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Title: Optimal design of perforating completion for gas well

Abstract

The productivity characteristics of perforated gas well are investigated for the first time under real conditions considering drilling damage, perforation compacted zone and anisotropy in this paper. A non-linear finite element model for non-Darcy flow in perforated gas reservoir is built to consider the effects of twelve factors on productivity ratio (PR) of perforated gas well. The nomographs for two cases are presented in this paper. Compared with previous works, the following results are found: (1) the effects of drilling damage and perforation diameter on PR of gas well are more remarkable than that in oil well; (2) any perforation phase may be the best or the worst as to perforating gas well, which depends on anisotropy, drawdown and that whether or not perforations are beyond drilling damage zone; (3) the increase in perforation length hardly improve PR of gas well when perforations have been beyond drilling damage zone. The new method is suggested to predict or determine the turbulent flow co-efficient D{prime}, total skin S, pseudo skin St{prime}, and individual skin factors (Sp, Sd, Sdp) in perforated gas well. The minimum underbalance required to obtain a zero perforating skin is discussed as well. Some drawbacks of the equation proposedmore » by Tariq (SPE 20636) are analyzed and a new Reynold`s number criterion is established. The critical Reynold`s number for clean perforation is dependent on formation permeability. Based on this research, the principle and the program for optional design of perforating completion in gas well are highlighted. These new concepts, results and conclusions would be of importance to both gas well perforating and gas reservoir engineering.« less

Authors:
; ;
Publication Date:
OSTI Identifier:
103884
Report Number(s):
CONF-950326-
TRN: IM9541%%323
Resource Type:
Conference
Resource Relation:
Conference: Annual SPIE Asia Pacific oil and gas conference and exhibition: towards more cost effective technology and quality management in the petroleum industry, Kuala Lumpur (Malaysia), 20-22 Mar 1995; Other Information: PBD: 1995; Related Information: Is Part Of Asia Pacific oil and gas conference: Proceedings; PB: 592 p.
Country of Publication:
United States
Language:
English
Subject:
03 NATURAL GAS; NATURAL GAS WELLS; PERFORATION; FORMATION DAMAGE; FLUID FLOW; MATHEMATICAL MODELS; WELL COMPLETION; DESIGN

Citation Formats

Tang, Y., Pan, Y., and Wang, Y.. Optimal design of perforating completion for gas well. United States: N. p., 1995. Web.
Tang, Y., Pan, Y., & Wang, Y.. Optimal design of perforating completion for gas well. United States.
Tang, Y., Pan, Y., and Wang, Y.. Sun . "Optimal design of perforating completion for gas well". United States. doi:.
@article{osti_103884,
title = {Optimal design of perforating completion for gas well},
author = {Tang, Y. and Pan, Y. and Wang, Y.},
abstractNote = {The productivity characteristics of perforated gas well are investigated for the first time under real conditions considering drilling damage, perforation compacted zone and anisotropy in this paper. A non-linear finite element model for non-Darcy flow in perforated gas reservoir is built to consider the effects of twelve factors on productivity ratio (PR) of perforated gas well. The nomographs for two cases are presented in this paper. Compared with previous works, the following results are found: (1) the effects of drilling damage and perforation diameter on PR of gas well are more remarkable than that in oil well; (2) any perforation phase may be the best or the worst as to perforating gas well, which depends on anisotropy, drawdown and that whether or not perforations are beyond drilling damage zone; (3) the increase in perforation length hardly improve PR of gas well when perforations have been beyond drilling damage zone. The new method is suggested to predict or determine the turbulent flow co-efficient D{prime}, total skin S, pseudo skin St{prime}, and individual skin factors (Sp, Sd, Sdp) in perforated gas well. The minimum underbalance required to obtain a zero perforating skin is discussed as well. Some drawbacks of the equation proposed by Tariq (SPE 20636) are analyzed and a new Reynold`s number criterion is established. The critical Reynold`s number for clean perforation is dependent on formation permeability. Based on this research, the principle and the program for optional design of perforating completion in gas well are highlighted. These new concepts, results and conclusions would be of importance to both gas well perforating and gas reservoir engineering.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Oct 01 00:00:00 EDT 1995},
month = {Sun Oct 01 00:00:00 EDT 1995}
}

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  • A new concept in deep gas-well completions permits better stimulation attempts which can result in significant increases in well productivity. Use of 4-1/2 in. tubing and liner as a production string makes it possible to perforate a well with a large OD gun (offering larger holes and better penetration than a through-tubing gun) while maintaining a pressure differential into the well bore (underbalanced condition). Perforating with the pressure differential into the formation (overbalanced condition) can result in perforations plugged with foreign material and, if the foreign material is insoluble in acid, productivity impairment can result. Perforating underbalanced is desirable inmore » certain formations and improves the possibility that the perforations are open. The 4-1/2 in. tubulars make possible high rate treatments. It has been recognized that pumping rate is a significant factor in determining the distance live acid will penetrate down a vertical fracture. Deeper penetration of live acid maximizes the effective well bore radius which increases well productivity.« less
  • The productivity of a perforated gas well is strongly affected by non-Darcy or 'turbulent' flow through the compacted zone around each perforation. The turbulence coefficient depends on the permeability of this compacted zone. This permeability, a function of the perforation condition, can be used with perforation dimensions to predict gas well performance. An approach is presented for the problem of turbulent flow in perforated wells that are not gravel-packed. It can be used to analyze producing gas wells, or it can be combined with flowing well analysis to calculate the perforations needed to complete a gas well in a consolidatedmore » or competent formation. 13 refs.« less
  • Since 1983, the Deep Coal Seam Project (DCSP) and the Western Cretaceous Coal Seam Project (WCCSP) of the Gas Research institute has funded research efforts in the Piceance and San Juan basins of Colorado and New Mexico to further the knowledge of all facets of commercial coalbed natural gas reservoir development. Because of WCCSP research into openhole completion well effectiveness in the Fruitland play, and the need to complete a successful Cameo coal openhole well, the South Shale Ridge [number sign]11-15 well was deemed to be an excellent chance for technology transfer and evaluation. Because of implementation of carefully designedmore » air mist drilling and controlled openhole completion techniques, along with a sufficient magnitude of cleat permeability, it appears that the [number sign]11-15 well is commercial. The cavity was installed without major problems. The initial gas production test rate of roughly 280 MCFGPD is one of the best in South Shale Ridge. The [number sign]11-15 well case study is quite important in that it may serve to emphasize the point that the conservative attitude towards commercialization of previously untapped petroleum resources is often not correct. It is now an open question as to whether the conventional wisdom that most of the Cameo coal gas play is too tight to enable commercial production is indeed true, or if by analogy with Fruitland openhole wells, Cameo coal wells that have been hydraulic fracture stimulated are commonly very poorly connected to the cleat permeability of the reservoir. There is no significant reason to believe that the South Shale Ridge area is geologically unique, and thus there is a distinct possibility that more widespread Cameo coal production than has been previously recorded can be achieved.« less
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