Method for calculating wellbore water-holding capacity and formation water saturation in RPM well logging

Abstract

The invention relates to a method for calculating wellbore water-holding capacity and formation water saturation in RPM well logging. The method comprises the steps that a regular chart of the changes of the carbon-oxygen ratio along with formation porosity in RPM well logging is obtained only considering the sizes of a wellbore and a casing pipe; a carbon-oxygen ratio calculation formula is obtained according to the sizes of the wellbore and the casing pipe in RPM well logging; the carbon-oxygen ratio in RPM well logging is obtained when water filling is conducted on a wellbore water filling formation and oil filling is conducted on a wellbore water filling formation; the carbon-oxygen ratio in RPM well logging is obtained when oil filling is conducted on a wellbore oil filling formation and water filling is conducted on a wellbore oil filling formation; carbon density and oxygen density of water in the wellbore and carbon density and oxygen density of oil in the wellbore are calculated; the carbon-oxygen ratio in RPM well logging is calculated when influence factors comprise the wellbore, the casing pipe and gravel; the carbon-oxygen ratio in RPM well logging is calculated when the influence factors comprise the wellbore, the casing pipe, the gravel and mud; the carbon-oxygen ratio in RPM well logging is calculated when influence factors comprise the wellbore, the casing pipe, the gravel, the mud and calcium; a cross plot of near-far carbon-oxygen ratio is built; the wellbore water-holding capacity and the formation water saturation are obtained according to the cross plot of the near-far carbon-oxygen ratio.

Description

technical field [0001] The invention relates to the field of petroleum exploration and development, in particular to a method for calculating wellbore water holdup and formation water saturation in RPM logging. Background technique [0002] RPM (Reservoir Performance Monitor) is a multifunctional pulse neutron logging tool produced by Atlas Company. This tool was introduced in China in 2001 and has been used in 115 wells in Bohai, Shanghai, Zhanjiang and other offshore oil and gas fields. The measurement has effectively solved many problems faced by various oilfields, such as remaining oil, oil-water interface, water-flooded layer, fluid properties of low-resistivity oil and gas layers, and determination of water-flooded direction. At present, Wu Wensheng from China University of Petroleum (Beijing) has used the Monte Carlo numerical simulation method to correct the influencing factors of the carbon-oxygen ratio logging in the RPM instrument logging with small diameter and d...

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Problems solved by technology

Both of them established correlation charts for simulating PNN logging under different influencing factors, but...

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