Transition Time of Cement Slurries, Definitions and Misconceptions, Related to 
Annular Fluid Migration

Rogers, Murray; Dillenbeck, Robert; Eid, Ramy

doi:10.2523/90829-ms

Cited by 20 publications

(9 citation statements)

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“…The results also demonstrate that accomplishment of the above three main slurry characteristics to resist fluid flow invasion will ensure a right-angle set behavior by default. As previously reported, 12 designing cement slurries primarily for their right-angle set behavior may not guarantee resistance to fluid migration through cement slurries.…”

Section: A Cement Slurry May Have a Right-angled Setmentioning

confidence: 82%

“…Creating a cement sheath that provides proper zonal isolation under any circumstance should be a primary objective [1][2][3][4][5][6][7][8][9][10][11][12] in every well construction project to (1) protect fresh water from contamination, (2) provide effective interzonal isolation, and (3) provide mechanical support to the casing string. All these objectives will facilitate the production of oil and gas safely and economically over the well's lifetime.…”

Section: Introductionmentioning

confidence: 99%

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Designing Cement Slurries for Preventing Formation Fluid Influx After Placement

Santra

Reddy

Antia

2007

Proceedings of International Symposium on Oilfield Chemistry

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fax 01-972-952-9435. AbstractFormation fluid influx into cement slurries immediately after placement presents not only a short-term problem, for example losing the slurry due to shallow water flows, but also presents a long-term problem, for example gas flow and pressure buildup behind the casing. It is critical that cement slurries be designed carefully when such problems are anticipated. Cement slurries that often offer the best solution to resist the formation influx are those that do not gel while being pumped then gel/set and gain strength rapidly once placed. These are sometimes referred to as "right-angle set" cements and should possess the following attributes in laboratory design testing:• Maintains a low rheological profile while pumping for lower ECDs. • Predictable thickening and set times.• Retains the ability to transmit hydrostatic pressure under static conditions until the cement is ready to gel/set. • Short gel to set time under static conditions, often termed "transition time." • Short waiting on cement (WOC) time.This paper shows that although a cement slurry having a "right-angle set" may ensure the first two benefits, it does not always guarantee the latter two when present behind a casing. For example, some slurries might reach thickening time and become unpumpable rapidly, but strength development may not occur until long afterward, due to a time lag between thickening and hydration time (set time) of cement. In such cases, slurry should be designed such that the thickening time and hydration time are essentially identical. Novel slurries that maintain low rheological profiles while the slurry is being placed, then set and gain strength quickly due to cement hydration afterward, have been developed for a variety of densities and downhole temperatures. Results from laboratory and related field case histories will be presented.

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Section: A Cement Slurry May Have a Right-angled Setmentioning

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Designing Cement Slurries for Preventing Formation Fluid Influx After Placement

Santra

Reddy

Antia

2007

Proceedings of International Symposium on Oilfield Chemistry

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“…through the cement slurry creating permanent channels. The Transition Time (TT) is defined in literature (Murray et al, 2004) as the time between the start of gel strength build up and the point when the SGS Limit Value (from 50 to 250 Pa, or approximately 100 to 500 lb/100 sq. feet) is reached.…”

Section: Determination Of Slurry Thickening Timementioning

confidence: 99%

Cement slurries for sealing casing in boreholes with increased risk of gas migration

Rzepka¹,

Kremieniewski²,

Kędzierski³

2019

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A cement job is one of the most important operations carried out during the drilling of wells. Further functioning of the well depends on the correct execution of the cement job (for instance, in case of a failed cement job, further hydrocarbon deposit production may turn to be difficult or simply impossible). The article presents the issues of the cement slurry technology deployed for sealing shallow boreholes with an increased risk of shallow gas migration. Oil and Gas Institute-National Research Institute has developed a number of cement slurry formulations characterized by properly adjusted density, gelling and bonding time, which will allow the creation of a tight barrier in the borehole annulus that prevents the production fluid from leaking to the surface. Properly modified (with the aid of natural rubber latex or nanosilica) cement slurries based on Portland cement CEM I 42.5 are suitable for use in cement jobs carried out in shallow drilling wells. Particularly advantageous technological parameters have been obtained for cement slurries containing about 0.5-1% nano-SiO 2. The optimal water-cement ratio for these formulas was at the level of about 0.50-0.52. Both latex-containing and nano-SiO 2-containing samples were characterized by a very advantageous course of the gelation plot (static build-up of gel strength). Their TT transition times amounted to several tens of minutes (which is a proof of high ability to prevent gas migration from shallow gas accumulations). Bonding times of the tested slurries can be successfully controlled using acceleration agents commonly used in the industry. Slurries that had been tested using the Vicat apparatus were characterized by a bonding time in the range from approximately 100 up to 280 minutes. As a result, depending on the anticipated length of the cementing job, the required bonding time can be appropriately adjusted. Compressive strength after 7 days of hydration was high (for samples with the addition of latex, they were about 22-23 MPa, for nano-SiO 2 slurries around 29-31 MPa). Due to their good technological parameters, the cement slurries developed at Oil and Gas Institute-NRI could be used in the process of cementing casing strings, e.g. in the Carpathian Foreland, where there is a shallow gas accumulation hazard.

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“…Besides, it must not exceed fracturing pressure of the formation to avoid losses. 1 3. Loss circulation: jobs must be designed so that frac pressure during the pumping is not exceeded.…”

Section: Introductionmentioning

confidence: 99%

“…Cement slurries in the liquid phase transmit full hydrostatic pressure, and, as it starts to develop sufficient gel strenght to become self-supporting, they loose the ability to transmit full hydrostatic pressure, and, during this stage, if the pore pressure is greater than this hydrostatic pressure, gas/fluid can percolate through the slurry forming a channel. This transition time concept is defined as "the period from 100 SGS (when fluid intrusion into the gelled cement can occur) until 500 SGS (the slurry developed sufficient gel strength to prevent fluid migration into the cement column) 1 . Slurries are to be designed in such way in order to reduce this transitional time, to minimize the possibilities of gas/fluids migration.…”

Section: Introductionmentioning

confidence: 99%

Ultralightweight and Gas Migration Slurries: An Excellent Solution for Gas Wells

Mata

Dı́az

Villa

2006

Proceedings of SPE Annual Technical Conference and Exhibition

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThis paper shows the excellent results obtained using ultra lightweight and gas migration slurries (ULWGMS) on wells of San Joaquin and Santa Rosa fields, located in Anaco City, Eastern Venezuela.There are several gas fields in Anaco area, with complex wells, due to their low frac gradients, pressurized water zones, depressurized gas zones, H 2 S and CO 2 content, clay sands, and, in some cases, presence of micro fractures. These sands are also bounded by interbedded shales, with trapped gas and water, experiencing larges amount of losses of mineral oil mud, during drilling.All these characteristics contributed to unsuccessful primary cement jobs in the past, attributed to inappropriate slurry designs, with unsuitable properties to deal with all the above factors. Statistics showed that 2 out of 3 wells in this field failed due lost circulation issues, requiring remedial cementing to address gas control, and water migration. Ultra lightweight slurries were conceived, with adequate mechanical properties (flexible and tension strengths), in addition to providing H 2 S and CO 2 resistance.The first 9.2 ppg ultra lightweight slurry was first used in 2003 in San Joaquin field, and indicated good isolation, by logs runned.Subsequently, ultra lightweight slurries with densities from 9 to 11 ppg have been applied in 18 different wells in Anaco area, showing excellent zone isolation results, demonstrated by low water cut, and good bond logs.

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Transition Time of Cement Slurries, Definitions and Misconceptions, Related to Annular Fluid Migration

Cited by 20 publications

References 0 publications

Designing Cement Slurries for Preventing Formation Fluid Influx After Placement

Designing Cement Slurries for Preventing Formation Fluid Influx After Placement

Cement slurries for sealing casing in boreholes with increased risk of gas migration

Ultralightweight and Gas Migration Slurries: An Excellent Solution for Gas Wells

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