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Completion Installation and Operations
ABSTRACT The lack of knowledge of lateral heterogeneity in unconventional reservoirs commonly has negative impacts on drilling, completion efficiency, and production. However, current methods, such as well logging and seismic surveying, are limited in their ability to characterize unconventional reservoirs. We develop an alternative geophysical approach that uses distributed acoustic sensing (DAS) and perforation shots to characterize unconventional reservoirs. In our field data set, DAS-recorded perforation shots show strong P-wave signals. The recorded P-wave waveforms from the study area exhibit dispersive behavior, which can be clearly identified after signal processing. The spatial variations in phase velocity along the horizontal wellbore can be reliably measured by averaging the measurements from multiple closely situated perforation shots. We observe a low phase-velocity zone along the study well, which is spatially consistent with the well logs and root mean square amplitude extracted from the 3D seismic volume. The observed dispersive behavior of P waves is validated through numerical modeling. By comparing the results from the proposed method with those from modeling results and other measurements, we conclude that the proposed method results in a reasonable radius of investigation for unconventional reservoir characterization. The method also has the potential to infer hydraulic fracturing effectiveness by comparing the phase-velocity difference before and after stimulation. The data acquisition of the proposed workflow can be combined with perforation shot operations, which provides a cost-effective and suitable approach to investigating lateral heterogeneity in unconventional reservoirs.
- Geophysics > Seismic Surveying > Seismic Processing (1.00)
- Geophysics > Seismic Surveying > Seismic Modeling > Velocity Modeling (1.00)
- Geophysics > Seismic Surveying > Passive Seismic Surveying > Microseismic Surveying (1.00)
- Geophysics > Seismic Surveying > Borehole Seismic Surveying > Vertical Seismic Profile (VSP) (0.68)
This topic presents the basic elements of a coiled tubing well intervention and outlines the steps involved in pre-job planning, job execution, and post-job activities from a field engineering/operations standpoint. The general surface and subsurface equipment used in coiled tubing operations are discussed, as well as downhole tools provided by the major service companies and used by coiled tubing operators. In addition, this topic describes general operating procedures for carrying out coiled tubing operations, with an emphasis on HSE considerations.
Provides an overview of shaped charge operating principles, charge conveyance methods and charge carrier systems. Outlines commonly used perforating techniques and their areas of application. Describes basic design and operating considerations related to overbalanced vs. underbalanced perforating, detonation safeguards, depth control and perforating fluids. Examines the effects of key reservoir characteristics and well parameters on perforation performance and reviews the basic types of perforator tests recommended by the API RP 19B standard. Describes the major equipment components, job planning considerations and operating procedures involved in wireline perforating, tubing conveyed perforating, coiled tubing and pump-down perforating.
This topic presents the basic elements of a slickline well intervention and outlines the steps involved in pre-job planning, job execution, and post-job activities from a field engineering/operations standpoint. The general surface and subsurface equipment used in slickline operations are discussed as well as downhole slickline tools provided by the major service companies and used by slickline operators. In addition, this topic describes general operating procedures for carrying out slickline operations, with an emphasis on HSE considerations.
Select the appropriate tubing and accessories for completing wells in keeping with the production method required for the reservoir, and to facilitate future workover, servicing and stimulation work.Upon completion of this module, the participant should be able to select the proper sizes and grades of tubulars to maintain the integrity of the wellbore and handle anticipated production, as well as select the downhole casing and tubing accessories needed to optimize production and future well work.
Unconventional Reservoirs: Contact Area and Fracture Network Resulting from Perforations in Shale. A Comparative Study of Different Shale Targets and Shaped Charge Designs Optimized for Hydraulic Fracturing
Loehken, J. (DynaEnergetics Europe GmbH, Troisdorf, Germany) | McNelis, L. (DynaEnergetics Europe GmbH, Troisdorf, Germany) | Yosefnejad, D. (DynaEnergetics Europe GmbH, Troisdorf, Germany) | Will, D. (DynaEnergetics Europe GmbH, Troisdorf, Germany)
Abstract After decades of a continuous improvement of the plug and perf technology for horizontal wells and especially the shaped charges employed, operators nowadays have the choice between a variety of shaped charge designs. As a guidance to choose the optimal charge, this snapshot examines the influence of shale rock type and shaped charge design on the tunnel created in the reservoir rock during perforation. Tests were conducted in an API Section II Test environment, simulating in-situ downhole conditions. Specifically, the investigation focused on the characteristics of the contact surface and the induced fracture network resulting from different perforation charges, each with its own distinctive tunnel geometry. Three different shaped charge designs were tested on various shale targets. This included equal entrance hole charges, maximum formation contact, and oriented perforation tailored charges. To assess the impact of the formation rock on the results, test shots were made on Marcellus, Mancos, and Lotharheiler, which is similar to the Haynesville or Eagle Ford, shale cores. The analysis included CT scans to identify tip fractures and to examine the shape of the tunnel as well as conventional core analysis. Additionally, newly formed fractures within the rock and on the surface of the perforation tunnel were identified. The test results indicate that both the charge type and the rock type significantly influence the tunnel geometry and fracture network. Although all charges created roughly the same entrance hole diameter in the casing, variations in tunnel length and contact surface as well as in the newly created fractures were observed. Notably, the shape of the tunnel deviated strongly from the theoretical assumed cylindrical or conical tunnel. Doglegs, as well as cavities were detected at many tunnel tips, which change the overall stress field at the tunnel wall. To determine which rock parameters are relevant, the cores underwent analysis in an external laboratory to assess their petrophysical properties for further correlation analysis. From a practical perspective shale rock proved to be a challenging target rock due to its high anisotropy and significant differences in rock strength between targets of the same formation. Additionally, the target cores were prone to cracking during the rock preparation process. Therefore, this study should be considered as a snapshot and conclusions drawn from this set of tests should be approached cautiously and account for these circumstances. Our study provides insights into the dependency of the perforation result on the type of shale and charge design. Depending on the combination of the perforation technique and the characteristics of the rock formation, distinct fracture networks and tip deviations are formed. This improved understanding will help to identify the best perforation strategy tailored to the specific reservoir rock's unique properties.
- North America > United States > Texas (1.00)
- Europe (1.00)
- North America > United States > West Virginia > Appalachian Basin > Marcellus Shale Formation (0.99)
- North America > United States > Virginia > Appalachian Basin > Marcellus Shale Formation (0.99)
- North America > United States > Texas > West Gulf Coast Tertiary Basin > Eagle Ford Shale Formation (0.99)
- (18 more...)
Abstract This paper documents the results of diagnostic tests in a well that was equipped with measuring devices for analyzing pressure and acoustic behavior during multistage fracturing treatments. This well was also surveyed by an ultrasonic device for measuring the entry hole sizes of treated and untreated perforations. Well and treatment design parameters selected for scrutiny included cluster perforation density and the circumferential phase angle of entry holes with respect to elevation. Perforation erosional analysis was performed on each frac stage of the diagnostic wells by comparing perforation sizes of treated perforations with intentionally untreated perforations to estimate the eroded area for each perforation, then applying a two-component erosion model to allocate proppant among all the clusters for that frac stage. The allocated proppant was then used to compute treatment uniformity and compared with allocation and uniformity values determined by the DAS provider. This unique dataset was used to perform five categories of analyses: pipe/casing friction pressure, step down testing, perforation entry hole erosion, treating pressure, and inter-cluster proppant allocation and uniformity. Determination of perforation entry-hole erosion parameters are shown to have diagnostic value in assessing treatment confinement and identifying deviations from standard erosion theory. The impact of variable and uncertain initial (untreated) entry hole sizes is shown to adversely impact the accuracy of both DAS and erosion-based proppant allocation routines. Evidence is provided quantifying the negative effect of proppant separating from the fluid stream due to inertia on the accuracy of treatment distribution provided by DAS interpretation.