Carbonate Reservoirs

Recent IRT Work

Kuwait

  • IRT provided an on-site staff reservoir engineer for Mauddud Reservoir, Sabiriyah Field, Kuwait (3 years) Responsibilities included: leading team direction with regard to new development well locations, make recommendations on testing procedures for new well fluid properties and SCAL if necessary, evaluate of pressure transient analysis when new data was received and re-evaluate previous work to improve consistency of approach, integrate geologic information on historical well and model performance to improve reservoir understanding. Understand water injection issues and recommend improvements to profiles or mitigation of poor injection profiles. Maintain existing reservoir simulation model and use that model in support of ongoing reservoir management issues.
  • IRT provided an on-site staff reservoir engineer for Mauddud Reservoir, Raudhatain Field, Kuwait (1 year). Responsibilities included: leading team direction with regard to new development well locations, make recommendations on testing procedures for new well fluid properties and SCAL if necessary, evaluation of pressure transient analysis when new data was received and re-evaluate previous work to improve consistency of approach, integrate geologic information on historical well and model performance to improve reservoir understanding. Understand water injection issues and recommend improvements to profiles or mitigation of poor injection profiles.

Oman

  • Block 30, Oman - Fracture and petrophysical analysis of the Natih and Shuaiba formations. Correlate the distribution of fracture "swarms" identified in the fracture model with structure curvature, fault proximity, matrix properties, or stratigraphy. Geostatistical methods were used to distribute regions of fracture "swarms" and regions of "background" fracturing, and to distribute fracture properties within each of these two regions. Use numerical models of the quantitative test data available in the Hafar, Al-Sahwa, and Nadir well tests to "tune" the fracture properties in the conceptual models, both inside and outside of swarms. Build a simulation model of all of the pore-volume contributing to flow in the known gas reservoirs in Block 30 using the "most probable" properties identified in the data analysis and well test modeling. Use the model based on the "most probable properties" to determine and optimum set of locations and orientations for productions wells for the nine known reservoirs. Run sensitivities to the "most significant" uncertainties in the reservoir model description and operational constraints.

Mexico

  • Puerto Ceiba, Shuco-Colibri, Yachipa Fields - Worked on three large 3D seismic surveys in southern Mexico. Main objectives were to define structural framework, identify potential development well locations and exploration targets in Mesozoic fractured carbonate rocks. Study included integrating petrophysical processing of 180 wells, seismic interpretation of two 3-D seismic surveys, core studies, and borehole image interpretations into a comprehensive 14 layer model over a 32x36 km area using Landmark (OpenWorks, Zmap, SeisWorks, PetroWorks, and StratWorks) and GeoQuest software (CPS with FrameWork Modeling).
  • Carmito Field - Fracture characterization and reservoir simulation project in fractured carbonate gas condensate with limited water drive.
  • Catedral Field - Fracture characterization and reservoir simulation project in fractured carbonate gas condensate with limited water drive.
  • Cantarell Complex (Akal, Nohoch and Chac Fields) - Acted in an on-site advisory capacity for production engineering and reservoir engineering. IRT was involved in a multi-disciplinary integrated project team that started with 3-D seismic data and well logs, and resulted in an Eclipse reservoir simulation model. IRT provided guidance in planning future Enhanced Oil Recovery for the field and also performed an analysis of artificial lift using Petroleum Experts PROSPER software, and acted on behalf of PEMEX in outlining the planned artificial lift program to equipment suppliers. IRT proposed a combination of improved gas-lift and electric submersible pumps to improve production in the field.

United States

  • Eland Lodgepole Unit, North Dakota - Integrated Study (seismic, geology, petrophysics, engineering and reservoir simulation). The Eland Lodgepole reservoir is geologically complex in terms of porosity types and pore volume determination. A vuggy / fracture pore system results in a high effective permeability, which provides good productivity. Extensive geologic and engineering analysis performed in order to construct a dual-porosity reservoir simulation model for use in field development and operations management. The field is currently under waterflood and is expected to recover an extraordinarily high proportion of the original oil in place.
  • Paradox Basin (Island Butte and Cutthroat Fields), Colorado - These are ongoing integrated studies to characterize this field and define its extent. The reservoir is a large carbonate mound deposit, and has been re-defined by performing attribute analyses on 3-D seismic data. Estimates of total mound thickness and net pay thickness have been estimated in this fashion. Each new reservoir description has been input into a VIP compositional model, the updated model is matched to actual field performance, and the resulting model used to establish and update the development and management plan for the field. In this way, the model acts as a living tool for the management of the reservoir.
  • Dolphin Field, North Dakota - IRT has been the principal reservoir engineering consultant on the field through the discovery, development, gas cycling miscible displacement and performance monitoring phases of the life of this implementation of this volatile oil reservoir. The reservoir is a salt plugged carbonate with highly directional permeability. Equation of state fluid property characterization was performed on extensive laboratory tests in order to determine miscibility conditions and develop an accurate compositional reservoir simulation model. Development and operational alternatives are continuously evaluated including recompletions, infill drilling, water injection for sweep control, and blowdown scenarios. Each alternative was evaluated within gathering system, process plant, and compression constraints.
  • Brush Lake Field, Gunton Reservoir, Montana - Integrated study of a fractured carbonate reservoir using the results of reservoir simulation to plan horizontal wells. One of the step out horizontal wells was very successful and opened new reserves for the field. Waterflooding is being considered for improved recovery.
  • Middle Bakken - Richland County, Montana - Production from micro-fractures in this mixed limestone and dolomite reservoir is accomplished using multi-lateral horizontal wells. IRT is currently conducting a fully integrated study of this developing oil field for one of the principal operators. Reservoir simulation shows that oil is charged into the relatively tight formation from the overlying Bakken Shale. Hydraulic fracture analysis of horizontal completions is a key part of the study.
  • Ridgelawn Field, Montana - This field produces from the Red River formation, which is a micro-fractured dolomite. Both laminated and burrowed facies are present in the dolomite layers with the laminated zones being much tighter that the burrowed zones. IRT is conducting a fully integrated reservoir study on this volatile oil field with the evaluation of waterflooding versus gas cycling for improved recovery.

Columbia

  • El Segundo Field - Full integrated study of the Cimarrona fracture-dominated sandy limestone reservoir. The reservoir exists in a regional syncline with a local anticinal development. In these studies, the complex structural geology of the field was defined through the detailed interpretation of 2-D and 3D seismic with statistical curvature analysis of dip meter data. All cores in the field were described in detail and were integrated into the reservoir description. Stratigraphic analysis identified nine separate facies within the productive reservoir horizon. Extensive petrophysical data, including FMI logs and over 300 thin section analyses were integrated with engineering data to show that the highly productive reservoir likely consisted of fractures only with no effective matrix porosity.
  • Guaduas Field -Detailed 3D seismic interpretation and fault/fracture analysis to associate production rates with fracture density. Utilize seismic attributes to identify stratigraphic limits to reservoir. Integrated satellite imagery with surface outcrop data to seismic structure. Correlate dipmeter data with bulk rock curvature to aid in development of structure where seismic image was inadequate. Use simulation model to estimate and quantify the original in-place and recoverable hydrocarbon volumes for the Cimarrona reservoir. Establish the most likely production potential of the wells compared with actual field productivity. Generate specific recommendations for pressure maintenance and maximization of recovery factor for the field. Perform rough economic evaluations for the production scenarios considered above determining the most appropriate exploitation plan. Prepare a development plan for the field. Provide a reliable updated numerical model of the reservoir for use in ongoing evaluations and reservoir management.

Historical Work by IRT Staff members

Kuwait

  • Maddud Reservoir Study, Raudhatain and Sabiriyah Fields, Kuwait (Simulation Engineer, 1993-1995)

Oman

  • Yibal Field, Oman - Geological and reservoir simulation study

Algeria

  • Rhourde Nouss Field, Algeria - Geological and reservoir simulation study to design gas cycling scheme.

Libya

  • Gialo, Libya - Integrated reservoir study of a fractured carbonate that resulted in reservoir simulation of infill drilling versus EOR alternatives.
  • Sarir Field, Libya - Integrated reservoir study of a giant reservoir resulting in infill drilling, step out development, and waterflood opportunities.

Iraq

  • Kirkuk, Iraq - Reservoir study involving reservoir description, reservoir engineering and simulation of complex fractured dual porosity reservoir.

Australia

  • Big Lake - Coopers Basin - Investigation of seismic techniques for fracture reservoir detection using geomechanical modeling.

Mexico

  • Abkatun / Pol / Chuc Fields - Integrated study of a large, naturally fractured oil complex encompassing three fields. In addition to developing detailed structural, stratigraphic, and diagenetic models we also developed a discrete fracture network to characterize fractures. The work included the processing, calibrating to core and MSFL logs, and interpreting FMS and FMI logs to determine fracture orientation, size, and intensity. Using this information at the well, developed an equivalent fracture network that included Sigma, fracture porosity, permeability, and continuity that was calibrated to well tests. The final fracture model was based on the assumption that faults mapped on seismic, subseismic faults, and fractures are part of the same population. Developed relationships between fractures and lithology, bed thickness and structure that were used to constrain the fracture model.
  • Sumaria / Iride Fields, Integrated Study of fractured carbonate reservoirs. Fracture parameter distribution was based on first and second derivative structure top mapping - with fault throws included - and calibrated with well tests. Structural model, reservoir description and fracture system characterization validated via history match. Used model to investigate miscible injection and artificial lift optimization.

North Sea 

  • Built petrophysical models and provided analysis for exploration plays targeting North Sea deep marine chalks, argillaceous chalks, and chalky marlstones of the Danian and Maastrichtian Ekofisk, Tor, and Hod Formations and the Permian age evaporite/carbonate reefs of the Zechstein Group, 2H-2005. Provided operational support for open hole and cased hole logging and well intervention activities of fractured Tor development wells in the Central North Sea.

Canada

  • Worked the Mississippian through Triassic Carbonate section of the foothills of the Western Canadian Sedimentary Basin. Targeted reservoirs were thrusted and fractured. Specialized in integrating well, including dipmeter, and seismic to develop the structural framework for planning infill well and new field wildcat targets. Well paths were optimized to maximize exposure of completions to open fractures. Structural models were built in Midland Valley's 2D and 3D move software for inclusion into Roxar's RMS geocellular modeling software.

Developed seismic parameters, QC'd of 3D seismic acquisition, processed and interpreted pinnacle reef fields in the Rainbow Lake area, Alberta for immiscible flood projects to recover residual oil. Development of seismic attributes to enhance gas/oil contact to aid in positioning wells near the oil meniscus near steeply dipping pinnacle edges. Paper of attribute analysis presented at CSEG conference.

United States

IRT staff have been involved in over 75 CO2 carbonate reservoir miscible flood projects in Texas, Colorado, Wyoming and California. Please contact us for further details.


Bakken Shale - North Dakota - Comprehensive, multi-client study of all reservoir engineering aspects of horizontal well placement, drilling and performance in fractured shale reservoir.