Lessons Learnt and Experiences Gained During Two Years of Field Monitoring, 
Data Integration and Reservoir Management: A Case History of the Mauddud 
Waterflood, North Kuwait

Chetri, H.B.; Al-Anzi, Ealian H.D.; Al-Rabah, Abdullah; Al-Dashti, Hussain; Al-Mutawa, Majdi; Chakravarthi, Ravula; Brown, Matthew R.; Isby, John; Clark, Andy

doi:10.2523/83961-ms

Cited by 10 publications

(5 citation statements)

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“…The thief zones are often located stratigraphically near the Mauddud B/C boundary and in the E zone according to previous studies (Chetri et al, 2003;Azim et al, 2003). They can also occur locally in other zones like MaB, MaD and MaF.…”

Section: Thief Zone Characterizationmentioning

confidence: 88%

“…It seemed difficult to identify the thief zones from conventional open-hole logs. The examined cores have often shown shattered or missing sections at or near the thief zones implying possible fracture development (Chetri et al, 2003). Core observations made in the Mauddud reservoir in an adjacent field indicated that fractured layers are the principal type of thief zone (Azim et al, 2003).…”

Section: Introductionmentioning

confidence: 96%

“…However, the water production increased significantly due to early water breakthrough in various layers in certain wells. Efforts have been made to recognize the thief zones using core, logs and PLT data (Chetri et al, 2003, Azim et al, 2003. It seemed difficult to identify the thief zones from conventional open-hole logs.…”

Section: Introductionmentioning

confidence: 99%

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Detecting Thief Zones in Carbonate Reservoirs by Integrating Borehole Images with Dynamic Measurements

Najeh

Lantz³

et al. 2008

SPE Annual Technical Conference and Exhibition

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One of the key issues in creating a good reservoir model in carbonate reservoirs is the identification of the horizontal permeability conduits-"thief zones" -if any. In the Sabriyah field in Kuwait, dynamic measurements showed evidence of thief zones in the Mauddud formation. Early water breakthrough has occurred in some wells. Previous studies indicated that it was very challenging to detect the thinly layered thief zones using conventional openhole logs. This paper describes a methodology of recognizing the different types of thief zones in the Mauddud carbonate reservoirs u sing high-resolution image logs with calibration from core and dynamic measurements and by integrating image logs with nuclear magnetic resonance (NMR) and conventional openhole logs.The Mauddud carbonates are Early Aptian in age and consist of grainstones, wackstones, and mudstones deposited in a ramp setting. Observations from production logging tool (PLT) and production data indicated that there are a few thief zones in different levels within the vertical Mauddud sequence. A previous core study shows that the fractures in Mauddud formation are short (<10 cm) and concentrated in diagenetically cemented layers. The fractured thin layers are believed to be the principal type of thief zone. Another type of thief zone is associated with better-developed vuggy porosity. This study shows both fractured and vuggy porosity-related types of thief zones can be potentially detected through integration of high-resolution image logs with PLT, NMR, and conventional logs. In addition, methodologies of estimating fracture permeability and porosity-related permeability based on logs are also proposed. The log-estimated permeability determined using this approach fits better with the production profile and can then be used to evaluate the thief zones in a more quantitative manner.

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Section: Thief Zone Characterizationmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 96%

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Detecting Thief Zones in Carbonate Reservoirs by Integrating Borehole Images with Dynamic Measurements

Najeh

Lantz³

et al. 2008

SPE Annual Technical Conference and Exhibition

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“…6 It is positioned above the Burgan sand and below the Wara formation (Figure 2). Mauddud is well known in the region for its numerous thief zones.…”

Section: Formation Characteristicsmentioning

confidence: 99%

Establishing Higher Oil Production Capabilities: Engineered Approach Achieves Longest Lateral Hole Section in Kuwait

et al. 2013

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Kuwait Oil Company (KOC) is analyzing the feasibility of utilizing extended reach drilling to achieve a long lateral section to increase oil production in northern Kuwait. Several attempts were made to accomplish the objective with roller cone and PDC bits on various directional tools with limited success. The major problem was short bit life/cutting structure durability and steerability issues in the difficult Mauddud carbonate reservoir. A drilling optimization initiative would benefit the entire northern Arabian basin because Mauddud is an important oil reservoir with uniform thickness and extensive regional distribution.Offset analysis showed three to four TCI bits were required to drill 3000 ft of lateral hole section. PDC bits display increased durability making up to 2500 ft of hole but were pulled for low ROP and unacceptable drilling inefficiency before reaching TD. A second PDC was required to finish the lateral and gain sufficient access to the reservoir. Before the optimization project, the longest single run with PDC was 2935 ft. The average footage drilled by roller cone TCI is approximately 1500 ft with average PDC footage around 2500 ft.To improve PDC bit performance, a rock strength program was run to identify the unconfined compressive strength (UCS) of Mauddud for use in an FEA-based modeling system. The software pegged the formation's UCS range between 9-15 kpsi with peaks up to 24 kpsi. Analogous rock sample files were selected and laboratory tests were performed to duplicate fundamental shearing action under the appropriate confining pressures. The resulting data was entered into the modeling system and simulations were performed with a baseline PDC to identify how lithology influences the bit/BHA and to investigate was to mitigate destructive drillstring dynamics.The engineering study produced a six-bladed PDC that drilled the longest lateral interval (5250 ft) in Kuwait through Mauddud. The bit displayed excellent steerability and completed the hole section without losing ROP. This resulted in 100% footage improvement against offset PDC runs and is more than 150% better than the best TCI performance. The completed well has provided a 200% increase in production capabilities making up to 4500 bbls/day.

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“…Chetri et al (2003) and Azim et al (2003) used core, logs and injection profiles/production profiles to understand the vertical distribution of the water injected/oil produced and to identify thief zones. Feng et al (2010) used well test method to quantitatively identify thief zones between wells, and to estimate parameters of the reservoir.…”

Section: Introductionmentioning

confidence: 99%

Thief zone identification based on transient pressure analysis: a field case study

Yang

2015

J Petrol Explor Prod Technol

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Thief zones are generally a channel with high absolute permeability. However, a not very strict theory analysis shows that neglecting the effect of variant of water saturation on formation of thief zone in mature reservoirs cannot explain some thief zones in mature reservoirs. This paper focuses on the effect of water saturation on thief zone development for wells in mature reservoirs with areal permeability heterogeneity. The water saturation increases in high permeable channel with water passing through, which gradually leads to higher value of water phase relative permeability, and thus leads to higher value of effective permeability kÁk rw in the high permeable channel than that in surrounding reservoir. The gradually increasing difference of effective permeability kÁk rw between permeable channel and surrounding reservoir would be the main reason for formation of thief zones in mature reservoir. The oil-water two-phase numerical model based on PEBI (perpendicular bisection) gridding is used to study effect of variant of water phase saturation on formation of thief zone. We find that relatively small pressure change and not obvious bump in pressure derivative curves during shut-in are indicators of thief zones in mature reservoirs. This finding provides a further understanding for the thief zone development and also gives us a guidance to interpret the buildup pressure data in the mature sandstone reservoirs. A field case study verifies the effectiveness of the new explanation.

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Lessons Learnt and Experiences Gained During Two Years of Field Monitoring, Data Integration and Reservoir Management: A Case History of the Mauddud Waterflood, North Kuwait

Cited by 10 publications

References 0 publications

Detecting Thief Zones in Carbonate Reservoirs by Integrating Borehole Images with Dynamic Measurements

Detecting Thief Zones in Carbonate Reservoirs by Integrating Borehole Images with Dynamic Measurements

Establishing Higher Oil Production Capabilities: Engineered Approach Achieves Longest Lateral Hole Section in Kuwait

Thief zone identification based on transient pressure analysis: a field case study

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