Development of a New Crosslinked-HEC Fluid Loss Control Pill for Highly-Overbalanced, High-Permeability and/or High Temperature Formations

Chang, Frank; Ali, Syed A.; Cromb, John; Bowman, Monte; Parlar, Mehmet

doi:10.2118/39438-ms

Cited by 21 publications

(3 citation statements)

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“…These particles create an impermeable filter cake that can be removed with an acidic external breaker. Another approach has been to create a high-pH zirconium crosslinked HEC gel sufficiently strong to stop fluid loss in high-permeability (Ͼ1000 md) formations with no indication of pore-space invasion (Chang et al 1998). The delayed crosslinked fluid system has excellent rigidity and elasticity.…”

Section: Traditional Polymer Gel Systemsmentioning

confidence: 99%

Controlling Losses When Recompleting Low-Pressure Reservoirs

et al. 2015

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The challenge in many permeable water sensitive subhydrostatic reservoirs is to avoid the loss of completion fluid when completing or working over wells. It is not unusual to lose up to 1,000 bbl of completion fluid, resulting in a 20% to 50% reduction in production.Several different approaches have been used to prevent these losses. The most common is viscous fluid-loss control pills with sized particulates, such as calcium carbonate, which often requires a further treatment to remove the solids. An alternative is a solids-free crosslinked viscous polymer pill, which must be spotted and kept in position across the reservoir prior to it crosslinking.To overcome the limitation of conventional fluid-loss control pills, a low-viscosity system was developed. The system is composed of a viscous disproportionate permeability modifier (VDPM) with sized synthetic polymer particles and fibers, which, with time and temperature, degrade into organic acids. The VDPM reduces the effective permeability to the water-based fluids, and the sized particles create an impermeable filter cake. When the particles degrade, the organic acid acts to break any remaining polymer. The system can either be bullheaded or spotted in the wellbore prior to perforating and effectively seals the formation for several days.The fluid-loss pill has been used successfully in more than 25 wells. The volume of fluid lost into the formation is often less than 1 bbl, and production is maintained after the workover. The technique has made it possible to selectively stimulate new intervals or recomplete wells with an average increase of more than 240 BOPD, whereas, historically, a decline in production was not uncommon.

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Section: Traditional Polymer Gel Systemsmentioning

confidence: 99%

Controlling Losses When Recompleting Low-Pressure Reservoirs

et al. 2015

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“…Organic acid (formic, acetic, and citric acids) and mineral acid (HCl) solutions are used as external breakers while oxidizers are used as internal breakers for delayed breaking. Break time of crosslinked gel can be tuned by physical and chemical parameters (Ross et al 1999;Chang et al 1998). The organic and mineral acid solutions are not preferred by many operators because they break the gel plugs vigorously and in an uncontrolled way, which can result in fluid loss into the formation and then reaction of the formation with the remaining amount of acid.…”

Section: Introductionmentioning

confidence: 99%

Guidelines for Breaker Selection in High Viscosity HEC Based Gel Plugs

Songire

Uppuluri

2014

Abu Dhabi International Petroleum Exhibition and Conference

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Operators can face multiple challenges during various completion and workover operations, one of which is fluid loss into the formation. Ensuring minimal fluid loss is of the utmost importance, particularly in highly permeable zones as expensive completion fluids are pushed into the porosity of the formations, usually resulting in perm damage.Available techniques for controlling fluid loss primarily include mechanical or chemical options. Mechanical techniques, although widely used successfully, have drawbacks, such as plug failure at high-pressure/high-temperature HP/HT conditions, requiring an additional trip. With industry needs for lower costs and better fluid-loss control (FLC) systems, many chemical systems have been developed to help overcome such problems associated with mechanical systems. These chemical systems include linear polymers, CaCO 3 ϩ polymer gel, sized salt ϩ polymer gel, and oil soluble resins. Although effective, these are either expensive or can leave residue behind as a result of incomplete break, causing formation damage. Crosslinked hydroxyethyl cellulose (CLHEC) based gel plugs can provide effective FLC and are used post-perforating in addition to before and after gravel pack operations. They consist of highly viscous, solids-free crosslinked gel, prepared in medium and low density brines. CLHEC based gel plugs form a filter cake, which can be removed by internal and/or external breakers as a means for cleanup.To obtain a desired break time, understanding the behavior of the breaker under bottomhole temperature (BHT) conditions is vital. This study focuses on investigating various internal and external breaker actions at temperatures ranging between 120 and 270°F. The laboratory data provided in this paper demonstrates the performance of various breakers, such as oxidizers, delayed-release acids, and selfdegrading particulate systems in low and medium density brines. The information provided in this study offers a guideline for an appropriate breaker selection in hydroxyethyl cellulose (HEC) based gel plugs.

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“…In addition, linear gels require removal by either an internal breaker (a chemical that breaks down the polymer chain) or by an external wash (i.e., acid treatment) (Ross et al 1999). Crosslinked gels are generally HEC derivative (Chang et al 1998) or CMHEC-based systems (Cole et al 1995). They function by forming a filter cake at the formation or by entering the permeability of the formation and stop losses by plugging the pore throats with the crosslinked, gelled structure.…”

Section: Introductionmentioning

confidence: 99%

Successful Field Implementation of a Novel Solids-Free System to Control Fluid Loss During Overbalanced Workover Operations in Southern Argentina

et al. 2013

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During workover and completion operations, even a small overbalanced hydrostatic pressure can result in a significant loss of fluid to the formation, especially in high-permeability formations. This situation becomes even more drastic in depleted reservoirs, horizontal wells, or in zones that have been previously fractured and packed. Controlling fluid loss into the formation is of critical importance during overbalanced workover operations to minimize near-wellbore (NWB) damage invasion by the completion fluid, which can yield problems associated with poor wellbore cleanout and loss of hydrocarbon reserves. In addition, fluid loss can increase costs associated with rig time and treatments devoted to restore the initial condition of the formation. In many hydrocarbon fields in southern Argentina, controlling fluid loss before NWB cleanout treatments is challenging because it can cause pressure differential sticking of the coiled tubing (CT) and/or inability to pump the treatment into the desired interval. This paper presents the successful field application of a novel solids-free fluid-loss (SFFL) system during wellbore cleanouts in the Cerro Dragon oilfield, which is located on the west side of San Jorge Gulf (SJG) basin in the Chubut Province of Argentina.The SFFL system relies on water-soluble polymer that decreases matrix permeability to aqueous fluids, limiting leakoff into treated zones. This polymer immediately adsorbs to the surface of the rock, eliminating the need to shut the well in. In addition, this system does not require the use of breakers or a cleanup stage to reestablish hydrocarbon production once the workover operation has been performed. Laboratory test data show the capability of the material to control fluid leakoff and achieve high levels of regained permeability to hydrocarbons. Traditional techniques to minimize fluid loss use solids or viscous pills, although it has been amply documented that these systems can damage the formation if not properly removed after the treatment.To date, about 200 treatments have been performed with this novel SFFL system. The paper discusses field results from the application of this system during overbalanced workover operations in Argentina, including the job design and posttreatment results. This system has been proposed for returning partial and total loss to full circulation in overbalanced operations, such as (1) lost-circulation events occurring during cementing, fracturing and drilling, (2) well intervention cleanouts by CT and hydraulic workover (HWO), (3) gravel packing, (4) replacement of artificial lift equipment (i.e., electrical submersible pumps), and (5) overbalanced tubing-conveyed perforating (UTCP).

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Development of a New Crosslinked-HEC Fluid Loss Control Pill for Highly-Overbalanced, High-Permeability and/or High Temperature Formations

Cited by 21 publications

References 0 publications

Controlling Losses When Recompleting Low-Pressure Reservoirs

Controlling Losses When Recompleting Low-Pressure Reservoirs

Guidelines for Breaker Selection in High Viscosity HEC Based Gel Plugs

Successful Field Implementation of a Novel Solids-Free System to Control Fluid Loss During Overbalanced Workover Operations in Southern Argentina

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