PSI - Issue 22

Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000 – 000

www.elsevier.com/locate/procedia

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 22 (2019) 33–42

© 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the First International Symposium on Risk and Safety of Complex Structures and Components organizers © 2019 The Authors. Published by Elsevier B.V.This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the First International Symposium on Risk and Safety of Complex Structures and Components organizers concentration of p rf rated holes. The experimental and theoretical study shows th t: th stress concentration efficients around perforated hole were about 1.3 and the remaining strength will b d cr ased more when both stres conc ntration and stress intensity fac ors are took into consideration. Taking th mostly us d p rforating parameter as an example, he collapse strength a perforated casing with 16 perforations/m and 90°helix may be decreased 12%. Based on the results of the experimental and theoretical study of this paper, the working parameters were decided and guidelines were developed to ensure the safety of perforated casing and wel int grit . © 2019 The Authors. Publ shed by Elsev er B.V.This is an open access article u er th CC BY-NC-ND li ens (http://cr a ivecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the First International Symposium on Risk and Safety of Complex Structures and Components organizers Abstract Due to the perforated holes on casings after perforating, the strength of perforated casings will be decreased and the well integrity will be influenced during sequential well services. To get the remaining strength of perforated casings, experimental and theoretical study were completed. The samples of perforated casings were obtained from conventional oil field casings perforated in simulation well according to oilfield perforating practice, and the stress concentration coefficients around perforated holes were measured and confirmed by experiments and finite element analysis. Taking the perforated holes as semi-elliptical surface cracks on casings, the formula for calculating stress intensity factors and revised coefficients of perforated holes were derived. Then, both strength safety and stress intensity factors were applied to evaluate the safety of perforated casings. So, the safety analysis method for perforated casings is improved and more considerate. Considering the similarity of compressed rod and pipe, the formula for calculating the remaining collapse strength of thin walled casings were developed, taking account the stress concentration of perforated holes. The experimental and theoretical study shows that: the stress concentration coefficients around perforated holes were about 1.3 and the remaining strength will be decreased more when both stress concentration and stress intensity factors are took into consideration. Taking the mostly used perforating parameter as an example, the collapse strength of a perforated casing with 16 perforations/m and 90°helix may be decreased 12%. Based on the results of the experimental and theoretical study of this paper, the working parameters were decided and guidelines were developed to ensure the safety of perforated casing and well integrity. Abstract Due to the perforat d h les on casings after p rf rating, th strength of p rfor ted casings will be decreased and the well integrity will be influenced during sequential well se v ces. To g t the remaining strength of perforated casings, experimental and th oretic l stu y were completed. The sa ple of perforat d casings were obt ined from conventional oil field casings perfo ated in simulation well according to oilfield perfora ing practice, and the stress concentrat on coef ici nts around perfo ated holes were measured and confirmed by xperimen s and finite l ment analysis. Taking the p rforated h les as semi-elliptical sur ace cr ck on casings, th mula for calculating stress intensity factors nd revi ed coefficients of perforated hol s were derived. Then, both strength safety and stress intensity factors were applied to evaluate the safety of perforated casings. So, af ty analysis meth d for perforated casings is improved and more considerate. C nsidering the similarity of compressed rod and pipe, the formula for calcul ting the remaining collapse of thin wall d casings er developed, taki g accou t the Keywords: Perforated casing; Mechanical characteristics;Experimental study; Theoritical study First International Symposium on Risk and Safety of Complex Structures and Components Experimental and Theoretical Study on the Mechanical Characteristics of Perforated Casings First International Symposium on Risk and Safety of Complex Structures and Components Experiment l nd Theoretical Study on the Mechanical Characteristics of Perforated Casings Yihua Dou a *,Yinping Cao a , Mingfei Li a ,Yafei Zhang a a Mechanical Engineering College, Xi’an Shiyou University, Xi’an, Shaan xi, 710065, China Yihua Dou a *,Yinping Cao a , Mingfei Li a ,Yafei Zhang a a Mechanical Engineering College, Xi’an Shiyou University, Xi’an, Shaan xi, 710065, China

* Corresponding author. Tel.: +86-139-0918-3925; fax: +86-029-8838126. E-mail address: yhdou@vip.sina.com Keywords: Perforated casing; Mechanical characteristics;Experimental study; Theoritical study

* Corresponding author. Tel.: +86-139-0918-3925; fax: +86-029-8838126. E-mail address: yhdou@vip.sina.com

2452-3216 © 2019 The Authors. Published by Elsevier B.V.This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review statement: Peer-review under responsibility of the First International Symposium on Risk and Safety of Complex Structures and Components organizers 2452-3216 © 2019 The Authors. Published by Elsevier B.V.This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review statement: Peer-review under responsibility of the First International Symposium on Risk and Safety of Complex Structures and Components organizers

2452-3216 © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the First International Symposium on Risk and Safety of Complex Structures and Components organizers 10.1016/j.prostr.2020.01.005