Integration of Subsurface, Surface and Economics Under Uncertainty in Orocual Field

Abstract

fax 01-972-952-9435. AbstractOrocual field is one of the largest growing onshore opportunities in North of Monagas basin, eastern Venezuela. The field is planning to increase its production potential to more than 500% in the next five years. Business plan involve new expansion opportunities with improving field economics. These opportunities include massive development of the shallow heavy oil horizons by steam injection and development drilling in the deeper light and condensate reservoirs. To accomplish such a challenging goal, it was necessary to estimate new requirements for surface facilities while considering both reservoir uncertainties and multiple development scenarios. This paper presents a unique and innovated method and a case-study for integrating multiple-reservoir forecasts with a surface facilities network, with economics and uncertainty. Subsurface responses from five Orocual formations were obtained from ten different reservoir simulation models with their associated well constraints. One single surface network model was used to gather production information from all the reservoirs and likewise was used to develop alternate production scenarios. An automated workflow handled the integration of reservoir production uncertainty, drilling schedule compliance, workover success, economics and varying surface facilities capacities.The procedure that we have developed in this effort permitted the visualization of a more realistic asset performance compared to requirements in the long-term. The procedure also identified future needs for artificial lift.The methodology developed also served as a platform for the exhaustive optimization of wellbore and surface equipment sizing in the presence of uncertainties based on front-endloading (FEL) methodology. The procedure allowed the evaluation of parameters that affect uncertainty in well productivity, drilling schedule compliance, workover success, and varying surface facilities capacities, such as project execution time, workover success, facilities uptime, and facilities spare capacity. SPE 107259uncertainty, drilling schedule compliance, workover success, and varying surface facilities capacities.In general, the automated workflow, developed in this effort, permitted the visualization of a more realistic asset performance in the long-term identification of future requirements for artificial lift. The methodology developed also serves as a platform for the exhaustive optimization of wellbore and surface equipment sizing in the presence of uncertainties.

Integrated Economic Model for Evaluation and Optimization of Cyclic-Steam-Stimulation Projects

“…The FISAM developed in this study differs from other models in that it contains a subsurface model which can use either a CSS decline model or an analytical model that was developed specifically for horizontal CSS by Saripalli (2013). In addition, the subsurface model is connected to a surface model and an economic model by use of a FISAM framework developed specifically for the optimization of a thermal heavy-oil project.…”

“…The analytical model used in this paper was derived from the model developed by Saripalli (2013). This model uses a radialheat-transfer model that was developed to predict the average temperature in the steam zone.…”

“…The main assumptions of the Saripalli (2013) model are that the well is placed at the center of the formation, the reservoir is initially saturated with oil and water, the steam forms a cylindrical steam chamber, the steam is injected at a constant temperature, and heat is transferred from the heated zone to the adjacent reservoir through conduction. In addition, the model assumes that the temperature distribution is an idealized step function, the main driving force for fluid production is pressure drawdown, and that flow is through the heated area.…”