Probabilistic Analysis by Applying Uncertainty Worflows: A Case Study of the Teak Field, East Coast Trinidad

Segnini, Carlos; Rashwan, M.; Hernandez, M..; Rojas, Jose Alberto; Infante, Mariella Alexandra

doi:10.2118/169924-ms

Cited by 4 publications

(3 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Experimental Design (ED) has been used in diverse areas such as aerospace, civil engineering and electronics for analysis and optimization of complex, nonlinear systems described by computer models (Parikh, 2003). Experimental designs have also been used in petroleum engineering studies (Awoleke et al, 2012;Segnini et al, 2014; Ambastha 2014; Yu and Sepehrnoori 2014).…”

Section: Post-treatment Evaluationmentioning

confidence: 99%

Using experimental design and response surface methodology to model induced fracture geometry in Shublik shale

Poludasu

2016

Journal of Unconventional Oil and Gas Resources

View full text Add to dashboard Cite

The Triassic Shublik Formation of the Alaska North Slope is a world-class resource rock and has been identified as the major source of many of the conventional hydrocarbon accumulations on the North Slope, including Prudhoe Bay. Recent interest in the Shublik as a potential shale resource play has highlighted the need for robust hydraulic fracture modeling and simulation of the interval, but little geologic information is available because of the remote nature of the region and the complex character of the Shublik. In this study, a methodology was developed for identifying the critical variables needed for accurate planning of a hydraulic fracturing treatment in a play like the Shublik where much of the geology remains unconstrained. These identified critical variables can be used to develop a proxy model that can be used in lieu of a numerical simulator.This study was conducted in two stages. The first stage used 2-level fractional factorial design to identify the statistical significance of the input variables on the simulated fracture geometry. This stage was conducted in three phases, each phase incorporating progressively more complex assumptions about geology. Using the three most significant variables identified from first stage, the second stage of this study applies Box-Behnken experimental design and response surface methodology for quantifying functional relationships between input variables and the predicted fracture geometry. A pseudo 3D numerical simulator (Fracpro PT) and MATLAB were used to develop proxy models. These proxy models, typically a polynomial equation, are an easier alternative to Fracpro PT and can predict the fracture geometry with very less computational time.The use of experimental design drastically reduces the number of simulations required to evaluate large number of variables. With only 137 simulations, 26 variables were ranked based on their statistical significance and a non-linear proxy model was developed. Predicted values of the fracture geometry obtained using the proxy models were in good agreement with the simulated values of the fracture geometry (R 2 value of 99.39% for fracture length, R 2 value of 99.54% for fracture height and R 2 value of 98.17% for fracture width).

show abstract

Section: Post-treatment Evaluationmentioning

confidence: 99%

Using experimental design and response surface methodology to model induced fracture geometry in Shublik shale

Poludasu

2016

Journal of Unconventional Oil and Gas Resources

View full text Add to dashboard Cite

show abstract

“…Experimental designs have been widely used in petroleum engineering studies for inverse problems (Ouenes et al 1994), reserve estimation (Imrie and Macrae, 2014), uncertainity analysis (Segnini et al 2014;Ambastha, 2014), sensitivity analysis (Yu and Sepehrnoori, 2014), and proxy model development (Poludasu et al 2015).…”

Section: Figure 12-design Parameters Selected For Sensitivity Analysismentioning

confidence: 99%

Estimation of Optimal Frac Design Parameters for Asymmetric Hydraulic Fractures as a Result of Interacting Hydraulic and Natural Fractures - Application to the Eagle Ford

Paryani

Poludasu

Sia

et al. 2016

SPE Western Regional Meeting

View full text Add to dashboard Cite

Estimation of permeability in the Stimulated Reservoir Volume (SRV) is a vital input in any completion optimization workflow. One method to estimate the stimulated permeability in the SRV is to couple geomechanical modeling of the interaction between hydraulic and natural fractures with hydraulic fracture mechanics commonly used to design frac jobs. The proposed approach starts by deriving strain resulting from the integration of geological, geophysical and geomechanical modeling of interacting hydraulic and natural fractures. A unique feature of this approach is its ability to predict microseismicity, thus confirming the validity of the input natural fracture model and the geomechanical approach used to evaluate its interaction with the hydraulic fractures. The optimum validated geomechanical asymmetric half-lengths are then estimated from the derived strain map. These estimated geomechanical half lengths are used as a constraint in a frac design model which is able to incorporate this information and optimize stage treatments according to the variable SRV. The frac design parameters then need to be adjusted in order to approximately match the geomechanical half-lengths provided by the strain map.A new analytical asymmetric frac design model is developed, validated with existing commercial frac design software, and used in this study. The new asymmetric analytical frac design model is a pseudo 3D model that accounts for the variation in height in an iterative approach along with considering the asymmetric half lengths due to the lateral stress gradients in a heterogeneous reservoir. The new asymmetric analytical frac design model was compared to existing commercial frac design software and was found to provide similar estimations of frac heights but in a fraction of the time needed to run the commercial frac design software. The ability to combine these models and simultaneously solve for the optimum fracture height is provided by the constraints of the geomechanical half lengths derived from the strain map. In order to guide the engineer designing a frac job an optimum selection of the design parameters to get the target fracture geometry, this paper also presents a parametric analysis using experimental design of various fracing parameters used in our asymmetric hydraulic fracture model.In this study, the workflow was successfully applied to a complex Eagle Ford well. The frac design tool optimizes important parameters such as the injection rate, fluid viscosity, proppant type, proppant size, proppant specific gravity and leak-off coefficient in order to honor the interaction of natural and hydraulic fractures accounted for in geomechanics. The frac design model also provides vital information such as the proppant schedule to be pumped and the variation of propped length, width, and net pressure as a function of time. The results of this workflow are the fracture conductivity and proppant concentration along the fracture length and their interpolation between the stages so they can be exported to any reservoir...

show abstract

“…A large number of proxy simulations are run to obtain an approximation to the true statistical distribution. Finally, the cases corresponding to P10, P50 and P90 on that distribution are selected out of the run cases 3 .…”

Section: Probabilistic Forecastingmentioning

confidence: 99%

From Screening to Drilling – Planning a Drilling Campaign in an Offshore Mature Field: A Case Study of TSP Field, East Coast Trinidad

Hernandez

Segnini

Grimaldi

et al. 2014

SPE Energy Resources Conference

View full text Add to dashboard Cite

Repsol (operator), together with partners Petrotrin and National Gas Company of Trinidad and Tobago, took over operations of mature fields Teak, Samaan and Poui (TSP) Offshore Trinidad at the end of 2005. With the intention of planning further development in the TSP reservoirs (comprising more than 10 vertically stacked main units, highly compartmentalized reservoirs with complex tectonic geometries) an indigenous comprehensive field evaluation was required. Thus, a sand-by-sand Screening Project was carried out with the main objective of identifying the reservoirs with maximum potential so as to direct further technical effort on specific reservoirs for early monetization of reserves.Based on the results of the sand-by-sand screening project, a prospect validation project for Teak Field was initiated -consisting of extensive field data acquisition, detailed interpretation and modeling workflows, adapted to the particular needs of mature fields. Several incremental opportunities identified during screening were validated and detailed modeling was performed to support further development. On completion of this effort, the company acquired a holistic view of the asset in terms of projects and its remaining resources, so a drilling campaign was envisioned and planning started.The selection of drilling candidates was not a straight forward process. The number of opportunities had been reduced considerably from the opportunity category to the actual well candidates. Several disciplines developed specific workflows to overcome the challenges, for example: risk assessment for infill opportunities and probabilistic forecasting (Subsurface), trajectory designs including anti-collision, drilling through depleted sands, torque and drag analysis and selecting a suitable rig for the field and production platform conditions (Drilling Engineering); among others.At the time of submitting this paper, two drilling rigs are moving onto the acreage to start drilling these opportunities by the end of 2013. This paper outlines the different challenges faced, as well as case studies of the evolution and maturation from the screening to the drilling stage of some of the prospects.

show abstract

Probabilistic Analysis by Applying Uncertainty Worflows: A Case Study of the Teak Field, East Coast Trinidad

Cited by 4 publications

References 4 publications

Using experimental design and response surface methodology to model induced fracture geometry in Shublik shale

Using experimental design and response surface methodology to model induced fracture geometry in Shublik shale

Estimation of Optimal Frac Design Parameters for Asymmetric Hydraulic Fractures as a Result of Interacting Hydraulic and Natural Fractures - Application to the Eagle Ford

From Screening to Drilling – Planning a Drilling Campaign in an Offshore Mature Field: A Case Study of TSP Field, East Coast Trinidad

Contact Info

Product

Resources

About