Method of determining oil reservoir exploitation level

Abstract

The invention relates to a method of determining an oil reservoir exploitation level based on through casing logging and relevant data on an open hole well. The method comprises: obtaining logging data in the through casing resistivity logging method and calculating the oil reservoir exploitation index. When the water salinity of the formation does not change, the exploitation index more than 0.7indicates intensive exploitation and the exploitation index less than 0.2 indicates non exploitation. When the water salinity of the formation changes, the oil saturation of the open hole well, the oil saturation of the cased well and the exploitation index are calculated in sequence at first; when the water production rate is higher than 0.8 during the water filling exploitation, the exploitation index more than 0.7 indicates intensive exploitation; and when the water production rate is lower than 0.1, the exploitation index less than 0.2 indicates non exploitation. The invention realizes the high investigation depth through casing resistivity logging, avoids the unobvious response of the radioactivity logging on the oil reservoir away from the casing and the requirements for the water salinity and the porosity of the formation, and improves the capability of the logging data to determine the oil reservoir exploitation level.

Description

technical field [0001] The invention relates to oil development technology, and is a method for determining the degree of exploitation of oil layers by using through-casing logging and related open-hole well data. Background technique [0002] With the deepening of oilfield development, most oilfields have entered the middle and late stages of production. Monitoring oil and gas layers and evaluating the degree of oil and gas layer recovery are the key to oil layer management for oil companies to adjust development plans and optimize oil field production in a timely manner. Currently, methods for monitoring oil and gas layers include carbon-oxygen ratio and neutron lifetime logging in cased wells. But when the porosity of the rock is less than 15%, the C / O carbon-oxygen ratio logging cannot be measured; when the formation water salinity is less than 20PPK, the neutron capture cross section logging is also not applicable. The application of the through-casing resistivity logg...

AI Technical Summary

Problems solved by technology

At present, there are two existing methods for changing the degree of production of oil and gas reservoirs: one is to use the Archie formula to determine the oil saturation of oil and gas reservoirs in open holes under the condition of water injection, such as the document "Using Well Logging Data" in the "Exploration Technology" journal. The Archie formula proposed in Calculating Controlled Reserves of Heterogeneous Conglomerate Reservoirs to calculate oil saturation, this method does not consider the influence of mud in pores on oil saturation, and secondly, it cannot effectively monitor cased wells dynamically Changes in oil layer development and production

Another method is the proposed method of monitoring the change of water saturation. The disadvantage of this method is that it does not quantify the relationship between the change of oil content and the classification of the degree of oil recovery.

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