Successful Application of a Fit-for-Purpose Acid Program in the Tengiz Field

Ussenbayeva, Khadisha Yerikovna; Utebaeva, Dinara; Molesworth, Gregg R.; Dunger, Darrin; Akwukwaegbu, Chinedu Franklyn; Salikhov, Timur M.; Kamispayev, Akylbek; Zielinski, Matthew Bernard; Yakovlev, Timofey; Savin, Artemiy; Aglyamov, Mansur

doi:10.2118/160804-ms

Cited by 6 publications

References 8 publications

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A New Strategy to Explore Tight Oil/Gas Reservoirs "Fit for Purpose Acid Fracturing"

Hegazy

Salem²,

Shedid

et al. 2013

All Days

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Oil and gas exploration in carbonate reservoirs typically utilize conventional techniques in perforation, matrix acidizing stimulation and well testing. Currently, oil companies have moved to more marginal reservoir targets. Application of these techniques has often yielded disappointing results and tighter zones are often abandoned for more promising target intervals.With increases in oil and gas production targets, operators are being forced to investigate more marginal reservoir layers for reserves and production potential. The real challenge facing oil industry today is that successful exploration requires a change in drilling, completion and stimulation techniques currently utilized by operators.Marginal reservoirs can have lots of resource potential and reserves, but may require horizontal well drilling, and/or multiple stage hydraulic fracturing to achieve economic production targets. This type of strategy is more expensive than conventional method(s) and is proven in some circles as potentially risky and many of these risks must be addressed and mitigated. In an effort to reduce risks and costs associated with the exploration process, a new stimulation strategy has been adopted for tight intervals to explore and appraise these intervals using vertical wells prior to going to horizontal wells. This paper presents and analyzes oil exploration well case study in which a new strategy has been applied and evaluated. The study also demonstrates that this approach can lead to new resource discoveries, better reservoir understanding and improved well and completion design for future appraisal wells. Moreover, the paper highlights some of the additional challenges that this strategy may evoke and shows how these challenges may be overcome in the future.

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A New Strategy to Explore Tight Oil/Gas Reservoirs "Fit for Purpose Acid Fracturing"

Hegazy

Salem²,

Shedid

et al. 2013

All Days

View full text Add to dashboard Cite

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Improved Understanding of Acid Wormholing in Carbonate Reservoirs Through Laboratory Experiments and Field Measurements

Burton

Nozaki

Zwarich

et al. 2018

SPE Annual Technical Conference and Exhibition

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A comprehensive study on wormholing has been conducted to improve the understanding of matrix acidizing in carbonate reservoirs. This work is a continuation of previous work (Furui et al. 2012a, 2012b). An analysis of additional experimental results as well as field measurements is provided to reinforce and extend the wormhole penetration model and productivity benefits provided by Furui et al. (2012b). A series of small block tests and one large block test under geomechanical stresses has been conducted to characterize wormholing in outcrop chalk samples. In addition, field data including acid pumping data as well as post-stimulation pressure falloff data has been collected and analyzed to evaluate stimulation effectiveness. Pressure buildup data from stimulated wells has also been analyzed to evaluate the sustainability of the acid induced skin benefits. Production logging data has been used to investigate whether created wormhole networks have remained stable or have collapsed under production stresses. To statistically analyze the data more comprehensively, the new data was also compared to the data from other field data available in the literature. The following conclusions are drawn from an analysis of the laboratory data and field data: 1) a skin value of −4 is achievable in carbonate reservoirs by matrix acidizing, 2) the negative acid skin is relatively stable under production stresses, 3) the wormhole penetration model is proven to successfully simulate matrix acidizing processes in both laboratory scale and field scale work, 4) the small and large block laboratory tests re-confirmed wormholing efficiency which was discussed as a scale effect in previous studies, 5) an understanding of the possible range of wormhole penetration has allowed us to improve field acid treatments and reduce the risk of connecting to water. This comprehensive study includes acid linear core flooding tests, small block tests, large block tests and field measurements to thoroughly analyze acid wormholing in carbonate rock. The database can be very useful information for understanding, benchmarking and optimizing future completion/stimulation design.

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Improved Understanding of Acid Wormholing in Carbonate Reservoirs through Laboratory Experiments and Field Measurements

et al. 2019

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SummaryA comprehensive study on wormholing has been conducted to improve the understanding of matrix acidizing in carbonate reservoirs. This work is a continuation of the previous work by Furui et al. (2012a, 2012b). An analysis of additional experimental results, as well as field measurements, is provided to reinforce and extend the wormhole-penetration model and productivity benefits provided by Furui et al. (2012b).A series of small-block tests and one large-block test under geomechanical stresses have been conducted to characterize wormholing in outcrop-chalk samples. In addition, field data including acid-pumping data and post-stimulation pressure-falloff data have been collected and analyzed to evaluate stimulation effectiveness. Pressure-buildup data from stimulated wells have also been analyzed to evaluate the sustainability of the acid-induced skin benefits. Production-logging data have been used to investigate whether created wormhole networks have remained stable or have collapsed under production stresses. To statistically analyze the data more comprehensively, the new data were also compared to field data available in the literature.The following conclusions are drawn from an analysis of the laboratory data and field data: (1) A skin value of −4 is achievable in carbonate reservoirs by matrix acidizing; (2) the negative acid skin is relatively stable under production stresses; (3) the wormhole-penetration model is proved to successfully simulate matrix-acidizing processes in both laboratory-scale and field-scale work; (4) the small- and large-block laboratory tests reconfirmed wormholing efficiency, which was discussed as a scale effect in the previous studies; and (5) an understanding of the possible range of wormhole penetration has allowed us to improve field acid treatments and reduce the risk of connecting to water.This comprehensive study includes acid-linear-coreflooding tests, small-block tests, large-block tests, and field measurements to thoroughly analyze acid wormholing in carbonate rock. The database can be very useful information for understanding, benchmarking, and optimizing future completion/stimulation design.

show abstract

Successful Application of a Fit-for-Purpose Acid Program in the Tengiz Field

Cited by 6 publications

References 8 publications

A New Strategy to Explore Tight Oil/Gas Reservoirs "Fit for Purpose Acid Fracturing"

A New Strategy to Explore Tight Oil/Gas Reservoirs "Fit for Purpose Acid Fracturing"

Improved Understanding of Acid Wormholing in Carbonate Reservoirs Through Laboratory Experiments and Field Measurements

Improved Understanding of Acid Wormholing in Carbonate Reservoirs through Laboratory Experiments and Field Measurements

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