Gazprom Neft has set an ambitious strategic goal: reach up a production plateau at 100 million TOE per year. To achieve this goal, the company will need to increase the resource base, develop and commission new fields, and work with the basic production at the existing assets.

As of today, 95% of the company's fields are produced with a reservoir pressure maintenance (RPM) system. The reservoir pressure maintenance system is the key to ensuring sustainable production of an oil field. Condition and operation of this system have immediate effect on the reservoir behavior, displacement parameters, and, therefore, oil production profile. However, almost all of Gazprom Neft's subsidiaries are facing the problem of analyzing and interpreting field performance data because the process is too long and complex while its results are not obvious and unambiguous. For this reason, it may not always be clear in what part of the system there is a problem: the reservoir, the well or the infrastructure.

Let us turn to the widely known formula used to determine the oil recovery factor (ORF) (1):
(1)

where Ksweep is the sweep efficiency (factor), and

Kdispl. is the displacement efficiency (factor).

Ksweep is the ratio of the volume of the reservoir being drained by the wells to the total volume of the reservoir. The sweep efficiency characterizes the effect of reservoir discontinuity (alternation of permeable and impermeable bodies) on the filtration parameters, i.e. how the drained volume of the reservoir is reduced compared to the case when the reservoir does not contain any impermeable bodies in it.

The main task when developing the reservoir then is to ensure full involvement of its entire volume in the process of drainage. But with a high degree of heterogeneity or a significant difference in mobility of oil and the displacing agent, flooding efficiency decreases which is expressed in lower sweep efficiency too. The main reason for that is the uneven propagation of the injected water front over the area and cross-section of the reservoir.

Kdispl. is the ratio of the volume of oil displaced by water from a reservoir rock sample or reservoir model till 100% water cut to the initial volume of oil contained in the rock sample or reservoir model.

Keywords:
enhanced recovery, modeling, Efficiency, sugmutskoe group, compensation, waterflooding, pressure maintenance system, well pad, formation pressure, linear pressure
Subjects:
Reservoir Characterization, Improved and Enhanced Recovery, Formation Evaluation & Management, Waterflooding, Conformance improvement
Copyright 2018, Society of Petroleum Engineers
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