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Abstract Sabiriyah Upper Burgan (UB) is a giant clastic reservoir in North Kuwait undergoing development efforts with water flood. Productivity indices as per historical data indicated these to be less than adequate and mismatching with the intrinsic reservoir permeabilities. This was a puzzle till a comprehensive review of the past pressure build up data was made and the results integrated with the-then perforation practices. More than 85% of the wells showed formation damage with a positive skin of +2 to +7, as per PBU data. Efforts were made to perform mud acid jobs without much success. After detailed review and performance analysis, recommendations were made to perforate new producers with TCP under balance, in addition to improvements in drilling mud chemistry. Subsequent PBU results of these wells indicated negative skin, which was also supported by better PIs. The situation became a serious issue during initial phase of water flood and Injectivity tests. Injectors showed poor Injectivity indices. Though there had been multiple reasons for poor Injectivity, formation damage due to progressive plugging of pore throats was one of the major contributors. Detailed review of the dynamic behavior of the injectors led to the recommendations for improving the injection water quality by proper filtration, back flowing of the injectors prior to injection start-up and performing proppant frac jobs, if warranted. The implementation led to significant improvement in Injectivity. Phase-1 injection in the pressure depleted crestal area is in progress since last 3 years, thus sustaining production staying above the bubble point pressure. Simultaneous to above, pore throat studies were conducted, leading to the conclusion that the pore throat size is very small with inherent risk of progressive plugging of injectors with time. In order to have life-of-field solution to Injectivity issues, recommendation was made to inject above parting pressure during the full field expansion of the water flood in 2010–11, on the basis of the results of Step Rate tests. The case history of understanding and combating the formation damage in UB was a giant leap for rationalizing the way forward for its full fledged development. Background Upper Burgan reservoir in Sabiriyah field was discovered in 1950s. The Albian age Upper Burgan sandstone represents deposition in an overall paralic environment. The reservoir comprises a complex series of tidal, estuary, deltaic, valley fill and shoreface sands interbedded with semi continuous shales. The paleo-shoreline is interpreted as having a NW-SE trend with the field areas located slightly offshore. There are three dominant sand-prone facies present in the Upper Burgan.
- Geology > Sedimentary Geology > Depositional Environment (0.88)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (0.36)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Upper Marrat Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Sargelu Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Sabiriyah Mauddud (SAMA) Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > SAMA Formation (0.99)
- Well Completion > Completion Installation and Operations (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Waterflooding (1.00)
Opportunistic Fluid Sampling and Analysis to track reservoir souring in water flooded operations in North Kuwait reservoirs C - Implications for the future
Al-Marri, Salem Sml (Kuwait Institute for Scientific Research) | Alkafeef, Saad F. (College of Technological Studies) | Chetri, Hom B. (Kuwait Oil Company) | Al-Ghabdan, Asma'a (Kuwait Oil Company) | Al-Anzi, Ealian H.D. (Kuwait Oil Company)
Abstract Reservoir souring while water flooding North Kuwait reservoirs has been predicted by modeling studies in the past. One of Sabiriyah Mauddud wells showed up H2S as first indication of reservoir souring, which was an alarm bell for production facilities designed for only sweet crude. Surface/ Bottomhole fluid samples were required to confirm whether it is localized or reservoir-wide. In order to track reservoir souring and monitor on continuous basis, a process for tracking of reservoir souring annually was developed and initiated for the first time in 2006. Subsequently, this has been made part & parcel of fluid study requirements each year. As sea water is being injected into traditionally sweet reservoir like Sabiriyah Mauddud, some degree of reservoir souring is expected due to Sulfate reducing bacterial (SRB) activity, as was projected happen sometime in 2005 in wells, needing monitoring/ mitigation actions. Expected H2S levels being very low (50–200 ppm), risk of loosing and not capturing these concentrations using conventional samplers/ bottles due to absorption/ reaction with the metallurgy of the samplers was felt, thus posing a challenge for obtaining a representative bottomhole sample for the analysis of H2S. A comprehensive sampling program was made jointly by KOC & KISR, using the non-reactive internally coated samplers for capturing bottom hole samples; performing the onsite analysis, followed by immediate shipment to the local fluid analysis laboratory and conduct all necessary analysis with expert supervision & care. Value was added to North Kuwait Water flood management by timely knowing the onset of reservoir souring. The analysis also led the way forward for the review of chemicals dosages; interventions needed in case of H2S occurrence; inputs to the future facilities and the requirements of further modeling studies. Background: Sabiriyah Mauddud, a super giant depletion drive oil reservoir in North Kuwait, is undergoing massive development efforts, with a planned enhancement in oil production through phased pattern water flood. The Phase 1 development covers the crystal area of the structure, which is the focus for current development efforts through twelve number of inverted 9-spot water flood patterns.
- North America (1.00)
- Asia > Middle East > Kuwait (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Lifecycle > Treatment (0.47)
- Water & Waste Management > Water Management > Lifecycle > Disposal/Injection (0.31)
- North America > Canada > Alberta > Western Canada Sedimentary Basin > Alberta Basin > Deep Basin > Caroline Field > Cardium Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Upper Marrat Formation (0.94)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Sargelu Formation (0.94)
- (7 more...)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Waterflooding (1.00)
- Reservoir Description and Dynamics > Fluid Characterization (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (1.00)
Opportunistic Pressure Data Gathering Campaign During Production Shut Down—Added Insight Into the Water Flood Response and Pressure Connectivity in a Highly Heterogeneous Clastic Reservoir in North Kuwait
Baroon, Bodoor Ali (Kuwait Oil Company) | Chetri, Hom B. (Kuwait Oil Company) | Al-Anzi, Ealian H.D. (Kuwait Oil Company)
Abstract Upper Burgan is a sandstone reservoir in North Kuwait, which is a depletion drive reservoir predominantly, with a very weak aquifer support. The reservoir has cumulatively produced about 7% of oil in place since its discovery. Almost 90% of production in the historical past came from the crestal area leading to a rapid decline in reservoir pressure. The initial reservoir pressure was about 3800 psia and it is continuously declining to bubble point pressure. Recently water flood has been initiated at three of the injectors in the crestal area to reverse the trend of pressure decline. Pressure monitoring is the key for the monitoring heterogeneous Upper Burgan reservoir, currently under water flood. This has been achieved in three ways during past 5 years: Time lapse SBHP monitoring; isochronal full field pressure surveys during reservoir shutdown and PBU/PFO /RFT/ data integration with PLT & Production tests. Extensive data gathering has enabled the team to enhance the water flood response. Additionally, smart maps using OFM have also been created as tracking tools. The pressure monitoring & analysis has helped in effective water flood management as well as sustaining the production rates for this challenging heterogeneous reservoir. Also, the extensive data acquired and analyzed has added value to the comprehensive channel description, reservoir continuity and simulation model update for this reservoir. The objective of the paper is to share the approach adopted by us and experiences gained during last 5 years of water flood monitoring in North Kuwait. Background: Upper Burgan reservoir in Sabiriyah field was discovered in 1950s. The Albian age Upper Burgan sandstone represents deposition in an overall paralic environment. The reservoir comprises a complex series of tidal, estuary, deltaic, valley fill and shoreface sands interbedded with semi continuous shales. The paleo-shoreline is interpreted as having a NW-SE trend with the field areas located slightly offshore. There are three dominant sand-prone facies present in the Upper Burgan.'Carbonaceous sand', which is a fine - medium grained sand with typically excellent petrophysical properties (porosity 22–25%, permeability >400 md). 'Bioturbated sand', which is very fine to fine grained facies with reservoir quality e highly variable. 'Heterolithic sand', is typically very fine to fine grained & is abundant in the Upper Burgan, with erratic reservoir quality is erratic.
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Upper Marrat Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Sargelu Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Sabiriyah Mauddud (SAMA) Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > SAMA Formation (0.99)
Integrated Reservoir Management Approach Beats the Impact of Reservoir Heterogeneity, Injectivity Challenges and Delayed Waterflood in Upper Burgan Reservoir in North Kuwait: A Case History
Chetri, Hom B. (Kuwait Oil Company) | El-Sabry, Abdul Aziz (Kuwait Oil Company) | Al-Mufarej, Mishal | Al-Anzi, Ealian H.D. (Kuwait Oil Company)
Abstract Upper Burgan is a multi-layered reservoir in Sabiriyah Field of North Kuwait, currently undergoing initial phase of Water flood development. A highly complex reservoir with respect to reservoir heterogeneity; connectivity and structural compartmentalization based on detailed analogous study, the preliminary experience with the water flood performance was too dismal to achieve the target injection rates. A detailed channel mapping work has been completed which has enhanced the sub surface understanding to add value to the ongoing drilling/ production and injection plans. Challenges posed by the heterogeneity and compartmentalization coupled with poor Injectivity initially slowed down the pace of the water flood development of the reservoir. The Integrated Reservoir Management (IRM) approach with a distinctive strategy for depletion & pressure support for each of its segments has immensely helped the short term production build-up and sustaining the rates. The strategy is focused at producing the high reservoir pressure segments and managing the production from the depleted crestal part in tandem with ongoing water injection; aggressive pressure monitoring and cooperation from the operational teams. The current/ short term drilling plan has been set to target the segments with higher reservoir pressures for well placement. The synergy with drilling activities in overlying Mauddud and underlying Lower Burgan reservoirs has helped in valuable data acquisition and swapping of wells for short term production requirements opportunistically. The case history in the paper illustrates how the IRM approach in Upper Burgan is helping to manage & sustain the production rates at higher levels than predicted in the past, beating the impact of reservoir heterogeneity; Injectivity challenges and delayed water flood and at the same time, staying above the bubble point pressure. Background Upper Burgan reservoir in Sabiriyah field was discovered in 1950s. The Albian age Upper Burgan sandstone represents deposition in an overall paralic environment. The reservoir comprises a complex series of tidal, estuary, deltaic, valley fill and shoreface sands interbedded with semi continuous shales. The paleo-shoreline is interpreted as having a NW-SE trend with the field areas located slightly offshore. There are three dominant sand-prone facies present in the Upper Burgan.The first facies is 'carbonaceous sand'. This is a fine - medium grained sand with typically excellent petrophysical properties (porosity 22–25%, permeability >400 md). This facies is interpreted to have been deposited in an estuarine/tidally influenced environment often with high rates of deposition. The thickness of this facies can reach 40 feet however, 10–20 feet is more typical. The second sand-prone facies is 'bioturbated sand'. This very fine to fine grained facies is thought to represent a dominantly marine environment. Reservoir quality can be highly variable. The thickness of the facies is on average 20 feet. The third facies type, 'heterolithic sand', is typically very fine to fine grained. This facies type is abundant in the Upper Burgan. Its presence represents a number of environments including mouthbar, tidal flats, tidal channels, etc.. Reservoir quality is erratic. Due to its laminated nature vertical permeability is low.
- Geology > Sedimentary Geology > Depositional Environment > Transitional Environment (0.88)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (0.54)
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Lifecycle > Disposal/Injection (0.92)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Upper Marrat Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Sargelu Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Sabiriyah Mauddud (SAMA) Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > SAMA Formation (0.99)
Abstract Mauddud is a major hydrocarbon bearing formation in Sabiriyah field of North Kuwait. This carbonate reservoir is under depletion drive with no aquifer support and is currently producing under water flood with average water cut of 26 %. Water injection started in 2000 under 9-spot water flood pattern system and the water flood is maintaining a good pressure support in the reservoir close to initial reservoir pressure and well above bubble point pressure. However, the water production increased significantly due to premature water breakthrough, particularly in edge wells. This has led to an immediate need for implementing effective water shut off techniques for decreasing water production at the subsurface level to balance and better control the sweep of the reservoir. Consequently eight edge wells were identified after detailed studies of production history, PLT, water cut trend etc and taken up for water shut off jobs during the year 2005–06. Although in many of these wells, there were clear indications of water break through from bottom perforations, the option of plug back cementation could not be attempted for completion constraint as Mauddud was completed in short string of all the eight dual wells selected. The methodology adopted was cement squeeze followed by selective perforation keeping away from the possible high permeability "thief" zones based on the PLT analysis mainly. Every effort was made to ensure the integrity of the cement squeeze by conducting a positive pressure test followed by negative test during workover job. Utmost emphasis was given for a successful negative test @ 500 psi which is the representative operating draw down for Mauddud producers. Consequently squeeze jobs had to be repeated several times with special types of cements in certain cases, in pursuit of successful positive and negative tests and thereby accomplishing an effective squeeze job. The water shut off jobs on these wells had mixed success and an in depth analysis of pre-post job scenario on these wells is presented in this paper. Introduction: The Sabriyah structure is an elongated, north trending, faulted anticline with numerous grabens and associated relay ramps covered over an area of about 237 Sq. Km. The fault throws vary from less than 30 feet to more than 160 feet. The structural dip varies from up to 8 degrees on the eastern flank to 3–4 degrees on the western flank. The original oil/water contact is unknown and is most likely to vary by fault block. A schematic representation of field lithology is given in Fig1. Sabriyah field consists of three major reservoirs:Mauddud Upper Burgan Lower Burgan Mauddud is a major reservoir of the filed characterized by a very stiff Limestone formation with low compressibility rock, inter-granular porosity, with very little or negligible development of secondary porosity. Eleven reservoir zones were identified in Mauddud and named from MaA to MaJ. The reservoir has a very weak and inactive aquifer. There was little to no need for water shut-off requirement felt in SA-Mauddud till the onset of water flood in 2000, and following few years, as most of the wells were producing water free oil. However as a result of ongoing waterflooding, the water production increased significantly and need was felt not only for enhancing water handling capacity at the surface, but also searching for sound techniques of decreasing water production at the subsurface level.
- Geology > Structural Geology > Fault (0.88)
- Geology > Structural Geology > Tectonics (0.54)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Upper Marrat Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Sargelu Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Sabiriyah Mauddud (SAMA) Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > SAMA Formation (0.99)
- Well Completion > Completion Installation and Operations > Perforating (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Waterflooding (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Conformance improvement (1.00)
Abstract Sabiriyah Mauddud (SA MA), a super giant depletion drive oil reservoir in North Kuwait (NK), is undergoing massive development efforts, with a planned enhancement in oil production through phased pattern waterflood. The Phase 1 development covers the crestal area of the structure, which is the focus for current development efforts through 12 inverted 9-spot patterns. This paper outlines the successful integration of subsurface, water handling, well surveillance and production operations teams across the NK asset to significantly improve the operating procedure for waterflooding the SA MA reservoir. This effort required a new way of managing this reservoir in NK: a comprehensive approach of balancing voidage with injection, conducting extensive surveillance/analysis within the reservoir to assess the efficacy of various courses of action and, most significantly, adjusting various teams' "key performance indicators" to align injection and production allowables with sound reservoir management principles. The health of the waterflood is regularly checked and monitored through revision of production/injection allowable and pattern balancing. An innovative unified information management system was used to monitor voidage replacement ratio (VRR) to provide a basis for pattern balancing. A very extensive surveillance operation provides the data necessary to monitor individual pattern balance and watercut performance, optimize areal sweep efficiency by adjusting injection and production allowables, assist in planning water shutoff operations, and design new completions. Time lapsed monitoring and the surveillance data indicates the reservoir is relatively well connected. Pattern VRR, pressures, and watercuts were somewhat out of balance prior to engaging in this effort. However, after applying the new management approach, individual waterflood pattern balance is significantly improved and the field-wide VRR is around 1.2. All of these activities have led to the enhanced understanding of the waterflood behavior and the model updates. Sound reservoir surveillance and waterflood management procedures implemented within a diverse group of teams that have performance goals aligned with "best practice" has resulted in effectively re-balancing this major waterflood. This effective integration of teams retains the flexibility to adjust for an ongoing development of this super giant field. This paper also brings out the case history of waterflood management in a super giant carbonate reservoir and the challenges met during the last seven years since the commissioning of the waterflood in year 2000. Introduction Mauddud reservoir located in Sabiriyah field (NK) was discovered in 1950s. First commercial oil production from this carbonate reservoir started back in 1957. Operating under depletion dive with no natural aquifer support, the well spacing varies with close well spacing in the crestal area and wider spacing in the flank area. Early in the life of the Mauddud reservoir, KOC decided to limit production until some pressure maintenance system was installed. After a successful 5-spot pattern waterflood pilot (1997–1999), a full scale Sea Water Injection into 12 inverted 9-spot patterns was commenced in year 2000. Mauddud carbonate reservoir, an emerging relatively young 7-year-old waterflood, though has produced a cumulative of less than 2% of the original oil in place (OOIP) as of year 2007, will contribute an increasing and important portion of the future oil production from NK. SA MA reservoir is the largest North Kuwait reservoir in terms of OOIP, and reserves. Amongst 3 oil-producing reservoirs, which are at various stages of development, it is the largest contributor to Sabiriyah oil production, producing 40% of the Sabiriyah daily oil production. Mauddud oil API gravity is ranging between 24–30 degree.
- Asia > Middle East > Kuwait > Jahra Governorate (0.62)
- Asia > Middle East > Qatar > Arabian Gulf (0.40)
- Geology > Structural Geology (0.46)
- Geology > Geological Subdiscipline (0.34)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Upper Marrat Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Sargelu Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Sabiriyah Mauddud (SAMA) Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > SAMA Formation (0.99)
Abstract The new production logging tool string and interpretation technique were established in order to solve the surveillance limitations in the short string section of the dual completion wells. The logging program was initiated in Kuwait Sabriyah Field where there are two major producing formations: Mauddud Carbonate and Burgan Sandstone Formations. The wells were completed with dual production strings due to distinct fluid and reservoir properties in these formations. Water injection was implemented in Mauddud Formation in late 2000 after a successful waterflood pilot program. The wells having water injection are mostly located in the short string section of the dual completions. The monitoring of the water breakthroughs and finding the bypassed oil became crucial for the field development. Understanding of the reservoir required logging these sections. The conventional wireline logging was regarded as a difficult and unsafe operation due to complicated nature of the production strings and the risk of wireline logging tool entangling. The earlier practice was to utilize the workover rig and to remove the two production strings before performing any wireline logging in the well. This operation was not only costly and time consuming but also pausing the production from Burgan Formation. The new logging string and interpretation technique were developed to survey the short string section of the dual string completions without utilizing a rig. The logging operation consisted of conveying the production logging tool with a coiled tubing through the short string section of the dual completions. Flow profiles and water entries were confidently obtained in many wells with the new interpretation technique. This paper presents the history of the short string logging operations in the North Kuwait Fields and highlights the improved coiled tubing conveyed logging tool string and the recent interpretation technique in order to overcome the problems due to completion restrictions. Introduction The improved production logging tool string was utilized in the Mauddud Formation in order to identify the flow profile mainly to locate the water entry intervals. Mauddud Carbonate Formation in the North Kuwait is consisted of two large anticlines named as Sabriyah and Raudhatain Fields. Mauddud Carbonate Formation is located below Tuba Carbonate and above Lower and Upper Burgan Sandstone Formations. These formations are independent from each other and separated with clear petrophysical signatures. Mauddud Formation, containing no natural pressure support, has a production history of more than 40 years. The depletion drive mechanism causes the swift pressure decline in the field. Studies indicated that water flood with artificial lift would significantly improve the oil recovery in the Mauddud Formation. The focus in this article is the production logging applications in the Sabriyah Field. The following part summarizes the reservoir properties and production history of the field. Sabriyah Field has oil gravity ranging 18–26 °API, GOR varying 60–350 scf/bbl, porosity of 18–22%, permeability of 15–60 md, bubble point pressure of 300–1900 psia and oil viscosity at the bubble point ranging 2.5–15 cp. Uncertainties of the fluid type were eliminated with the extensive zonal sampling in the field. The PVT data illustrates that the oil has higher viscosities with the increasing depth hence showing the oil quality deterioration1. Figure 1 shows typical well logs in Mauddud Formation in Sabriyah Field. The seawater injection water flood program was designed to reduce the pressure depletion and increase the sweep efficiency. After successful water injection pilot project in Sabriyah Field, the water flood project was initiated with 12 inverted nine spot patterns having 250 acre spacing for each well at the crestal part of the reservoir in November 2000. Since the commencing of the waterflood more than 100 million bbls of treated seawater was injected from 12 injectors in about 50 km2 area.
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Upper Marrat Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Sargelu Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Sabiriyah Mauddud (SAMA) Formation (0.99)
- (8 more...)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Waterflooding (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
Integrating the Fluid Quality and Rock Description in Sabiriyah Mauddud Limestone in North Kuwait to rationalize the Waterflood development Strategy-A Case History
Chetri, H.B. (Kuwait Oil Co.) | Najeh, Hamad (Kuwait Oil Co.) | Al-Janaie, Dalal Ali (Kuwait Oil Co.) | Al-Mutawa, Majdi (Kuwait Oil Co.) | Chandran, T.P. (Kuwait Oil Co.) | Al-Anzi, Ealian H.D. (Kuwait Oil Co.) | Wells, John (Kuwait Oil Co.) | Cig, Koksal (Schlumberger)
Abstract The Sabiriyah Mauddud limestone of North Kuwait is a super giant depletion drive oil reservoir. Massive development efforts are underway, with a planned enhancement in oil production through phased pattern water flood. The Phase1 development addresses the crestal area (50 km2) of the structure, which was the focus for development efforts in the past. The Phase 2 development consists of all remaining peripheral acreage (200 km2), with immense reservoir rock & fluid uncertainties, leading to the identification of reservoir segments for re-appraisal through drilling & testing of new wells. The fluid description had been a challenge for the reservoir, especially in the mid flank and down flank areas with poor rock / fluid quality. The past data on fluid quality had been the average for the whole of the Mauddud unit perforated together. A serious data gap existed with respect to the vertical variation of the reservoir oil quality. Sampling of formation fluids has been historically not possible in the formation due to low permeability and sharp viscosity variation with depth, to fully develop and discover the potential of the formation. The permeability and viscosity combination of the formation has not allowed fluids to be sampled with a probe formation tester tool. The slick line sampling operation has been also attempted with nitrogen lifting without any result. In early 2002, in order to match the field development plan, formation tester with an inflatable dual packer module was utilized to achieve sampling. The operation was completed successfully in the 9 5/8" cased hole environment. Second half of the year, sampling was also achieved in 8.5" open hole conditions. Late 2002 and onwards, the sampling operation became part of the open hole logging program and the versatility of the wireline tester tool also allowed performing mini-DST and vertical interference applications in required wells. Re-appraisal & testing work, along with enhanced fluid description, led to the conclusion that a large segment within the Phase 2 area, originally considered as a regime of light oil - turned out to be viscous oil. Prior to progressing on the water flood development in Phase 2 area, significant amount of data was acquired through a rational placement of new wells so as to reduce the uncertainty on rock quality. Numerous injectivity tests / step rate tests were conducted, the results of which were suggestive of the concept of injecting above the formation parting pressure in down flank areas with poorer rock & fluid quality and design the facilities accordingly to meet the subsurface requirements. The earlier estimates of the water flood recovery were discovered to be quite optimistic as reflected by the latest full field reservoir simulation model runs. The above realizations changed the past outlook of development plan and led to the fine-tuning of the way forward. The paper proposes to share the unique experience & benefits of progressing through a phase development approach for this giant & challenging carbonate reservoir in North Kuwait. Introduction: Mauddud reservoir is a giant oil bearing carbonate reservoir in the Sabriyah field of North Kuwait (location map placed at figure-1). It is overlain by a minor carbonate reservoir viz. Tuba and underlain by Lower/ Upper Burgan reservoirs. The reservoir is comprised predominantly of mid ramp packstones. Presence of higher energy grainstones and floatstones typically result in higher permeability layers within the reservoir. Although there appeared relatively good lateral correlation between the facies types, the lateral continuity remained a major unknown. Major pressure barriers are stratigraphically confined and result from intense cementation - these barriers are laterally extensive. A number of potential flow baffles are also recognised, their effect on recovery is uncertain at this time. Sabriyah fluid movement appears to be dominated by the grainstone/packstone interval.
- Geology > Geological Subdiscipline (1.00)
- Geology > Rock Type > Sedimentary Rock > Carbonate Rock > Limestone (0.60)
- Energy > Oil & Gas > Upstream (1.00)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (0.46)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Upper Marrat Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Sargelu Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Sabiriyah Mauddud (SAMA) Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > SAMA Formation (0.99)