Wellbore Stability: A New Conceptual Approach Based on Energy

Santos, Hélio; Diek, A.; Roegiers, J.-C.

doi:10.2118/49264-ms

Cited by 10 publications

(6 citation statements)

References 5 publications

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“…annular space, Santos et al 12 estimates the amount of kinetic energy transferred to the rock as being approximately 2.7 kJ. It shall be presented here another approach to quantify this same energy transference.…”

Section: Stability Analysis Through Energymentioning

confidence: 93%

Consequences and Relevance of Drillstring Vibration on Wellbore Stability

Helio

Placido

Claudio

1999

Proceedings of SPE/IADC Drilling Conference

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractHistorically, wellbore instability problems have been mainly attributed to the physico-chemical interaction between the rock and the drilling fluid, especially when this is a waterbased fluid (WBM). However, recent studies have shown that these chemical effects may be irrelevant in comparison with other energetic events which are present during the drilling operation of a well. Excessive drillstring vibration has been identified as such an event that can cause a great amount of damage to the wellbore. Although some studies present clear indications that the reduction of drillstring vibration has led, in many occasions, to an improvement on instability problems, still today this item only deserves attention from equipment divisions, aiming at reducing drillstring fatigue problems.The main objective of this paper is to show the clear existing relation between excessive drillstring vibrations and serious well instability problems. It is shown, in energetic terms, that drillstring vibration, when having enough lateral amplitude to hit the wall, is responsible for irreparable damage to the borehole. Simple ways of quantifying vibration effects in terms of energy are presented. The paper also presents field measurement data, obtained with surface vibration sensors, which clearly allow identification and correlation between vibration problems and wellbore instability, through the comparison of these vibration records with caliper logs.

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Section: Stability Analysis Through Energymentioning

confidence: 93%

Consequences and Relevance of Drillstring Vibration on Wellbore Stability

Helio

Placido

Claudio

1999

Proceedings of SPE/IADC Drilling Conference

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“…This validated fact has been discussed widely in the literature, along with all associated drilling problems (Santarelli and Carminati 1995;Civan 1999). To minimize the negative effect that shale swelling produces on drilling performance, two major chemical solutions were defined in the past: OBM (Santarelli 1992 et al), or redefined-chemistry WBM (Santos et al 1998). The drilling efficiency while drilling across reactive, time-dependent shale is still questionable, however.…”

Section: Operational Challengementioning

confidence: 99%

Casing While Drilling (CwD): A New Approach To Drilling Fiqa Formation in the Sultanate of Oman—A Success Story

Sánchez¹,

Houqani²,

Turki

et al. 2012

SPE Drilling &Amp; Completion

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Highly reactive Fiqa shale used to compel well engineers in the Sultanate of Oman to plan drilling phase of surface and intermediate sections primarily based on time exposure to aqueous drilling fluid water-based mud (WBM). The new approach of drilling the time-dependent Fiqa formation using casing-while-drilling (CwD) allows well engineers to plan prospective top/intermediate wellbore sections differently by enhancing the overall drilling performance. This reduces the risk of setting casing strings at unplanned depths, getting pipe stuck, or reaming continuously when drilling with conventional drillstring. The technical feasibility study, risk assessment, planning, execution, and the lessons learned during the process of drilling two top-section pilot projects are described in this document. The CwD team compares the drilling performance of several offset wells and suggests actions to improve the CwD technology in Oman.Two 17 1 =2and 22-in. surface sections were drilled successfully with large-diameter casing strings and reached 754-and 894-m measured depths, respectively. The implementation of the CwD concept reduced the overall drill/case phase time up to 40%, in comparison with the average using conventional drilling in those fields. Exposure time of Fiqa to aqueous environment was reduced by eliminating conditioning trips and nonproductive-time (NPT) associated with wellbore instability. Drilling both sections with non-retrievable 17 1 = 2 Â13 3 = 8 -in. and 22Â18 5 = 8 -in. CwD systems did not require modification of well design or rig. The optimization of this technology will support its implementation as the conventional drilling approach in some fields in Oman.

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“…Two major chemical solutions were defined in the past to manage this drilling problem: oil-based mud (8) or redefine chemical composition of water-based muds. Although some solutions work on wellbore stability, it is wellknown that water-based mud with special chemistry has been highly successful in clayey formations (9) . However, the drilling efficiency while drilling across reactive, time-depended shales is still questionable.…”

Section: Operational Challengementioning

confidence: 99%

Casing While Drilling (CwD); A New Approach Drilling FIQA Formation in the Sultanate of Oman. A Success Story

Sanchez¹,

Turki

Nabhani³

et al. 2010

Abu Dhabi International Petroleum Exhibition and Conference

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The highly reactive FIQA shale used to compel well engineers in The Sultanate of Oman to plan the drilling phase of surface and intermediate sections based on time exposure to aqueous drilling fluid system (WBM). The new approach of drilling the timedependent FIQA shale formation using Casing-while-Drilling (CwD) allows well engineers to plan prospect top/intermediate wellbore sections differently by enhancing the drilling performance and reducing the risk of setting casing strings shallower, external corrosion due to aquifers, and getting stuck or reaming continuosly while drilling conventionally. The technical feasibility study, planning, risk assessment, execution, as well as the lessons learned during the process of drilling top sections are described in this document. The CwD team compares the drilling performance of several offset wells and suggest actions to improve the CwD technology in Oman.Two surface sections were drilled successfully with large OD casing strings. Both surface sections 17½" and 22" reached 750m and 894m measured depth, respectively, reducing drilling phase by 40-45% in comparison with the average in the field. The exposure time of FIQA to aqueous environment was reduced considerably eliminating conditioning trips and non-productive-time (NPT) associated with wellbore instability. The volume of returns as cementing increased from 20% -with conventional drillstring -to 92-98% of pumped excess volume. CwD will allow drilling teams to slim down top holes by drilling/casing much deeper sections within less time preventing FIQA from collapsing and avoiding potential applications of Oil Based Mud (OBM). This new technology may also allow the optimization of existing rigs reducing cost and size of rig prints, as well as minimize HSE risk while handling large-OD casing and extremely heavy DC's.Simulation of the drilling phase using torque/drag and BHA-analysis software were run. The drillable PDC bit performance is compared to bit-records from offset wells recently drilled with conventional BHA's. The effect of CwD on resulting uniform cement sheath (related to the "smear effect") and the reduced size of cuttings at surface which positively aid on preventing flowline plugging as an unplanned event will be described.It is important to highlight that Nonretrievable 17½"x13⅜" and 22"x18⅝" CwD with drillable bit and the casing drive mechanism, did not require any rig modification. The optimization of the process as well as the familiarization of drilling teams with the main components of the CwD system, will lead to a long, demanding scope for its implementation in several fields in Oman.

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Wellbore Stability: A New Conceptual Approach Based on Energy

Cited by 10 publications

References 5 publications

Consequences and Relevance of Drillstring Vibration on Wellbore Stability

Consequences and Relevance of Drillstring Vibration on Wellbore Stability

Casing While Drilling (CwD): A New Approach To Drilling Fiqa Formation in the Sultanate of Oman—A Success Story

Casing While Drilling (CwD); A New Approach Drilling FIQA Formation in the Sultanate of Oman. A Success Story

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