The Art and Practice of Acid Placement and Diversion: History, Present State and Future

Kalfayan, Leonard; Martín, Alexis

doi:10.2118/124141-ms

Cited by 63 publications

(24 citation statements)

References 55 publications

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“…Coating the fluorspar with a wood resin material is desirable to delay the time of the breaker because the release of fluoride ions breaks the bonds between the polymer and cross-linker when it is introduced to the crosslinked polymer gel. Kalfayan and Martin (2009) stated that fluoride breaker decreases the gel viscosity and improves cleanup after the treatment is finished. The concentration of the breaker, acid, and the bottomhole temperature are the factors that affect the speed of the breaking mechanism.…”

Section: Previous Workmentioning

confidence: 99%

Evaluation of A New Liquid Breaker for Polymer-Based In-Situ Gelled Acids

et al. 2011

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A solid breaker is used to reduce the viscosity of the gel at pH range of 4-5 for in-situ gelled acids with Zr 4+ cross-linkers utilize. However, the literature survey confirmed that solid breakers caused a premature reduction in the fluid viscosity resulting in a less than desirable productivity. Therefore, an effective liquid breaker that is based on tetrafluoroboric acid was developed.This study was conducted to evaluate this new breaker system under the following conditions: breaker concentration (0-200 ppm), and acid injection rate (0.5-10 cm 3 /min).The major findings from the performed viscosity measurements and single coreflood experiments can be summarized as follows: the crosslinking of the polymer occurred at a pH value of 1.8. At a pH of less than 2, doubling the breaker concentration did not affect the viscosity of the acid. However, at a pH of greater than 2, the viscosity

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Section: Previous Workmentioning

confidence: 99%

Evaluation of A New Liquid Breaker for Polymer-Based In-Situ Gelled Acids

et al. 2011

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“…Execution of matrix stimulation treatments can be obtained via bullheading, or using CT for fluid placement at depth, or even by dual injection using both at the same time (Cohen et al 2010;Kalfayan and Martin 2009). Both techniques can utilize mechanical (e.g., bridge plugs, packers) and chemical (e.g., particulate diverters, self-diverting acids, and foams) means for diversion of the treatment fluids.…”

Section: Introductionmentioning

confidence: 99%

Advanced Understanding of Matrix Stimulation Treatments Through In-Job and Post-Job Evaluation of Real-Time Downhole Measurements with Coiled Tubing: A Case Study

Ahmed

Ramondenc

Baez

2014

SPE International Symposium and Exhibition on Formation Damage Control

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Matrix stimulation treatments executed with coiled tubing (CT) face various challenges in terms of design, execution, and evaluation. The design phase typically relies on information that is frequently poorly known (e.g., extent of damage). Treatment pumping schedules and fluid concentrations are often determined based on previous experience and accepted local practices. For the execution to be completed within a safe framework, the standard is to keep pumping pressures below the fracturing pressure. In some cases, tools like high pressure differential jetting nozzles are used to provide deeper penetration and lower breakdown pressures. The depths at which those tools are operated usually depend on a prior log interpretation. Finally, treatment evaluation is typically limited to the comparison of pre and post-stimulation wellhead pressures and rates.Over the past decade, numerical modeling has allowed the industry to address some of the design and evaluation challenges. Yet, the same question often remains: has the design been effectively executed and was the intervention successful? The answer depends on the choice of success criteria such as efficiency, safety, and economics.CT enabled with fiber optic telemetry-which consists of downhole gauges providing real-time data of pressure, temperature, gamma ray, and casing collar locator-has proven a game-changing technology with respect to treatment execution, improving both intervention efficiency and safety (Jacobsen et al. 2010). The provided measurements, along with the possibility to acquire distributed temperature surveys (DTS), have also shown to be the most effective solution for treatment evaluation to date.The case study presented here not only describes how CT with downhole sensors was used to optimize the acidizing treatment of an oil well producer and ensure its effective stimulation, but it also demonstrates how the real-time and DTS data were analyzed both during the intervention and through post-job numerical modeling, in order to refine the understanding of the well and that of its formation characteristics.

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“…Placement techniques may involve the use of bullheading, or coiled tubing, or a combination of both. Kalfayan and Martin (2009) and Cohen et al (2010) give extensive reviews of placement and diversion methods for matrix acidizing treatments, with their advantages and disadvantages. In most of those techniques, it is usually implied that one already knows where fluids need to be pumped along the wellbore, before starting the job.…”

Section: Introductionmentioning

confidence: 99%

Using Fiber-Optic-Enabled Coiled Tubing to Quantify Fluid Placement and Optimize Stimulation Effectiveness During Matrix Stimulation Treatments in Carbonate Reservoirs

Ramondenc

Baez

2013

All Days

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When performing matrix stimulation treatments, coiled tubing (CT) is a preferred placement technique due to the ability to spot fluid in front of the target zone(s). This method becomes a key solution when formation heterogeneities require a very selective fluid placement strategy.In today's industry, the most common approach is to design a treatment with volumes of stimulation and diverter fluids that are determined largely based on local practices. Often, it amounts to targeting a uniform stimulation, thus requiring a predefined amount of treatment fluid per length of total pay zone. That approach, although widely used and accepted, may not necessarily yield an optimum stimulation.We present an alternative technique that relies on the accurate quantification of fluid placement along the formation in order to define the respective volumes of stimulation and diverter fluids to be pumped. This method relies on the analysis of the distributed temperature sensing (DTS) data recorded by a fiber-optic line enclosed inside the CT and data processing through a fast interpretation algorithm to yield a zonal coverage profile. During a job, DTS data corresponding to the preflush can be used to estimate the initial placement distribution across the pay zone. This allows stimulation engineers to determine the best strategy for the subsequent well stimulation treatment, including fluid volumes and placement sequence. After every major pumping stage, a new DTS analysis assesses how the formation reacted to the treatment, improving placement strategy.This method has been used in multiple matrix stimulation treatments of injector and producer wells. The described innovative approach allows engineers to make more informed decisions between stages, optimizing fluid resources, fluid placement and, ultimately, stimulation effectiveness. It also leads to noteworthy advantages when designing new acidizing treatments, as companies can build on previous experience from similar wells and fields.

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The Art and Practice of Acid Placement and Diversion: History, Present State and Future

Cited by 63 publications

References 55 publications

Evaluation of A New Liquid Breaker for Polymer-Based In-Situ Gelled Acids

Evaluation of A New Liquid Breaker for Polymer-Based In-Situ Gelled Acids

Advanced Understanding of Matrix Stimulation Treatments Through In-Job and Post-Job Evaluation of Real-Time Downhole Measurements with Coiled Tubing: A Case Study

Using Fiber-Optic-Enabled Coiled Tubing to Quantify Fluid Placement and Optimize Stimulation Effectiveness During Matrix Stimulation Treatments in Carbonate Reservoirs

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