Utilizing Innovative Flexible Sealant Technology in Rigless Plug and Abandonment

Barclay, Ian; Johnson, Carl R.; Staal, Timo W.; Choudhary, Sudhanshu; Al-Hamandani, Abdulhameed

doi:10.2118/89622-ms

Cited by 8 publications

(1 citation statement)

References 9 publications

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“…The system selected was a flexible cement system, as described previously (Brufatto et al 2003;Le Roy-Delage et al 2000). These systems were used for successful abandonments in less severe environments (Barclay et al 2004). They achieved the following:…”

Section: Introductionmentioning

confidence: 99%

Laboratory and Field Validation of a Sealant System for Critical Plug-and-Abandon Situations

Nagelhout¹,

Bosma²,

Mul³

et al. 2010

SPE Drilling &Amp; Completion

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This paper presents case histories and discusses the laboratory validation of a sealant system for plug-and-abandon (P&A) operations in critical gas wells close to habitations. To ensure long-term isolation both inside and outside the original casing, the plan was to mill out the casing and cement and to place the plug from rock face to rock face. The milled-out section was planned so that in the worst-case scenario, the differential gas pressure would have to be supported by 25 m of cement plug, even though a greater height of cement would be placed inside the original casing above the milled-out section.Two cement systems were designated as candidates for the plugging operation with slurry properties suitable for the application. The gas-sealing ability of the selected systems was validated with both small-scale and large-scale tests. One system, exhibiting both high flexibility and expansion, met the stringent specifications and did not leak until a differential pressure of more than four times the specification was applied. The paper will discuss the parameters of the selected system, thus providing guidelines for system selection for critical plugging operations. A detailed case history of one well (two plugs) is given along with the results from four other wells.

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Section: Introductionmentioning

confidence: 99%

Laboratory and Field Validation of a Sealant System for Critical Plug-and-Abandon Situations

Nagelhout¹,

Bosma²,

Mul³

et al. 2010

SPE Drilling &Amp; Completion

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Potential utilization of class C fly ash-based geopolymer in oil well cementing operations

Khalifeh

Saasen

Vrålstad

et al. 2014

Cement and Concrete Composites

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Plugging Wells with Hydrated Bentonite, Part 2: Bentonite Bars

Towler

Victorov²,

Zamfir³

et al. 2008

SPE Annual Technical Conference and Exhibition

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Data for the kinetics of the swelling of bentonite bars are shown and measurements for the friction factor between the hydrated bars and steel and plastic pipe are given. The results are compared with a previously derived equation for pressure containment. These results demonstrate that the bars produce a hydrated bentonite that has similar or better pressure containment than other bentonite solutions. Bentonite has long been used for the plugging of water wells and these bars have been produced for use in the plugging and abandonment of oil and gas wells. Introduction In a previous paper (Towler and Ehlers, 1997) the process for using bentonite (sodium montmorillinite) for plugging wells was described and an equation was derived for calculating the pressure that could be contained by a bentonite plug. The friction factor in this equation was determined from lab measurements. The process for plugging wells with bentonite is already widely used for shallow water wells in a variety of forms (James, 1996 and Wheaton et al. 1994) and has been gaining acceptance for plugging oil and gas wells (Clark and Salsbury, 2003, Idialu et al., 2004). The potential is that plugging wells with bentonite is much cheaper and more reliable than concrete plugs (Clark and Salsbury, 2003). It is claimed to be more reliable because concrete can fail to seal or later crack due to ground movement or tectonic activity. Hydrated bentonite, on the other hand, is deformable and hence self sealing in such circumstances. However one of the problems with the process is getting the bentonite to the bottom of the hole before it sets up. Simply pouring bentonite granules into the well tends to result in bentonite swelling and bridging soon after it hits the water column. This holds the bentonite at a site above where it needs to be. A solution to this problem is to compress the bentonite into bullet shaped bars using a suitable binder. This retards the hydration kinetics and allows the bentonite to be deposited to the correct plug location before the swelling occurs. In this paper bentonite pellets have been compressed into a bullet shape and then hydrated into a plug for sealing against steel casing. The pressure to dislodge this plug has been measured and used to determine the friction factor between the bentonite and steel. Literature review The costs to plug and abandon (P&A) a well can be substantial. Kaiser and Dodson (2008) have recently reviewed the P&A cost trends for the Gulf of Mexico and the average cost to abandon a well there has risen to $178,000 in 2007 up from $107,000 in 2002. The price would have been even higher if not for economies of scale and turn-key operations. Using day rates the cost of well abandonment has peaked at $235,000/well in 2006. The standard procedure for well abandonment has been well documented (Smith, 1993, Kelm and Faul, 1999, Calvert and Smith, 1994). In the oil and gas industry the standard procedure involves setting a cement plug across the perforations and at certain other intervals required to isolate critical zones. This has usually involved the use of a workover rig but recently coiled tubing units have become popular for reducing costs (Barclay et al., 2004, Chong et al., 2000, Tettero et al., 2004).

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Utilizing Innovative Flexible Sealant Technology in Rigless Plug and Abandonment

Cited by 8 publications

References 9 publications

Laboratory and Field Validation of a Sealant System for Critical Plug-and-Abandon Situations

Laboratory and Field Validation of a Sealant System for Critical Plug-and-Abandon Situations

Potential utilization of class C fly ash-based geopolymer in oil well cementing operations

Plugging Wells with Hydrated Bentonite, Part 2: Bentonite Bars

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