Abstract
A Steamflooding study has been doing to extract the bitumen and improve oil recovery in a heterogeneous light oil reservoir of South Rumaila oil field. It has been investigated also that Steamflooding is an effective way to handle the formation’s heterogeneity by decrease the degree of fluid spread and distortion. It has been considered the design of experiments methodology and streamlines-based simulation to study the most sensitive factors affecting the cumulative oil production response and also to determine the optimal future reservoir performance. This paper is an extension work of the papers (SPE 165345 & SPE 165935) to evaluate the Geomechanical deformation associated with the production processes through steamflooding and water injection scenarios. The reservoir under study is a sandstone formation in South Rumaila oil field located in Iraq. This field, with a 59-year production history, has 40 production wells and is surrounded by an infinite active edge water aquifer from the east and the west flanks. Because of some discontinuous series of bitumen at the east flank, the strength of east flank is much effective less than the west one. In this study, a comparative thermodynamic simulation study has been conducted to show the feasibility of Steamflooding to extract the bitumen and improve oil recovery and to determine the optimal future development scenario in addition to locally estimating the associated reservoir deformation due to steamflooding processes and the base case of water injection.
In this paper, the black oil & thermodynamic reservoir simulator have been used to evaluate the reservoir performance through the base case and steamflooding scenarios, respectively. Later, full factorial design and streamlines-based simulation have been conducted to figure out the most factors affecting the response (recovery factor) through Steamflooding with distinct levels. The factors are steam injection rate, quality, temperature, and number of steam injectors.
Finally, as the oil produced for long time, the pore pressure would decrease with increasing the effective stress leading to reservoir compaction and vertical surface subsidence. Therefore, the expedition in production due to IOR/EOR methods should enhance the reservoir subsidence leading to serious problems in surface facilities setting. Therefore, the two models have been adopted to estimate the reservoir subsidence through steamflooding and base case, respectively.
By the end of 1 Feb. 2022, the results demonstrated that reservoir subsidence at the base case without steamflooding reached to approximately 10 ft as average at the crest of the reservoir. However, the reservoir subsidence after considering the steamflooding to the same date is more than 12 ft at the reservoir crest. However, The current subsidence for this reservoir in the current time after 59 years of predict is approximately two ft. at the crest.
