New Cement Systems Developed for Sidetrack Drilling

Al-Yami, Abdullah; Nasr‐El‐Din, Hisham A.; Jennings, Scott; Al-Humaidi, Ahmed S.

doi:10.2118/113092-ms

Cited by 11 publications

(2 citation statements)

References 11 publications

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“…Achieving a successful kickoff plug on the first attempt is a difficult task because of operational challenges that can occur while placing the cement. Oilfield operators have reported many issues that can negatively influence the performance of cement plugs (Al-Yami et al 2008), some of which are presented below.…”

Section: Introductionmentioning

confidence: 99%

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New Technique to Sidetrack Across Hard Formation in North Oman

Al-Salmi¹,

Al-Haji²,

Al-Hamhami³

et al. 2011

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In a north Oman field, it is common practice to cement vertical pilot holes up to the kickoff point. A cement plug is then used to initiate the sidetrack through extremely hard formations. Previously, it has taken several attempts to sidetrack these holes and, in some cases, a mechanical whipstock had to be used.There are challenges when trying to initiate the sidetrack because the formation hardness far exceeds that of the kickoff cement plug. As a result, the sidetracking assembly is repeatedly directed back into the relatively softer cement plug (i.e., vertically). Gravity also plays a role to some extent in bringing the sidetracking assembly back into the vertical hole, increasing the challenge.This paper documents successful implementation of modifications to the slurry design and cementing procedure, as well as the successful use of a side-tracking method/technique in North Oman.The compressive strength of cement has been increased from 5,000 to around 9,000 psi for standard, 17-lbm/gal, Class G cement.The effect of oil-based mud (OBM) contamination has been examined and spacer designs have been improved to help ensure good mud displacement while performing cementing operations.The sidetracking method and tools have also been improved with impressive results. This includes proper selection of the kickoff point based on the drill-speed log of the vertical pilot hole, selecting the correct combination and configuration (e.g., outside diameters of components and angle setting) for the bottomhole assembly (BHA), and using the correct application parameters and techniques while initiating the sidetrack, which is also called "time-drilling." This paper investigates the new techniques applied in detail and clearly illustrates their development. Some case histories are also presented.

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Section: Introductionmentioning

confidence: 99%

“…Conventional cement formulations are used to prepare cement plugs for sidetrack drilling (Al-Yami et al 2008). One of the techniques used to help kicking off is to make the compressive strength of the plug greater than that of the formation, or to increase the toughness of the plug.…”

Section: Introductionmentioning

confidence: 99%

New Technique to Sidetrack Across Hard Formation in North Oman

Al-Salmi¹,

Al-Haji²,

Al-Hamhami³

et al. 2011

All Days

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Drilling Expert System for the Optimal Design and Execution of Successful Cementing Practices

et al. 2010

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Cementing is an important factor in drilling and completion operations. Good cementing practices are required for a proper advancing in drilling and production operations. Successful cementing practices start with the design of effective cement slurries. However, to the best of the authors’ knowledge, there are no standard guidelines to help drilling engineers and scientists in the effective design of optimal cement slurries to be used in different well sections. The objective of this paper is to propose a set of guidelines for the optimal design of cement slurries, by integrating current best practices through a decision-making system based on Artificial Bayesian Intelligence. Best cementing practices collected from data, models, and experts’ opinions, are integrated into a Bayesian Network BN to simulate likely scenarios of its use, that will honor efficient designs when dictated by varying well objectives, well types, temperatures, pressures, and, drilling fluids. The proposed decision-making model follows a causal and an uncertainty-based approach capable of simulating realistic conditions on the use of cement slurries during drilling and completion operations. For instance, well sections and drilling operations dictate the use of the proper cement design which may include the use of specific additives according to the particular modeling scenarios. These include operations on surface casing, top jobs, intermediate casings, cementing in weak formations, squeeze treatment, kickoff and isolation plugs, horizontal, and vertical completions, among others. Potential operational problems that can lead to cementing failures are also discussed. Different methods of investigation and recommendations are presented in detail.

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Tailpipe Disconnects Ideal for Setting Cement Plugs in Complex Wellbores; Procedures and Case Histories Provided

Rogers

Poole

2012

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The primary goal of operators and drilling contractors is to safely, economically, and efficiently drill more holes in less time to enable completion and production operations to begin. However, unplanned events that introduce unexpected and costly delays often occur during the drilling phase. These unplanned events must be dealt with in a timely and effective manner to enable drilling operations to continue. One event type common to drilling operations is the need to set openhole cement plugs for plug back, kickoff, or curing loss-circulation intervals. The time and cost associated with spotting cement plugs directly impacts well operations and is often classified as nonproductive time (NPT) by operators, especially if initial plugs fail to achieve the purpose for which they were set. Placing cement plugs in today’s complex wellbores and the increased costs associated with these operations necessitates the use of plug designs and procedures that have been designed to reduce risk and utilize new technologies and documented processes to achieve the desired results. Reviewing current practices for deploying new technology helps to optimize overall plug cementing operations in both vertical and extended-reach wellbores. However, there are a number of challenges associated with setting cement plugs in an openhole well. Most importantly, drillpipe can become differentially stuck across a lost-circulation zone, and the plug can become contaminated with the intermixing of the mud, resulting in inadequate isolation or insufficient strength. An innovative tool (Rogers et al. 2004) has been designed to meet the challenges associated with setting cement plugs. The tool connects sacrificial/drillable tubing to the drillpipe and allows an operator to trip into the well and spot the cement plug across the problematic zone. Once cement is placed, the tool is disengaged and the operator trips the drillpipe out of the hole, leaving the cement plug and tubing undisturbed. The sacrificial tubing can be drillable; therefore, the operator can drill through the plug or commence other operations, as required. This paper discusses the challenges operators face when setting cement plugs and how risks and NPT are reduced with this innovative plug-setting process and tool. Well examples are documented from case histories to illustrate the success and lessons learned.

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New Cement Systems Developed for Sidetrack Drilling

Cited by 11 publications

References 11 publications

New Technique to Sidetrack Across Hard Formation in North Oman

New Technique to Sidetrack Across Hard Formation in North Oman

Drilling Expert System for the Optimal Design and Execution of Successful Cementing Practices

Tailpipe Disconnects Ideal for Setting Cement Plugs in Complex Wellbores; Procedures and Case Histories Provided

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