Successful mitigation of time-dependent shale instability in Khafji field through drilling fluid design optimization

Chee Phuat Tan, Marwan Ahmad Qadmani, Magdalena Povstyanova, Mohammed Ahmed Mohiuddin, Mohd. Helmi Abd. Rahim

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)

Abstract

Al-Khafji Joint Operations is developing the offshore Khafji Field in the X-Neutral Zone by drilling horizontal wells. These wells encounter shale formations namely Ahmadi Shale and Wara Shale before reaching the pay zones, and Intermediate Shale between KB-1 and KB-2 Sands. While drilling these shale formations, severe timedependent wellbore instability problems due to shale sloughing were experienced. These problems have led to several stuck pipes and sidetracks. A drilling fluid optimization study was conducted on seven offset wells in the field in order to evaluate the potential time-dependent wellbore stability mechanism(s) in Ahmadi Shale, Wara Shale and Intermediate Shale, to define appropriate mud type, salt type and concentration, and to develop solution and strategy to mitigate and/or manage the wellbore instability problems. End of Well reports of selected offset wells were reviewed, and numerous time-dependent wellbore instabilityrelated drilling events in Ahmadi Shale, Wara Shale and Intermediate Shale were identified. Both mud pressure penetration and chemical potential mechanisms were considered in the back-analysis of time-dependent wellbore instability in the shales. The analysis showed that the instability was attributed to insufficient salinity in the drilling fluid which resulted in pore pressure increase due to the mud pressure penetration mechanism being not counteracted by the chemical potential mechanism. As a consequence, the pore pressure increased near the wellbore wall which reduced the effective mud support and led to unstable wellbore condition. Based on the drilling fluid optimization study together with input from mechanical wellbore stability analysis, recommendations on optimum drilling fluid design were made for drilling Ahmadi Shale and Wara Shale which were successfully applied in a planned horizontal well in the field.

Original languageEnglish
Title of host publicationSociety of Petroleum Engineers - SPE Saudi Arabia Section Technical Symposium 2009
PublisherSociety of Petroleum Engineers
ISBN (Print)9781613990216
Publication statusPublished - 1 Jan 2009
Externally publishedYes
EventSPE Saudi Arabia Section Technical Symposium 2009 - Al-Khobar, Saudi Arabia
Duration: 9 May 200911 May 2009

Other

OtherSPE Saudi Arabia Section Technical Symposium 2009
CountrySaudi Arabia
CityAl-Khobar
Period9/5/0911/5/09

Fingerprint

Drilling fluids
drilling fluid
Shale
shale
mitigation
Drilling
well
mud
Chemical potential
Horizontal wells
Pore pressure
drilling
Design optimization
pore pressure
penetration
horizontal drilling
back analysis
Mechanical stability
stability analysis
Sand

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Fuel Technology
  • Geochemistry and Petrology

Cite this

Tan, C. P., Qadmani, M. A., Povstyanova, M., Mohiuddin, M. A., & Abd. Rahim, M. H. (2009). Successful mitigation of time-dependent shale instability in Khafji field through drilling fluid design optimization. In Society of Petroleum Engineers - SPE Saudi Arabia Section Technical Symposium 2009 Society of Petroleum Engineers.

Successful mitigation of time-dependent shale instability in Khafji field through drilling fluid design optimization. / Tan, Chee Phuat; Qadmani, Marwan Ahmad; Povstyanova, Magdalena; Mohiuddin, Mohammed Ahmed; Abd. Rahim, Mohd. Helmi.

Society of Petroleum Engineers - SPE Saudi Arabia Section Technical Symposium 2009. Society of Petroleum Engineers, 2009.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Tan, CP, Qadmani, MA, Povstyanova, M, Mohiuddin, MA & Abd. Rahim, MH 2009, Successful mitigation of time-dependent shale instability in Khafji field through drilling fluid design optimization. in Society of Petroleum Engineers - SPE Saudi Arabia Section Technical Symposium 2009. Society of Petroleum Engineers, SPE Saudi Arabia Section Technical Symposium 2009, Al-Khobar, Saudi Arabia, 9/5/09.
Tan CP, Qadmani MA, Povstyanova M, Mohiuddin MA, Abd. Rahim MH. Successful mitigation of time-dependent shale instability in Khafji field through drilling fluid design optimization. In Society of Petroleum Engineers - SPE Saudi Arabia Section Technical Symposium 2009. Society of Petroleum Engineers. 2009
Tan, Chee Phuat ; Qadmani, Marwan Ahmad ; Povstyanova, Magdalena ; Mohiuddin, Mohammed Ahmed ; Abd. Rahim, Mohd. Helmi. / Successful mitigation of time-dependent shale instability in Khafji field through drilling fluid design optimization. Society of Petroleum Engineers - SPE Saudi Arabia Section Technical Symposium 2009. Society of Petroleum Engineers, 2009.
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