Single Step Enzyme Treatment Enhances Production Capacity on Horizontal Wells

Stanley, F.O.; Rae, Phil; Troncoso, Juan C.

doi:10.2118/52818-ms

Cited by 28 publications

(8 citation statements)

References 22 publications

(22 reference statements)

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“…Thus, they attack the formed mudcake in a uniform way. Weak organic acids can be incorporated also into enzyme solutions to enhance their mudcake removal (Stanely et al 1999. This combination of enzymes and organic acids results in dual attack on both the calcium carbonate and the polymer components of the filter cake.…”

Section: Introductionmentioning

confidence: 99%

A Novel Enzyme Breaker for Mudcake Removal in High Temperature Horizontal and Multi-lateral Wells

AlKhaldi

Ghosh

2011

SPE Asia Pacific Oil and Gas Conference and Exhibition

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Effective removal of drilling-mud filter cake during well completion is essential to reduce the formation damage caused by drilling activities in many production and injection wells. This task is very difficult to achieve, especially in horizontal/multilateral wells. Harsh chemical treatments (acids, oxidizers, and chelating agents) have been used extensively to conduct water-based mudcake cleanup treatments. However, these approaches have been limited due to the associated high corrosion rates and un-even mudcake removal. With their controlled reaction with the mudcake, mild chemical nature, better health, safety and environmental (HSE) profile, enzymes provide an excellent alternative to harsh chemical treatments in high temperature formations. However, their use has been limited to relatively low temperature applications due to their instability at elevated temperature values.In this work, two enzymatic systems were evaluated: old α-amylase system and new structurally reinforced α-Helix system. The old enzyme was found to form a potentially damaging precipitate at reservoir temperature above 100 o C. The degree of this damage was assessed using size-matching technique and core-flood experiments. This potential of secondary formation damage was drastically reduced in the new improved enzyme system. Enzyme denaturing was minimized by protecting the catalytic center using preferential hydration of proteins with a Polyol.The effectiveness of the new system was proven in the lab through comparative tests. Bioassay by reducing sugar estimation showed better biopolymer hydrolyzing capability of the new system at higher temperatures. In contrast to old enzyme system, core-flood experiments, conducted at high temperatures, using new enzyme system, showed the enzyme denaturing did not occur and the core oil permeability increased at stabilized pressure. In addition, this paper will also highlight the advantages and disadvantages of each enzyme system in terms of stability, compatibility, and mudcake damage reversal.

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Section: Introductionmentioning

confidence: 99%

A Novel Enzyme Breaker for Mudcake Removal in High Temperature Horizontal and Multi-lateral Wells

AlKhaldi

Ghosh

2011

SPE Asia Pacific Oil and Gas Conference and Exhibition

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“…bhtp = bottom hole treating pressure bfpd = barrels of fluid per day bopd = barrels of oil per day ESP = electrical submersible pump k ro = relative permeability to oil k rw = relative permeability to water mgal = one thousand gallons Drive Pipe -20" @ 369' "X" Landing Nipple W/2.813" ID @ +/-300' 13 …”

Section: Discussionmentioning

confidence: 99%

“…As part of the completion practices in the field, Aida A-9 was initially stimulated using 2000 gals of a polymer specific enzyme solution to remove drill-in fluid (DIF) damage from the drilling operations, a standard operation in the area to remove and dissolve polymer and calcium carbonate particles 13 .…”

Section: Case History -Aida A-9mentioning

confidence: 99%

Matrix Acidizing Horizontal Gravel-Packed Wells for Fines Damage Removal

Stanley¹,

Troncoso²,

Martín³

et al. 2000

SPE/CIM International Conference on Horizontal Well Technology

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“…Another explanation is the buffering action that results from the addition of an organic acid and its salt. 20 It is also interesting to note that the lowest rock solubility was obtained with the emulsified acid.…”

Section: Effect Of Chloride-free Formulae On Rock Dissolutionmentioning

confidence: 99%

Lab Testing and Field Application of a Large-Scale Acetic Acid-Based Treatment in a Newly Developed Carbonate Reservoir

Nasr‐El‐Din¹,

Lynn²,

Taylor³

2001

Proceedings of SPE International Symposium on Oilfield Chemistry

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractA large-scale acetic acid-based stimulation treatment was developed to remove drilling mud filter cake in vertical wells in a newly developed carbonate reservoir. The wellbore stability of this weakly consolidated carbonate formation can easily be reduced by contact with HCl-based acids. Extensive lab testing had indicated that the formation is mechanically weak, becomes brittle upon contact with acids and produces large amounts of fine particles that can cause severe damage. Furthermore, a chloride-free acid formula was required to minimize interference with the pulsed-neutron logs (PNL). A special acid treatment was needed to remove the damage while maintaining the integrity of the formation.Several tests were conducted in the laboratory to evaluate both regular and emulsified acetic acid and non-acid formulae (mainly EDTA). Initially, two acid formulae were selected for field application. The first used 10 wt% acetic acid in an emulsified form, while the second formula was based on 10 wt% regular acetic acid in combination with additives. Further lab and field-testing indicated that the emulsified form might pose a problem in the presence of fine inter-matrix dolomite particles. Therefore, the treatment performed in the field focused on the use of 10 wt% acetic acid with several waterwetting agents (mainly surfactants and mutual solvent).The acetic acid treatment was applied in five vertical wells in this field using a coiled tubing unit. Pressure build-up tests after the treatment indicated that the acid was successful in removing the filter cake in all cases. Neither fine particles, nor any type of emulsion was noted in the well flowback samples. However, well productivity after the treatment was found to be a strong function of the lithofacies of the formation (e.g., chalk versus packstone). Wells with high reservoir quality rock (i.e., packstones with a permeability of 20-30 mD), demonstrated excellent pressure response after the treatment. Flowing wellhead pressures were increased significantly. Wells with low reservoir quality showed a moderate increase following the treatment.

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Single Step Enzyme Treatment Enhances Production Capacity on Horizontal Wells

Cited by 28 publications

References 22 publications

A Novel Enzyme Breaker for Mudcake Removal in High Temperature Horizontal and Multi-lateral Wells

A Novel Enzyme Breaker for Mudcake Removal in High Temperature Horizontal and Multi-lateral Wells

Matrix Acidizing Horizontal Gravel-Packed Wells for Fines Damage Removal

Lab Testing and Field Application of a Large-Scale Acetic Acid-Based Treatment in a Newly Developed Carbonate Reservoir

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