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Abstract KOC management has created an experienced team to test and complete new Jurassic wells drilled in North Kuwait field. Testing & completion has been a challenging task in handling Jurassic reservoirs because of deep wells, HPHT conditions, heavey mud weights and sour volatile oil/gas condensate. All wells were tested either with Polished Bore Receptacle (PBR) or retrivable/permanent packer designed to achieve the objectives. New Jurassic discovery wells were also tested on long term basis using Early Production Facility (EPF) in order to conclude, evaluate and confirm the overall potential of Jurassic formation for further production enhancement and delineation/ development work. This team has developed optimized practices based on the experiences gained in testing and completion of more than 20 exploratory/delination wells drilled in Jurassic reservoirs. These optimized practices have been applied in several deep/HPHT wells drilled in Kuwait and tested safely & economically. It illustrates a very valuable experience of KOC's exploration process in deep well testing & completion. This paper describes practices followed, problems faced and remedial actions while testing & completion of deep/HPHT Jurassic wells. Details of procedure developed, techniques applied in perforating, activation, stimulation, fracturing, short-term/long term testing is also presented in this paper.
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > North Kuwait Jurassic (NKJ) Fields > Marrat Formation > Upper Marrat Formation (0.98)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > North Kuwait Jurassic (NKJ) Fields > Marrat Formation > Sargelu Formation (0.98)
Flow Path Characterization: A Deterministic Approach for Reconciliation of Flow Capacity Changes from Matrix and Fractures Productivity in Deep Jurassic Reservoirs in North Kuwait
Acharya, Mihira N. (Kuwait Oil Company) | Chakravorty, Sandeep (Schlumberger Oilfield Eastern Limited) | Rao, Dhiresh G. (Schlumberger Oilfield Eastern Limited) | Joshi, Girija K. (Kuwait Oil Company) | Pradhan, San P. (Kuwait Oil Company) | Rao, Narhari S. (Kuwait Oil Company) | Singh, J. R. (Kuwait Oil Company) | Dashti, Qasem M. (Kuwait Oil Company)
Abstract The Deep carbonate reservoirs of North Kuwait are broadly divided into deeper assemblage consisting of diagenitically modified dolomitic layer and shallower fractured-laminated tight limestone and Kerogen units. It is a challenge to establish and quantify the known phenomenon of dynamic changes in the flow path characteristics and properties of the reservoir rocks, as the natural stability condition are altered by production of reservoir fluid. The parameters of the flow path characterization become more uncertain in case of deep HP/HT digenetically altered reservoirs and fractured-tight limestone with laminated kerogen, then similar to the North Kuwait deep reservoirs. In this study an integration of static data such as, borehole image, core and petrophysical evaluation with time lapse dynamic reservoir parameters like production, pressure data from buildup and pressure transient analysis was carried out to understand the flow path characteristic changes. A deterministic approach has been used to characterize the reservoir flow system and to estimate the fracture aperture for each time step. Thus the time dependent alternations in the flow path properties such as reduced fracture aperture and linked causative phenomena have been studied with multiple scenarios. A detailed inventory and analysis of various well intervention operations between the time lapse measurements was carried out to distinguish the natural vs. work over induced causatives of flow path changes. This has assisted proper calibration of fracture properties for the static conditions, dynamic simulation and history matching. This workflow has also optimized the application of appropriate reservoir health checkups and remedial interventions. Cases of two representative wells completed in each of the deep reservoir assemblages are presented as examples to demonstrate the study.
- Geology > Geological Subdiscipline (1.00)
- Geology > Rock Type > Sedimentary Rock > Carbonate Rock > Limestone (0.47)
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying > Borehole Seismic Surveying (0.34)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > North Kuwait Jurassic (NKJ) Fields > Marrat Formation > Upper Marrat Formation (0.98)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > North Kuwait Jurassic (NKJ) Fields > Marrat Formation > Sargelu Formation (0.98)
First Successful Multistage Completion Paves the Way for Optimized Field Development of the Jurassic Formations of North Kuwait
Ahmed, Zamzam (Kuwait Oil Company) | Al-Otaibi, Yousef (Kuwait Oil Company) | Bloushi, Taha (Kuwait Oil Company) | Fidan, Erkan (Kuwait Oil Company) | Sharma, Siddhartha (Kuwait Oil Company) | Pradhan, San Prasad (Kuwait Oil Company) | Al-Mutairi, Mubarak (Kuwait Oil Company) | Al-Failakawi, Abdul Aziz (Kuwait Oil Company) | Shaikh, Ahmed Karim (Shell Kuwait Exploration and Production) | Quint, Edwin (Shell Kuwait Exploration and Production)
The HPHT, sour, deep, fractured and not so fractured carbonate Jurassic formations within the North Kuwait cluster of fields present extraordinary challenges in driving towards an optimized field development that maximizes liquid recovery and meet the gas production aspirations for the state of Kuwait. The Middle Marrat reservoir has been developed to date with cased and perforated liner completions across the 500-700ft pay. However due to the high permeability contrast between the different reservoir flow units, the low permeability zones are typically not contributing. This is further exasperated with the inability to effectively acid stimulate large proportion of the net pay with a single stage bullhead treatment especially when the contrast in permeability between the various flow units is higher than one order of magnitude. Key to successful reservoir management of the Middle Marrat whilst maximizing well capacity to meet the production aspirations is to implement a completion and stimulation strategy that maximizes flow contribution from as much of the net pay as possible. Single stage bullhead matrix acid stimulation treatments like those executed in the past will only stimulate the top decade of permeability. The current 4-1/2" cemented completion'plug and perf' standard will require intensive well intervention to set and drill out plugs in order to selectively stimulate individual zones. To develop an alternative completion and stimulation strategy for developing Middle Marrat, the first 4-1/2" multistage ball activated sleeve completion system has been deployed successfully in a Middle Marrat deviated development well. 2 out of 3 stages installed have been acid stimulated and flow tested showing excellent results. The operational experience and learnings acquired from the project have provided the necessary confidence to the organization to deploy the technology in tight gas and unconventional reservoirs within North Kuwait, but also challenge the existing cemented'plug & perf' completion and stimulation approach for the development of the more conventional Middle Marrat reservoirs. 2 SPE-187580-MS
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Raudhatain Field > Upper Burgan Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Raudhatain Field > Mauddud Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Raudhatain Field > Lower Burgan Formation (0.99)
- (2 more...)
Conductivity Enhancement and Productivity Restoration of Deep North Kuwait Jurassic Gas-Condensate Well by Using Effective HRMA Stimulation Technique
BinMotlaq, Hind (Kuwait Oil Company) | Ahmed, Zamzam (Kuwait Oil Company) | AlSaeed, Abdullah (Kuwait Oil Company) | Fidan, Erkan (Kuwait Oil Company) | AlMutawa, Majdi (Kuwait Oil Company) | Salem, Abrar (Schlumberger) | Slama, Hedi (Schlumberger)
Abstract Achieving sustainable gas and condensate production from carbonaceous North Kuwait Jurassic Gas (NKJG) reservoirs has been challenging due to multi-dimensional inflow/outflow complications under restrictive operating downhole conditions. Production from the NKJG reservoirs has strategic importance for the State of Kuwait, where the formations are deep and sour, and produce gas-condensate and volatile oil, in which the produced fluids contain from 2 to 8% H2S and 1 to 3% CO2. High reservoir pressure of up to 12,000 psi is widespread trapped below an over-pressured salt structure. NKJG reservoirs have high temperature of ~275F and have been recently completed with monobore completions, to optimize overall commingled well performance and to ensure operational optimization of future well interventions. Differential depletion has had significant consequences in well and reservoir management including the design and execution of stimulation treatments, particularly the "high rate matrix acidizing (HRMA)" applications. In addition, vertical variations in lithological and mechanical rock properties contribute to drilling challenges which are progressively exacerbated as the deepest zones continue to produce most of the hydrocarbons whereas other potential horizons are not exploited at similar rates. Monobore completions have been deployed so that each flow unit could be segregated and stimulated separately, starting from the bottom, moving uphole as each stage is treated, activated, tested and isolated using drillable bridge plugs. After all zones are completed, the bridge plugs are drilled out using coiled tubing mills and commingled production is established from all zones. To overcome this complex technical challenge while utilizing the funds and resources efficiently, the team in charge of the project developed a novel method of assessing the zones similar in reservoir characteristics and generated a "bullheaded HRMA treatment design" concept which was applied in the subject well while stretching the length of the perforation interval to a gross 216 ft that can be effectively covered with sound wellbore diversion methodology using particulate chemical diverters as well as leak-off control diverters. The custom-designed fluid train was tailored to effectively stimulate each conductivity unit, followed by diversion into the subsequent stages. The perforated interval length has been stretched to 285 ft in subsequent wells based on the success of this well. The completion and intervention history of the subject well is covered in this paper followed by the successful field implementation of the HRMA application as a case study, and to share the learnings and recommendations providing pre-stimulation and post-stimulation production logging comparisons. As an additional challenge, the HRMA treatment overcame the heavy near-wellbore damage created during a workover fishing operation due to the well-kill with heavy drilling fluid. The results are confirmed by calibrated nodal analysis assessment providing evidence of the success in deploying this technology in unconventional tight gas reservoir of less than 10 mD permeability. Achieving optimal inflow distribution along vertically varied flow zones has enabled the asset to deploy this systematic approach in other new wells in the NKJG while saving significant cost and time.
- Asia > Middle East > Kuwait (0.93)
- Asia > Middle East > UAE > Abu Dhabi Emirate > Abu Dhabi (0.15)
- Geology > Rock Type (0.48)
- Geology > Geological Subdiscipline > Geomechanics (0.34)
Abstract The North Kuwait Jurassic Complex consists of five fields, each with three identified reservoirs within the naturally fractured Jurassic carbonate formation. These reservoirs contain multiple fluid types at near critical conditions with flow properties ranging from fracture to matrix dominated flow. Multiple-scenarios production forecasts, using dual-porosity, dual-permeability reservoir simulation models, are required to prepare an optimal development plan for the complex. In this paper we discuss available options to simulate multiple reservoirs which, although isolated based on the current compartmentalization understanding of the complex, they cannot be run in isolation because of global production targets. We show that using multiple-reservoirs integration through controller to couple the separate reservoir models through global production targets/limits provides an optimal simulation framework for the NKJC: flexibility and computational efficiency of multiple segment models and comprehensiveness of full filed simulation modeling.
- Asia > Middle East > Kuwait (0.72)
- North America > United States (0.68)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > North Kuwait Jurassic (NKJ) Fields > Marrat Formation > Upper Marrat Formation (0.98)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > North Kuwait Jurassic (NKJ) Fields > Marrat Formation > Sargelu Formation (0.98)
- Reservoir Description and Dynamics > Reservoir Simulation (1.00)
- Reservoir Description and Dynamics > Fluid Characterization > Phase behavior and PVT measurements (1.00)
- Reservoir Description and Dynamics > Fluid Characterization > Fluid modeling, equations of state (0.95)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Drillstem/well testing (0.88)