A Complete Integrated Model for Design and Real-Time Analysis of Hydraulic Fracturing Operations

Crockett, A.R.; Okusu, N.M.; Cleary, M.P.

doi:10.2523/15069-ms

Cited by 50 publications

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“…(We note that the gammas have quite different usage in Refs. 8,9, from that in Ref. 12, and that the results differ somewhat in detail; however, the results that we quote below will be sufficiently independent of the different modelling approaches to make our point.…”

supporting

confidence: 52%

“…7) simulations, then applying the resulting practical computer-based models (Refs. 8,9) to field applications, using actual data and on-site analysis (e.g. Ref.…”

mentioning

confidence: 99%

“…13), model development (beyond that in Refs. 8,9), and matching of numerous field data-sets to COnlJrnl the basic theories, are being submitted separately for publication by SPE. As well, GRI is undertaking a comprehensive fieldJest, called the Hydraulic Fracture Test Site (HFTS), which will directly test a number of the conclusions presented here --providing a level of detailed field measurement and confident analysis which has not been possible with such previous undertakings (e.g.…”

mentioning

confidence: 99%

“…including flow-rate changes Q(t) and shut-in (Q=O), led us to re-formulate the equations (Refs. 8,9) in a form which allowed real-data analysis and efficiently represented all possible scenarios; we now lmd that the resulting forms are the only rational approach for general and practical modelling of hydraulic fracturing. (We note that the gammas have quite different usage in Refs.…”

mentioning

confidence: 99%

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Experimental and Modeling Evidence for Major Changes in Hydraulic Fracturing Design and Field Procedures

Cleary

Wright

1991

SPE Gas Technology Symposium

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The paper presents some important conclusions obtained by analysis of data from many hydraulic fracturing treatments monitored over the past five years. These conclusions involve some major changes from conventional concepts about hydraulic fracturing, many of which have been based on inadequate models of the process and a commensurate lack of adequate data or motivation to check those models. Recommendations are, therefore, also made about simple, low-cost procedures for adequate data collection, such as the use of flow-rate changes and/or multiple injection/shut-in cycles for stringent model evaluation. Our conclusions from such careful analysis include: shorter, wider fractures; relative insensitivity of fracture width to frac-fluid rheology; dangerously fast convection vs. settlement of proppant in imperfectly-contained fractures; and a potential role of natural fractures in explaining many phenomena formerly regarded as evidence for long contained fractures. Although serendipity may sometimes compensate for poor job design, we recommend that many existing approaches to fracture design and execution be re-considered and that more credible efforts at treatment optimization be achieved by more careful (on-site) analysis of properly monitored and more flexible field execution schedules. lIItroductionThe theory and practice of hydraulic fracturing abound ",":ith concepts, analysis techniques and procedures for creat~g "optimum fracture geometries" in representative reservoIrS.References and illustrations at end of paper. 131These ideas have evolved somewhat over the past twenty years, as may be seen, for instance, by comparing Ref. I and Refs. 2, 3: the most obvious, but still hard-won, recognition has been that fractures are typically not well-contained in the pay-zones of the target formations. However, many other misconceptions and inadequate models or procedures still pervade the industry -despite large amounts of data which, directly or indirectly, refute those approaches. This situation is still possible because adequate data-sets are not often collected and are rarely analyzed properly, if at all; and unsatisfactory explanations are often found when anomalies are noted (e.g. Ref. 4). Indeed, clearly questionable models are still purveyed (e.g. Refs. 2,3) as adequate representations of the physical process: in particular, they do not often come close to matching the actual observed pressures, even in well-defmed job situations. Results vary from vague (e.g. Ref. 5) to demonstrably erroneous recommendations for optimum job design. One of the authors (Geary) has been working on this problem for over twelve years, fIrSt conducting laboratory (Ref. 6) and computer (Ref. 7) simulations, then applying the resulting practical computer-based models (Refs. 8,9) to field applications, using actual data and on-site analysis (e.g. Ref. 10). Some of our original concepts (e.g. the role of rheology) have changed quite dramatically (e.g. from those presented in Ref. 11), but others (such as the roles of stress, modulus an...

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supporting

confidence: 52%

“…7) simulations, then applying the resulting practical computer-based models (Refs. 8,9) to field applications, using actual data and on-site analysis (e.g. Ref.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Experimental and Modeling Evidence for Major Changes in Hydraulic Fracturing Design and Field Procedures

Cleary

Wright

1991

SPE Gas Technology Symposium

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“…Advances in technology have yielded such tools as pseudo-3D design programs, 3,4 real-time job analyses, 3,4 and methods for improving quality control for fracturing fluids. 5 These measures enable engineers to achieve packed fractures through the proper design of treatments with tip screenouts.…”

Section: Frac Designmentioning

confidence: 99%

Remediation of Production Loss Due to Proppant Flowback in Existing Wellbores

Nguyen

Stegent

Ingram

2006

SPE Annual Technical Conference and Exhibition

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThis paper presents the results of experimental study and field case histories of a remedial treatment technique using a lowviscosity consolidating agent placed into the propped fractures by coiled tubing (CT) or jointed pipe coupled with a pressure pulsing tool. The treatment fluids are designed to provide consolidation for previously placed proppant near the wellbore without damaging the permeability of the proppant pack. The consolidation treatment transforms the loosely packed proppant in the fractures and the formation sand close to the wellbore into cohesive, consolidated, yet highly permeable packs.Laboratory flow testing indicates that the proppant pack in a fracture model under closure stress required low-strength bonds between proppant grains to withstand high production flow rates. Field case histories are also presented to discuss treatment procedures, precautions, and recommendations for implementing the treatment process. One major advantage of this remedial treatment method is the ability to place the treatment fluid into the propped fractures, regardless of the number of perforation intervals and their lengths without mechanical isolation between the intervals. The fluid placement efficiency of this process makes remediation economically feasible, especially in wells with marginal reserves.

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Remediation of Production Loss Due to Proppant Flowback through Coiled-Tubing Intervention

Ingram

Nguyen

Hood³

2007

Production and Operations Symposium

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This presentation discusses the results of experimental and field case studies of a remedial treatment technique designed to eliminate fracture proppant production. This process uses a low-viscosity consolidating agent, which is placed into the propped fractures via coiled tubing or conventional tubing coupled with a pressure-pulsing tool. The treatment fluids are designed to provide consolidation for previously placed proppant near the wellbore without damaging the permeability of the proppant pack. The consolidation treatment transforms the loosely packed proppant in the fractures and the formation sand close to the wellbore into a cohesive, consolidated, yet highly permeable pack. Laboratory gas flow testing indicates that the proppant pack in a fracture model under closure stress required low-strength bonds between proppant grains to withstand high production flow rates. Field case histories are also presented to discuss treatment procedures, precautions, and recommendations for implementing the treatment process. One major advantage of this new remedial treatment technique is the ability to place the treatment fluid into the propped fractures, regardless of the number of perforation intervals and their lengths, without mechanical isolation between the intervals. The fluid placement efficiency of this process makes remediation economically feasible, especially in wells with marginally economic reserves. Introduction Many fracture-stimulated wells in the world today are subjected to curtailed production rates because of sustained proppant flowback problems. In fact, many wells are actually shut in because operators found them to be uneconomical to produce at subsequently lowered rates. Typically, production becomes restricted, such as by perforations being covered with produced proppant. The proppant produced during production often causes damage to downhole pumps and to surface equipment. In addition, repairing the equipment often results in costly downtime for the wells. Low production rates directly affect potential revenue for the operator. Frequent workovers required for cleanup or sand removal, including shut-in time, also factor into the revenue losses caused by proppant flowback or sand infill. However, the problem will return and the loss of revenue will continue unless a treatment can be found that will remediate the problem at its source and not simply clean up the wellbore. After an initial completion, it is often very difficult to conduct cost-effective remedial treatments to overcome proppant-production problems. Conventional remedial treatments are usually inadequate without some type of mechanical isolation technique. Conventional methods with a good chance of effective treatment are usually either too risky for well problems or too costly to consider for low-return reservoir conditions (or both). Resin materials have also been applied to treat proppant flowback. However, a key problem with using these materials has been the inability to achieve a uniform placement of the resin into propped fractures for the entire perforated interval. This problem is amplified by the presence of variable permeability, perforation debris, formation damage in the near-wellbore region, and the high viscosity of many resin materials. A system that attacks the problem at its source is a better approach to this problem. Using a system of treatment fluids placed precisely into propped fractures by coiled tubing can turn many marginal wells into excellent producers, and do so cost-effectively. The treatment chemicals introduced into the propped fracture will form a consolidated, highly permeable pack that can withstand the high drawdown associated with production. This paper discusses such a system.

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A Complete Integrated Model for Design and Real-Time Analysis of Hydraulic Fracturing Operations

Cited by 50 publications

References 0 publications

Experimental and Modeling Evidence for Major Changes in Hydraulic Fracturing Design and Field Procedures

Experimental and Modeling Evidence for Major Changes in Hydraulic Fracturing Design and Field Procedures

Remediation of Production Loss Due to Proppant Flowback in Existing Wellbores

Remediation of Production Loss Due to Proppant Flowback through Coiled-Tubing Intervention

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