoid any washout and unstable zone. The objective is to design and run conductor smoothly in regards to engineering and operation aspect. Multidisciplinary approach including geotechnical, drilling engineering, and structure, was implemented during planning strategy. The pre-determined conductor setting depth was defined on the maximum mud weight to be used during drilling surface hole section in accordance to the formation strength below the conductor with the purpose of not inducing losses to the formation. Lateral distance between conductor and platform jacket pile was also analyzed to secure the jacket integrity. Anti-collision analysis was performed to prevent collision due to the existence of production well in same platform. Conductor pipe size and specification with some feature was defined to withstand under anticipated load and environment. To determine the way to achieve target depth and the suitability of hammer type, drivability analysis was performed with various anticipated condition. Considering shallow refusal depth, drill and drive was required to reduce shaft friction of soil. Another environmental challenge arise during conductor operation was unable to contain fluid and cutting returns from clean-out process causing return to cover part of the production platform facility. Some of technology were planned to mitigate this challenge. By having comprehensive conductor design, the conductor pipe in all four wells drilled has been successfully installed without any problem on platform jacket integrity and subsequent drilling section. This approach also enabled to efficiency of conductor installation where the number of clean-out and driving run could be reduced. The overflow return challenge could be fully contained by utilizing selfdesigned equipment. The overall operation days of conductor has shown improvement with 1.02 saving days on the last well which equivalent to amount of cost saving around USD 203,500.

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Application of Key Technique in Splitter Wellhead Cementing Enabled Successful and Safe Operations

Lau

Kumar

Thuzar

2021

Day 1 Tue, March 23, 2021

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This paper describes the application of key technique for splitter wellhead cementing of top-hole section in conductor-sharing wells in dozens of development wells in offshore Malaysia. Its objective is to elaborate on the challenges faced during the well planning phase, methodology of cementing technique, cementing slurry design as well as solutions outcome and lessons learnt. Limitations of current software in the industry to simulate the conductor-sharing well cementation and approaches to maneuver through these limitations are also discussed. During the well planning phase, cementing technique to address the risks associated with splitter wellhead cementing such as accidental cementation of dummy string, poor cement coverage in shared conductor, and losses uncertainties were analyzed. The cementing execution results of first batch of wells are examined, i.e. pressure profile, cement returns as well as opportunities for improvement were documented and translated into recommendations leading to eventual success for future well design. The cement slurry design for each casing in the splitter wellhead are also established based on its associated job objectives which is based on the unique approach in splitter wellhead cementing. The establishment of key cementing technique for such an unconventional well construction technology is important in order to ensure continuous success both in cement placement as well as cement slurry design. The best practices are currently being replicated by other major operators in Malaysia for all splitter wellhead cement design. The learnings from the technique are incorporated into the technical standard of Malaysia operator as well to serve as a specific mandated requirement for future operations. An integrated study of wellhead design, drilling practices and cementing technologies enabled a novel methodology to assure long term zonal isolation for the wells and innovation in the cementing approach enable cost savings for the operator as the wells can be drilled in a safe, efficient and cheaper way.

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Optimizing Offshore Infill Drilling: Application of Conductor Sharing and Casing Drilling Techniques

Cited by 4 publications

References 7 publications

Buoyancy Force on a Plain or Perforated Portion of a Pipe

Buoyancy Force on a Plain or Perforated Portion of a Pipe

Successful and Efficient Drill & Drive Conductor Operation in Offshore East Java

Application of Key Technique in Splitter Wellhead Cementing Enabled Successful and Safe Operations

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