Combining Tools to Increase Efficiency in Challenging Wellbore Cleanouts

Li, Jeff; Lindsey, B. J.; Smith, Simon; Rahimo, Khalid

doi:10.2118/163894-ms

Cited by 6 publications

(1 citation statement)

References 17 publications

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“…10 can be estimated based on the curve regression. Li et al (1999Li et al ( to 2013 and Walker at al. (2000Walker at al.…”

Section: Figure 4 -Comparison Of Measured and Calculated Stationary Cmentioning

confidence: 99%

Overview Solids Transport Study and Application in Oil-Gas Industry-Theoretical Work

Li¹,

Luft²

2014

All Days

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The transport of solids is often encountered in well drilling, completion, well intervention and production processes. The process is affected by many variables and the complexity of the phenomena presents challenges to the field engineer who is trying to determine how these parameters affect solids-transport even if only one of these variables is changed during an operation. In the early stage, solids-transport studies mainly focused on finding the minimum critical velocity to prevent the formation of a stationary debris bed in the wellbore annulus for conventional rotary drilling with mud fluids. Over the past 10 years, the research and development focus has been on obtaining information related to the prediction of the equilibrium solids concentration profile along the whole well path during tripping in, on the wiper trip speed during tripping out, and on the prediction of the hole-cleaning time. Various correlations and models have been developed that would guide the field engineer to design and optimize the hole cleaning process. However, due to the complexity of the process, a comprehensive and proven model still does not exist at present.In this paper, based on 20 years of research experience, the authors present a critical review of the state of the art of previous approaches to studying the solids transport during both drilling and well interventions. It mainly focuses on theoretical studies. An overview of the experimental study of solids transport is given in a companion paper (Li et al. 2014). The methodology used to develop a model to simulate the hole cleaning process is also discussed. To date, completely satisfactory solids transport software, is still not available for the oil industry. Hopefully, this paper will provide a useful and helpful general guide for future research related to this subject and will aid in a better understanding of the lack of previous studies and what issues should be focused on in future research.

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“…10 can be estimated based on the curve regression. Li et al (1999Li et al ( to 2013 and Walker at al. (2000Walker at al.…”

Section: Figure 4 -Comparison Of Measured and Calculated Stationary Cmentioning

confidence: 99%

Overview Solids Transport Study and Application in Oil-Gas Industry-Theoretical Work

Li¹,

Luft²

2014

All Days

View full text Add to dashboard Cite

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Composite: Is Multi-Plug Milling That Fast?

Cromer

Aviles

2014

Day 1 Tue, March 25, 2014

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Multi-stage stimulation by use of composite plugs (CP) for isolation has been in practice for over 15 years in North America. It continues to be a cost effective solution for shale plays requiring hydraulic stimulation of horizontal wells. Currently, there are dozens of plug venders in North America that supplied hundreds of thousands of plugs to the market. In order to perform effectively, plugs must convey down long horizontal wells, deploy at the appropriate depth in a well, hold pressure during a frac, and be removed utilizing conventional wellbore cleanout techniques, which in most areas involve milling with coiled tubing. The milling aspect of designing a plug can be particularly challenging, as it can be difficult to simulate without conducting a full scale test. Additionally, there are many different types of bits or mills to choose from. Thus, testing is required when designing a plug to optimize milling performance. Failure to do so can result in increased milling time and cost, something unacceptable in these tight-economic plays. Mill out testing during the qualification phase is key to the plug performance in real bottomhole conditions. Multiple plugs are used in a single well that ideally will be milled out sequentially. Thus performing a mill test with only one plug may result in an optimistic view of plug milling. There are several important parameters in evaluating milling performance or millability in a test, including: overall millout time, penetration rate, debris size, and stump size. The millout time per plug in a well is defined as the average time taken to mill through a single plug, starting when the mill contacts the top of the plug and ending when the plug‟s anchoring mechanism gives way. This leaves the bottom part, or stump, un-milled. The shape and size of the stump may significantly affect how the debris is conveyed to the next plug as well as the milling of the next plug. Millout time must calculate as an average of no less than two plugs milled in sequence. This paper will describe the best practices for determining the millability of a CP in a multiple plug scenario, and show how milling tests can be used to improve the design of a plug and optimize mill selection. This in turn maximizes the chances of successfully and efficiently removing CPs in the multi-zone treatment application, with the overall goal of improving the economics of these wells.

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Overview of Solids Transport Studies and Applications in Oil and Gas Industry – Experimental Work

Li¹,

Luft²

2014

All Days

View full text Add to dashboard Cite

The transport of solids is encountered in well bore drilling, completion, intervention and production operations. It is affected by many variables and the complexity of the process presents challenges to the field engineer who is trying to determine how these parameters affect solids-transport even if only one of these variables is changed. Historically, solids-transport studies focused mainly on determining the minimum critical velocity to prevent the formation of a stationary debris bed in the wellbore annulus for conventional rotary drilling with mud fluids. Over the past 10 years, the research and development focus has been on obtaining information related to the prediction of the equilibrium solids concentration profile along the whole well path during tripping in, the wiper trip speed during tripping out, and the prediction of the hole-cleaning time. Various computer models have been developed that, to some extent, guide the field engineer in the design and optimization of the solids transport process. However, due to its complexity and incomplete experimental data, a comprehensive, proven and reliable model still does not exist at present. In this paper, based on 20 years of research experience, the authors present a review of previous approaches to the study of solids transport in both drilling and well interventions with emphasis on experimental studies. An overview of the theoretical study of solids transport is presented in a companion paper (Li and Luft, 2014). The basic tests required to collect comprehensive laboratory data in support of the development of a semi-empirical theoretical model to simulate the hole cleaning process, are also discussed. To date there is still no satisfactory solids transport software model commercially available for the oil industry. This paper provides some insight into and understanding of the complexity of the solids transport process, a general guide for necessary laboratory testing and some recommendations for future research related to this subject.

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Combining Tools to Increase Efficiency in Challenging Wellbore Cleanouts

Cited by 6 publications

References 17 publications

Overview Solids Transport Study and Application in Oil-Gas Industry-Theoretical Work

Overview Solids Transport Study and Application in Oil-Gas Industry-Theoretical Work

Composite: Is Multi-Plug Milling That Fast?

Overview of Solids Transport Studies and Applications in Oil and Gas Industry – Experimental Work

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