Coiled Tubing Operational Guidelines in Conjunction with Multistage Fracturing Completions in the Tight Gas Fields of Saudi Arabia

Gazal, Mohammed Al; Abel, Justin Tate; Wilson, Stuart; Wortmann, Henry; Johnston, Bryan Bruce

doi:10.2118/153235-ms

Cited by 4 publications

(1 citation statement)

References 1 publication

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“…In most instances only ball fragments are recovered by the ball catcher (M. Al-Ghazal, 2012). This was a big advantage to the plug-and-perf process which always requires CT milling.…”

Section: Ball-seat Interaction After Fracturingmentioning

confidence: 99%

Sleeve Activation Sleeve Activation in Open-hole Fracturing Systems: A Ball Selection Study

et al. 2012

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During the past decade, the completion technique used in liquid-rich unconventional plays in North America has undergone a transformation. Today, the vast majority of completions in these areas are open-hole (OH) graduated ball-drop fracturing isolation systems. This preferred completion type for horizontal wells is driven by the efficiency gains in fracturing operations and the production gains when compared to previously used completion techniques. Thousands of open-hole fracturing systems are run each year, with a continuously growing stage count.Graduated ball-drop type completions rely on a sliding sleeve activated by a ball dropped from surface. Each ball travels the length of the lateral well to its intended operational depth, at which it meets a mated seat and isolates the wellbore below. Once the ball is in position, the sliding sleeve opens via the hydraulic force on the ball and seat, allowing a fracturing stage to commence. This dual function of the ball-activation and sealing-is of extreme importance for the stimulation treatment process. If the ball fails, it will result in bypassed pay zones and unintentional refracturing of previously stimulated zones. Although sometimes surface pressures can be used to infer ball behavior, often the pressure signals observed at surface cannot guarantee successful ball performance. This paper will present an extensive study of ball performance under pressure for the most common ball materials in the industry. Phenolic, composite and metal alloy materials were explored with the pros and cons for each investigated. In particular three main areas were analyzed: 1) molding, layering and extrusion of material versus inconsistencies in ball performance; 2) ball deformation at high pressure versus pressure required to bring the ball off seat; and 3) comparison of the performance of phenolic, composite and metal alloy materials for ball fabrication and their performance at high temperature.The conclusions from this paper provide operators the necessary information to consider when making completion and ball material decisions in their field operations. In particular, the results of this testing may illuminate some previously unexplainable occurrences in graduated ball sliding-sleeve systems. This testing clarified that not all fracturing balls pumped in horizontal wells perform equivalently under wellbore fracture conditions.

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“…In most instances only ball fragments are recovered by the ball catcher (M. Al-Ghazal, 2012). This was a big advantage to the plug-and-perf process which always requires CT milling.…”

Section: Ball-seat Interaction After Fracturingmentioning

confidence: 99%

Sleeve Activation Sleeve Activation in Open-hole Fracturing Systems: A Ball Selection Study

et al. 2012

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Innovative Process to Ensure Efficient Multiple Stage Fracturing Treatments

Kharrat

Ahmed

Baez

et al. 2012

Abu Dhabi International Petroleum Conference and Exhibition

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Multiple-Stage-Fracturing (MSF) is a common practice today as it allows controlling the stimulation of long intervals, and improves the ultimate recovery of hydrocarbons. Multi-Stage-Frac-Completions (MSFC), designed with Open-Hole-Packers (OHP) and Frac-Ports (FP), are currently implemented by Saudi Aramco to perform such operations in gas wells. The integrity of the OHP and the functionality of the FP are vital for an effective fracturing treatment. During a MSF treatment, the bottom FP is opened first by pressurizing the MSFC to a predetermined pressure. After pumping the first fracturing stage, a ball is dropped to isolate the lower zone, open the second FP with pressure, and enable the second fracturing stage. This step is repeated till all FP are opened and corresponding zones are fracced one after the other. In every step of pressurizing the MSFC, a drop in pressure is automatically interpreted by the assumption that the adequate FP is open and that the MSFC is ready for another fracturing stage. The OHP are also assumed to be holding without performing any downhole checks. Opening the wrong or multiple FP at the same time, having a leaking OHP will certainly lead to undesired results and possible expensive remedial rig interventions. Therefore downhole monitoring is needed to confirm that the MSFC is ready before every fracturing stage. The Fiber-Optic-Enabled-Coiled-Tubing (FOECT) can be used as monitoring system by measuring the Distributed-Temperature-Survey (DTS), which is interpreted realtime to confirm which FP is open, and if OHP are sealing. This paper demonstrates through two case studies how DTS was used to assess the readiness of the MSFC to proppant fracturing treatment. An innovative profiling process in MSFC is proposed to replace assumptions by measured facts, to give client confidence on when to start the fracturing treatment, and to eliminate unnecessary operation by detecting MSFC hardware malfunction.

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Upgrading Multistage Fracturing Strategies Drives Double Success after Success in the Unusual Saudi Gas Reserves

2013

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Open hole multistage fracturing (MSF) technologies have been deployed in Saudi Arabia’s tight gas fields with the objective of maximizing reservoir contact through inducing independent multiple fractures and increasing matrix contribution in both carbonate and sandstone formations. Full achievement of this objective has not been straightforward or quick. While good well productivity was seen from the early wells completed with MSF technologies, several technical issues had to be investigated and resolved when the technology was initially introduced. These issues included mechanical and differential sticking during the technology deployment phase as well as not attaining clear fracture signatures for the subsequent fracture stages after fracturing the first stage during the well treatment operations due to potential hydraulic communication between the fracture stages in carbonate formations. Accordingly, improvement strategies were implemented to mitigate these limitations and realize the full advantage of using MSF technologies in developing tight gas reserves. This paper discusses these strategies and show how they have been successfully utilized to further improve the application of multistage fracturing. Furthermore, the paper addresses a scheme for increasing the success rate for the secondary (contingency) coiled tubing (CT) ball seat milling operations for MSF systems. Also, the paper analyzes the production results for wells completed with MSF technologies and compares them with that of wells completed using other techniques. Additionally, the paper takes a holistic approach integrating the various technical displinces involved in ensuring optimum results are obtained.

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Coiled Tubing Operational Guidelines in Conjunction with Multistage Fracturing Completions in the Tight Gas Fields of Saudi Arabia

Cited by 4 publications

References 1 publication

Sleeve Activation Sleeve Activation in Open-hole Fracturing Systems: A Ball Selection Study

Sleeve Activation Sleeve Activation in Open-hole Fracturing Systems: A Ball Selection Study

Innovative Process to Ensure Efficient Multiple Stage Fracturing Treatments

Upgrading Multistage Fracturing Strategies Drives Double Success after Success in the Unusual Saudi Gas Reserves

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