Software, Fluids, and Downhole Tools for Successful Sand Cleanouts in Any Wellbore Geometry Using Small Coiled Tubing

Gilmore, Todd Gerard; Leonard, R.L.; Steinback, Scott L.

doi:10.2118/97080-ms

Cited by 11 publications

(6 citation statements)

References 13 publications

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“…Several cleanout techniques have been developed over the years, these include stationary circulation, wiper tripping (1,2,(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) , reverse circulation (19)(20)(21)(22) , sand vacuuming technology (23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)36,37) , and venturi sand/junk bailers (4,22,(38)(39)(40) .…”

Section: Sand Cleanout Methodsmentioning

confidence: 99%

“…Wiper Trip Hole Cleaning (2,(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) A comprehensive experimental test program conducted over the past 15 years (7)(8)(9)(10)(11)(12) has investigated solids transport for both stationary circulation and wiper trip cleanouts. The effect of multiphase flow, rate of penetration (ROP), deviation angle, circulation fluid properties, particle density and size, fluid rheology, pipe eccentricity, wiper trip speed, and nozzle type on solids transport was examined in detail.…”

Section: Conventional Hole Cleaning Methodsmentioning

confidence: 99%

“…Based on this research, an effective solids-cleanout methodology/process using CT [see Figures 4(a) and (4c)] has been developed and proven by field operations (1,2,4,6,(14)(15)(16)(17)(18) . This patented (13) methodology is embodied in a comprehensive solids-transport simulator (10) and the method is further enhanced by a specialized downhole cleanout tool ( Figure 5).…”

Section: Conventional Hole Cleaning Methodsmentioning

confidence: 99%

“…The cleanout fluid is circulated through low energy uphole-facing nozzles which reentrain solids that have settled on the low side of the hole for subsequent transport along the wellbore. The methodology/process takes advantage of improved hole cleaning from jetting in the uphole direction, while tripping out of hole at a computed wiper trip speed (14)(15)(16)(17)(18) . "Wiper tripping," as defined in this paper, is the movement of the CT and bottom hole assembly (BHA) out of the hole a certain distance or to surface, while continuously circulating cleanout fluid through the wash nozzle or circulating valve if used.…”

Section: Conventional Hole Cleaning Methodsmentioning

confidence: 99%

“…In some cases, the sand can only be removed from highly deviated/horizontal large wellbores by the combination of using fluids with high solids-suspension property and the wiper-trip technology (1,11,16) . For pressure-depleted reservoirs (2) , nitrified fluids have to be circulated.…”

Section: Conventional Hole Cleaning Methodsmentioning

confidence: 99%

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Sand Cleanouts With Coiled Tubing: Choice of Process, Tools and Fluids

Li¹,

Misselbrook²,

Sach³

2010

Journal of Canadian Petroleum Technology

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Summary Cleaning fill from wellbores is the most common coiled tubing (CT) application. The process is a function of multiple variables including fluid properties, flow velocities, wellbore geometry and deviation, pipe eccentricity, particle properties, fill penetration rate and wiper trip speed. Removing fill from wells with low bottom hole pressures (BHP) can be challenging especially if wells are completed with smaller diameter production tubulars which significantly reduce circulation flow cross-section and choke flow(1). Such challenges are further compounded by high deviation or horizontal well trajectories especially in large diameter wellbores. A variety of cleanout methods have been developed in the past, often incorporating high circulation rates, special fluids, wiper trips, or reverse circulation to remove solids. Many of these conventional sand cleanout methods often apply excess hydrostatic pressure on the formation, resulting in lost circulation in pressure depleted reservoirs. The conventional solution to overcome excess hydrostatic pressure has been to include nitrogen to reduce fluid density and thus lessen the hydrostatic head; however, sand vacuuming technology using a concentric coiled tubing (CCT) with a downhole jet pump is an alternative technique for removing fill without placing a hydrostatic load on the reservoir. This paper reviews the individual sand cleanout systems and discusses the advantages and limitations related to each method. In recent years, cleaning sand using the wiper trip method has become the preferred technique. However, an appropriate pump rate and reservoir pressure are needed to maintain a proper return flow rate to carry the sands to the surface. For pressure-depleted reservoirs completed with horizontal wells, a sand vacuuming system can be used to efficiently remove the debris without circulating nitrogen and without high pump rates. When the fill cannot be removed from large-diameter deviated wellbores using conventional low-cost cleanout fluids, then fluids with high solids suspension capability (under shear conditions) in conjunction with wiper tripping may be an economical option. The main application for the reverse circulation technique is cleaning sand from large diameter wellbores when the necessary pump rates for conventional "forward" circulation are not achievable. A venturi junk bailer is often used to retrieve larger or heavier material which cannot be circulated out by traditional methods. Field cases are provided, demonstrating how to select the proper cleaning method and how to efficiently remove sand from a wellbore based on both operational and logistical conditions.

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Section: Sand Cleanout Methodsmentioning

confidence: 99%

Section: Conventional Hole Cleaning Methodsmentioning

confidence: 99%

Section: Conventional Hole Cleaning Methodsmentioning

confidence: 99%

Section: Conventional Hole Cleaning Methodsmentioning

confidence: 99%

Section: Conventional Hole Cleaning Methodsmentioning

confidence: 99%

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Sand Cleanouts With Coiled Tubing: Choice of Process, Tools and Fluids

Li¹,

Misselbrook²,

Sach³

2010

Journal of Canadian Petroleum Technology

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Challenging Wellbore Cleanouts With Coiled Tubing Made Easy With Computer Modeling Technology

et al. 2006

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Well bore cleanouts have been performed for many years with coiled tubing and it may be said that the cleanout operation is one of the most routine services performed in the coiled tubing industry; but until recently design was no more than a rule-of-thumb approach. Sufficient information is now available to facilitate informed decisions and achieve reliable engineering solutions, utilizing a sophisticated particle transport model. A methodical thought process, based on extensive research and mathematical modeling, will be presented for designing specific well bore cleanouts in a challenging offshore field in the Middle East. Case histories from a number of wells are documented detailing the conclusions from each. Laboratory analysis was performed on samples collected from the cleanout operations to further optimize and validate the design process. It is the intent of this paper to demonstrate the importance of sound engineering design, aided by comprehensive computer modeling technology. Introduction Particle transport is a process to remove material such as formation fines, drill cuttings, sand, etc. out of wells. The use of coiled tubing to convey circulation fluids and tools to facilitate a thru-tubing cleanout is considered standard industry practice in the oilfield. Typical fluids used to facilitate these operations are water, brine, and water based gellant systems. Hydrocarbon fluids may also be pumped, however inherent HSE issues must be addressed when pumping hydrocarbon fluids. It may be safe to say that "cleanouts with coiled tubing is the number one application". Having said that, one may also say that the industry has really lacked a good understanding of how to effectively transport particles. The fact that regular operations are conducted on a daily basis globally does not necessarily mean that everyone conducting cleanout operations has a full understanding of how to effectively design and execute a particular cleanout. Based on a comprehensive experimental test of solids transport in the previous studies1–7, a patented fill cleanout process technology8 with CT has been developed and proved by field operations9–13. The process includes running CT into the well while circulating fluid using a nozzle with a "high energy" jetting action pointing forwards down the well to stir up the particulate solids and allow the CT to reach a target depth or bottom of the well (penetration stage). When the bottom or desired depth is reached, the hole can then be cleaned either by circulating a fluid while keeping the CT stationary (circulation stage) or by pulling the CT out of the wellbore with continuous circulation (wiper trip stage), or by a combination of these stages. In the wiper trip mode, a reversing jetting nozzle with low energy is used to circulate the fluids and to create a particle re-entrainment action to enhance agitation of the solids and then entrain the particulates in suspension for transport out of the wellbore while pulling the CT out of the hole. The reverse jetting action along with a controlled pump rate and POOH speed can produce a solids transport action which cleans the hole completely by keeping the solids in front (upward) of the end of the CT in continuous agitation. The low energy nozzles have a low pressure drop which allows for higher flow rates and results in improved cleanout efficiency. This method and tool is more efficient than existing methods since the process may be limited to one pass or sweep with the option of resetting the tool for repeated cycles if required. Factors Affecting Clean Out Operations There are several factors which affect the clean out operation and hence the efficiency of the clean out job. When designing a clean out job, those factors should be taken into consideration to achieve a successful clean out job Fill type: Fill type plays an important role in sand clean out design. Fill type can be fines (small grain size) or coarse (large grain size). The fill type affects fluid selection, penetration and wiper rate determination. The larger grain size is more challenging to transport in a cleanout job. The density is related to the circulation time (how long to circulate at TD to move heavy solids out of well). The fundamental reason for circulation and turbulent flow is to prevent solids falling back into the well when performing a wiper trip.

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Effective Heavy Post-Fracturing Proppant Cleanout with Coiled Tubing: Experimental Study and Field Case History

Li¹,

Bayfield²,

Paton

2006

SPE Annual Technical Conference and Exhibition

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractBauxite ceramics are a high strength proppant, which is often used for fracturing stimulation in deep and hot wells. Due to its higher specific gravity (3.5 -3.6), it is very challenging to design and execute the post-fracturing proppant cleanout with coiled tubing (CT) successfully in the highly deviated large wellbore.In a sand cleanout with CT the solids are moved by two modes of transport: circulation and wiper trip, in which the localized fluidization is caused by jet turbulence. The jetting turbulence is produced by the down hole wash tool, and as the CT is pulled from the hole it fluidizes and propels the solids in the direction of the wellhead. Some of these solids may stay in suspension and be circulated out of the well depending on the flow velocities, hole geometry and fluid choice. The remainder will tend to fall out of the flow channel downstream from the wash tool. These solids will be continually refluidised by the movement of the wash tool. The speed with which the wash tool can be pulled out of the hole is a complex function of the choice of fluid, flow velocities, hole geometry, hole deviation and the physical properties of the particles. When conditions result in complete removal of the solids, the corresponding maximum value of the CT speed is defined as the optimum wiper trip speed.In this study, the solids transport test results with bauxite in a full scale flow loop are summarized and four case histories performed on both subsea and land wells are presented. The engineering, implementation and challenge of CT post-fracturing sand cleanout for each individual field case are discussed. The paper also describes how to use a customized down hole switchable wash nozzle and a sophisticated solids transport computer modeling software to optimize the post-fracturing sand cleanout process with 100 % removal efficiency.

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Software, Fluids, and Downhole Tools for Successful Sand Cleanouts in Any Wellbore Geometry Using Small Coiled Tubing

Abstract: TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe use of coiled tubing to clean sand from well bores remains one of the industries major areas of activity in well intervention. Recent research work programs have focused on sand transport and cuttings bed modeling with both Newtonian

Cited by 11 publications

References 13 publications

Sand Cleanouts With Coiled Tubing: Choice of Process, Tools and Fluids

Sand Cleanouts With Coiled Tubing: Choice of Process, Tools and Fluids

Challenging Wellbore Cleanouts With Coiled Tubing Made Easy With Computer Modeling Technology

Effective Heavy Post-Fracturing Proppant Cleanout with Coiled Tubing: Experimental Study and Field Case History

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