Fiber-Optic Monitoring: Stimulation Results From Unconventional Reservoirs

Holley, Eric; Kalia, Nitika

doi:10.15530/urtec-2015-2151906

Cited by 19 publications

(3 citation statements)

References 13 publications

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“…Many fiber-optic case studies of plug-and-perf completions show examples of stages where lack of isolation is observed (Holley and Kalia 2015;Raterman et al 2017;Sookprasong et al 2014;Spain et al 2015;Ugueto et al 2015;Wheaton et al 2016). However, none of these references include discussion or any information relating these observations to fiber failures.…”

Section: Current Industry Observationmentioning

confidence: 99%

One Stage Forward or Two Stages Back, What are We Treating? Identification of Internal Casing Erosion During Hydraulic Fracturing - A Montney Case Study Using Ultrasonic and Fiber-Optic Diagnostics

White

Friehauf

Cramer

et al. 2020

Day 2 Tue, October 27, 2020

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Plug-and-perf multi-stage hydraulic fracturing completions in unconventional reservoirs rely upon complete hydraulic isolation from the previous stage to ensure effective treatment of the active stage. Failure to isolate stages can be a result of partially set plugs, plugs set in wellbore debris or deformed casing, unqualified pressure/temperature rating of plugs, etc. This paper presents a case study with field examples where unexpected casing erosion occurred at the setting depths of the dissolvable frac plugs during hydraulic fracturing and subsequently resulted in loss of inter-stage isolation. A 12-well, 4-layer, cube pilot was designed with permanent fiber optic cable to collect Distributed Acoustic Sensing (DAS), Distributed Temperature Sensing (DTS) and Distributed Strain Sensing (DSS) data as well as downhole pressure gauges for development insight and future completion optimization. The cable was mapped, and oriented perforation techniques placed entry holes opposite the fiber along the wellbore, and no loss of communication was observed during perforating operations. However, fiber optic signal was lost during hydraulic fracturing operations on one or more stages in all four instrumented horizontal wells. Real-time DAS/DTS analysis indicated the fiber breaks were consistently occurring below the lowermost perforation cluster in the stage, at or very near the frac plug setting depth. Step-down tests were also performed and showed significantly enlarged effective treating area. Based on this observation, post-frac downhole imaging tools were deployed to investigate potential casing and perforation erosion. Downhole imaging data clearly showed the casing was severely eroded at several locations. Additional interrogation of the damage with respect to plug design components indicated that damage always occurred near the plug sealing element. By integrating the analysis of DAS/DTS, step-down tests and ultrasonic imaging, it was determined that the frac plug bypass is creating a loss of casing integrity at the plug set location. Casing integrity loss resulted in multiple fiber optic cable breaks and lowered the ability to evenly distribute slurry into treatment clusters. Fiber optic data analysis showed that 50% of the larger OD dissolvable frac plugs had bypass compared to 100% bypass for the smaller OD high-expansion dissolvable plugs. To establish key patterns and identify critical variables that influence stimulation effectiveness, it is important to obtain several different diagnostic datasets and perform an integrated evaluation using all available information. This study also reinforces the need for operators and manufacturers to work together to design and qualify frac plugs against realistic downhole conditions, particularly in areas with potential casing deformation issues. Industry innovation is required to enable fracturing operations to continue through deformed casing. This includes advancing equipment, tools, and techniques for plug-and-perf and other multi-stage completion methods.

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Section: Current Industry Observationmentioning

confidence: 99%

One Stage Forward or Two Stages Back, What are We Treating? Identification of Internal Casing Erosion During Hydraulic Fracturing - A Montney Case Study Using Ultrasonic and Fiber-Optic Diagnostics

White

Friehauf

Cramer

et al. 2020

Day 2 Tue, October 27, 2020

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show abstract

“…Although PnP has been considered to be able to provide high operational and cost efficiency, the field cases revealed that even distribution of fracturing fluid and proppant across individual cluster is really challenging. 5,6 The behind-the-scenes reason is that the fracturing fluid follows the path of least resistance to penetrate into and break down formations. For tightly spaced multiple clusters, the stress shadow may also make the situation more severe.…”

Section: Introductionmentioning

confidence: 99%

“…PnP completions use closely spaced multiple perforation clusters to generate and place multiple fractures during each fracture stage. Although PnP has been considered to be able to provide high operational and cost efficiency, the field cases revealed that even distribution of fracturing fluid and proppant across individual cluster is really challenging. , The behind-the-scenes reason is that the fracturing fluid follows the path of least resistance to penetrate into and break down formations. For tightly spaced multiple clusters, the stress shadow may also make the situation more severe. , To overcome these challenging issues, chemical diverters have been deployed in the petroleum industry as fluid diverting agents, which is also named as temporary plugging fracturing technology.…”

Section: Introductionmentioning

confidence: 99%

Modeling Temporary Plugging Agent Transport in the Wellbore and Fracture with a Coupled Computational Fluid Dynamics–Discrete Element Method Approach

et al. 2021

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As the consumption of oil and gas resources is increasing, secondary exploitation in old wells and unconventional oil and gas exploitation methods are becoming increasingly important. As a result of complex reservoir environments and the reservoir properties, such as ultralow porosity and permeability, hydraulic fracturing is an important means to achieve effective recovery. Temporary plugging fracturing is currently an efficient fracturing technology and is suitable for refracturing of old wells and multi-stage fracturing in unconventional reservoirs, which is conducive to constructing complex fracture networks and increasing production. Recently, in the field of temporary plugging fracturing, how to design the operation parameters of temporary plugging fracturing still remains ambiguous and empirical. In this paper, a numerical simulation study of the liquid–solid two-phase flow of the temporary plugging agents and the fracturing fluid was conducted using two physical models: a wellbore flow model and a wellbore–fracture temporary plugging model. The transport processes of the temporary plugging agents along with fracturing fluid in a vertical wellbore, in a horizontal wellbore, and at a fracture position were simulated. Simulations that coupled computational fluid dynamics and the discrete element method were used in the simulation process. The effects of the temporary plugging agent concentration, particle size, particle size ratio, fracturing fluid rate, and fracturing fluid viscosity on the migration process of the temporary plugging agent were investigated. The simulation results show that a higher concentration and viscosity of a temporary plugging agent help to sustain the flow stability in the vertical wellbore, while the viscosity and flow rate of the fracturing fluid have an impact on whether sedimentation of the temporary plugging agent occurred in the horizontal wellbore. In addition, the particle size ratio and concentration of the temporary plugging agent are the key factors for a successful bridging and plugging. For a specific field application in Longmaxi Formation, Sichuan Province, the operation parameters of temporary plugging fracturing have been designed and achieved a successful refracturing treatment.

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Machine learning-based fracture-hit detection algorithm using LFDAS signal

et al. 2019

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Low-frequency distributed acoustic sensing (LFDAS) signal has been used to detect fracture hits at offset monitor wells during hydraulic fracturing operations. Typically, fracture hits are manually identified, which can be subjective and inefficient. We implemented machine learning-based models using supervised learning techniques in order to identify fracture zones, which demonstrate a high probability of fracture hits automatically. Several features are designed and calculated from LFDAS data to highlight fracture-hit characterizations. A simple neural network model is trained to fit the manually picked fracture hits. The fracture-hit probability, as predicted by the model, agrees well with the manual picks in training, validation, and test data sets. The algorithm was used in a case study of an unconventional reservoir. The results indicate that smaller cluster spacing design creates denser fractures.

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Fiber-Optic Monitoring: Stimulation Results From Unconventional Reservoirs

Cited by 19 publications

References 13 publications

One Stage Forward or Two Stages Back, What are We Treating? Identification of Internal Casing Erosion During Hydraulic Fracturing - A Montney Case Study Using Ultrasonic and Fiber-Optic Diagnostics

One Stage Forward or Two Stages Back, What are We Treating? Identification of Internal Casing Erosion During Hydraulic Fracturing - A Montney Case Study Using Ultrasonic and Fiber-Optic Diagnostics

Modeling Temporary Plugging Agent Transport in the Wellbore and Fracture with a Coupled Computational Fluid Dynamics–Discrete Element Method Approach

Machine learning-based fracture-hit detection algorithm using LFDAS signal

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