Insight of HASD Technology in an Extra Heavy Oil Field in Comparison to Traditional Thermal EOR Processes

The development of giant fields of extra-heavy crude oil (XHO), through the massive application of thermal EOR processes, involves investments of several millions of dollars. It is a technical challenge to evaluate, by means of numerical simulation, and in a reasonable period of time, the behavior of EOR processes in giant fields. This paper describes a semi-analytical methodology to evaluate thermal processes of EOR and to provide, in a suitable time, the input data required by the investment decision makers. The methodology follows 4 main steps. 1) The field is divided in sectors using a special defined EOR-Quality Index. 2) Six representative Model-sectors are selected in each reservoir and used to perform numerical simulations of all EOR processes to be evaluated in the field. 3) Extrapolation of simulation results to all the individual sectors of the field (Field-sectors), by using a defined extrapolation function. 4) Synchronization of injection and production profiles for each EOR technology, in each individual Field-sector following the field development plan. The methodology was successfully applied to a giant-XHO field, in the Orinoco Oil Belt, where primary production followed by combinations of different sequences of Cyclic Steam Stimulation (CSS), Steam Flooding, Steam Assisted Gravity Drainage and Horizontal Alternate Steam Drive were evaluated at fullfield scale. The proposed methodology allows analyzing many more production strategies without losing the vision of the global impact of EOR operations in the whole field. Two validation tests were performed to check the robustness of the method. The first test checked the extrapolation function. A set of random selected Field-sectors in which EOR recovery performances were evaluated through both numerical simulation, and also with the extrapolation function. Comparable results were obtained by both methods. A final validation test was done performing a fullfield simulation study for a CSS application. The simulation model had 23MM active blocks, about 1000 horizontal wells, thermal PVT formulation, and 40 years of production. Comparable results in terms of production potential and plateau duration were obtained, which validates the proposed methodology. The numerical fullfield test took around one week, and it was also expensive in resources. The presented semi-analytical methodology overcomes the challenges of expensive and long numerical simulations, by an innovative way to characterize the dynamic response of Model-sectors and to extrapolate it into the all Field-sectors. The methodology is flexible enough to consider different kind of EOR processes configuration sequences, as well as, the evaluation of the processes at different scales as: sector, reservoir units and fullfield.

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Surface Facilities for a Giant Thermal EOR Project - Cost and HSE Implications of Alternative Fuels for Steam Generation

Coll

Peña

Guitián

et al. 2017

Day 3 Wed, November 15, 2017

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This paper describes three different surface facility configurations for an Enhanced Oil Recovery (EOR) project in the Orinoco Oil Belt (OOB), where steam-based, thermal EOR processes are planned to be used at a very large scale. After an initial EOR screening process, four steam-based, thermal EOR technologies werepre-selected as potentially suitable options for the field: Cyclic Steam Stimulation (CSS), Steam Flooding (SF), Steam-Assisted Gravity Drainage (SAGD), and Horizontal Alternating Steam Drive (HASD). In the conceptualization phase, several alternative cases were consideredfor each technology, including variations in injection rates, deployment schedule, and well spacing. All these subsurface cases could be condensed into two design cases for the surface facilities: a low steam generation rate case, and a high steam generation case. However, due to the very large project size and the potential competition with other developments, uncertainty existed about the amount of natural gas that could be available as fuel for the steam generation, as well as about the environmental implications of the EOR operations. To handle these uncertainties, two alternative fuels were considered in addition to natural gas: coke and extra-heavy oil (XHO); a fourth option consisting in a combination of gas and coke was also included in the study. Surface facilities for the two steam generation rates and for the four different fuel alternatives were conceptualized obtaining class V cost estimates. Environmental impact in terms of CO2 emissions and fresh water demand was also evaluated for all the design cases. As expected, natural gas is the fuel that leads to lower cost facilities, as well as to a smaller environmental footprint. On the other hand, in the probable case that not enough gas is available, the decision to use coke or XHO as an alternative fuel will depend on the relative weight given to the economic and environmental factors, which are very related to the EOR technology selected for the field. Thus, this work demonstrates how the integration of the surface facility designs with the reservoir studies allows obtaining very useful insights on the advantages, risks and drawbacks of each EOR technology. This innovative subsurface-surface integrated approach sets the basis for high quality project decisions.

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Insight of HASD Technology in an Extra Heavy Oil Field in Comparison to Traditional Thermal EOR Processes

Cited by 3 publications

References 7 publications

Thermal Methods of Recovery

Thermal Methods of Recovery

Overcoming the Challenge of Forecasting EOR in Giant Extra-Heavy Oil Fields

Surface Facilities for a Giant Thermal EOR Project - Cost and HSE Implications of Alternative Fuels for Steam Generation

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