An Integrated System Approach to Wellbore Cleanouts With Coiled Tubing

Radovan, Rolovic; Weng, Xiaowei; Hill, Stephen H.; Robinson, Geoff; Zemlak, Kean; Najafov, Jeyhun

doi:10.2118/89333-ms

Cited by 19 publications

(5 citation statements)

References 23 publications

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“…Based on caliper logs post-descaling operations, blasting the liner and perforations with beads to ensure adequate scale removal to the wellbore inside diameter and improve injectivity across all perforated intervals. 4. Final stimulation will be contingent on post-well cleanup.…”

Section: Warm -Upmentioning

confidence: 99%

Innovative Integrated Procedure for Scale Removal in Khuff Gas Wells in Saudi Arabia

et al. 2012

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Many Khuff gas wells have been experiencing inorganic scale deposits: iron sulfide, iron oxides and calcium carbonate, which are causing weak production and poor wellbore accessibility. The scale problem requires a prompt solution to meet Saudi Aramco gas production objectives.The history of scale removal trials in Khuff gas wells in Saudi Arabia included the mechanical removal with Coiled Tubing (CT), and the chemical dissolution with acid and/or other scale dissolvers pumped through CT or bullheaded. All these methods failed to provide the expected outcome and some jobs resulted in major operational failures like stuck pipe, pinholes, H 2 S release at surface, and formation damage. As a result of these failures the descaling jobs were put on hold by Saudi Aramco many times between 2007 and 2010 with no significant progress made until the 2 nd half of 2010.A project was launched to establish an innovative descaling procedure aimed at a safe and effective scale removal. The integrated solution starts with the temporary isolation of the reservoir to eliminate gas and H 2 S returns at surface, enable a "closed system" cleanout with safe solid handling at low choke pressure, and minimum surface testing equipment. The second step is based on mechanical removal that eliminates long soaking time and/or H 2 S generation during chemical dissolution. For that, a high pressure jetting tool designed and proved to remove hard scale is deployed on CT. The critical step of scale cleanout to surface is optimized with the use of large outside diameter CT string and special high temperature gel to ensure efficient lift and eliminate the risk of stuck pipes. The major enhancement to this project is the ability to monitor in real-time bottom-hole pressure and temperature, annular solid concentration, and the high pressure jetting tool efficiency with a fiber optic enabled coiled tubing string. The whole process resulted in a controlled and optimized scale removal treatment.Multiple case histories are presented in this paper to demonstrate the successful implementation of the integrated solution, which is then selected as the only approved method for scale removal in Khuff gas wells.

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Section: Warm -Upmentioning

confidence: 99%

Innovative Integrated Procedure for Scale Removal in Khuff Gas Wells in Saudi Arabia

et al. 2012

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“…The cuttings slurry must have enough cuttings suspension capacity between injections to avoid the risk of cuttings settling during suspension or the solid-laden slurry must be displaced with a solid-free fluid before the next injection. Again, much progress has been made in the drilling industry for hole cleaning [27][28] and in the chemical industry for two-phase suspension flow 29 . Advances have been made recently to ensure adequate suspension in CRI operations by modifying the models developed in the above mentioned industries and validation with slurry rheology and suspension tests.…”

Section: • Cuttings Suspensionmentioning

confidence: 99%

Increased Assurance of Drill Cuttings Re-Injection - Challenges, Recent Advances and Case Studies

Guo¹,

Thomas²,

Adriana³

2004

Proceedings of IADC/SPE Asia Pacific Drilling Technology Conference and Exhibition

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fax 01-972-952-9435. AbstractThe handling of drill cuttings and wastes is both an environmental and economic issue in drilling operations. With ever-tightening environmental regulations and the green operation initiatives of operators, drill cuttings re-injection (CRI) into a subsurface geology often is the preferred option as it allows operators to achieve zero discharge since oily cuttings are returned to their place of origin.When the technology started about a decade ago, injection into a single well had a maximum slurry volume of approximately 30,000 bbl. Now, particularly in very large projects, several million barrels of slurry may be injected into a single well. This represents more than a 1000 times the volume of a typical hydraulic fracturing job or more than 100 times that of those earlier cuttings re-injections. In some cases, the success of the CRI operation is critical because there either are no back-up options or the economic and environmental impacts are too significant. This paper describes the challenges faced in CRI projects, along with recent advances and experiences gained in tackling these challenges through modeling, cuttings slurry and operational procedure design, monitoring and verification. For example, much progress has been made recently in slurry rheology design and operational procedure selection such as suspension/displacing to avoid loss of injectivity and to maximize disposal capacity and minimize HSE issues.The authors also will present a risk-based approach, which integrates deterministic software and tools, available data, knowledge and experience, for modeling of geological and operational uncertainties and potential risks to increase the quality assurance. Case examples will be presented to illustrate the value of this integrated approach. Best practice guidelines and recommendations will be provided on data collection, design and engineering, operation and monitoring.

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“…This results in severe damage to the formation and significantly reduces hydrocarbon production. Hence, it is imperative to study the magnitude and effect density of cuttings in addition to other controllable parameters to optimize cleanout efficiency [5,6,7,8].…”

Section: -Introductionmentioning

confidence: 99%

Experimental Study for Assessment of Cutting Density Effect on Hole Cleaning Efficiency in Inclined and Horizontal Wells

Mohammed¹,

Almahdawi²

2020

IJCPE

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The poor hole cleaning efficiency could causes many problems such as high torque, drag, poor hydraulics and pipe stuck. These inherent problems result in an avoidable high operation cost which this study tried to address. In this study, the effect of cutting density on hole cleaning efficiency in deviated and horizontal wells was investigated. Experiments were conducted using 40 feet (12 m) long of flow loop made from iron and PVC. However, the test section was made from PVC with (5.1m) long and (4” ID) for outer pipe and (2” OD) inner pipe. The cutting transport ratio (CTR) was determined from weight measurements for each test. Cutting Transport Ratio has been investigated for effects of the following parameters; flow rate, cutting size and density, yield point of drilling mud, and inclination angle. Once the setup was positioned at the desired inclination, the cutting was transported for 3 minutes at a constant flow rate and yield point. The amount of cutting removed during each test was thereafter weighted to determine cutting transport ratio CTR. The results obtained from this study showed that the cutting density has a slight to moderate effect on hole cleaning efficiency. Also, there was a remarkable improvement in the cutting transport ratio annular velocity and hole inclination angle was increased. However, the yield point (Yp) was negligible at maximum values of annular velocity. Therefore, at high value of yield point the cuttings with large and medium size were transported more than small size. This case is inversed at a low value of Yp. Moreover, for all sizes the heavy cutting transport less than light cutting. Finally, the critical angle was recorded between 65o-75o. Sigma plot 12.5 program has been used to graph all figures in this paper.

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An Integrated System Approach to Wellbore Cleanouts With Coiled Tubing

Cited by 19 publications

References 23 publications

Innovative Integrated Procedure for Scale Removal in Khuff Gas Wells in Saudi Arabia

Innovative Integrated Procedure for Scale Removal in Khuff Gas Wells in Saudi Arabia

Increased Assurance of Drill Cuttings Re-Injection - Challenges, Recent Advances and Case Studies

Experimental Study for Assessment of Cutting Density Effect on Hole Cleaning Efficiency in Inclined and Horizontal Wells

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