Drilling fluid density determination method and static equivalent density determination method

Abstract

The invention discloses a method for determining drilling fluid density, and a method for determining equivalent static density. The method for determining the drilling fluid density in a shaft comprises the following steps that: S1: obtaining initial drilling fluid density [Rho]0, drilling fluid component parameters and the vertical depth data and the temperature data of each analysis point, and carrying out normalization on the initial drilling fluid density [Rho]0 and component data to obtain a first normalization dataset; S2: according to drilling fluid density [Rho]i, pressure Pi and the vertical depth data of an ith analysis point and an (i+1)th analysis point, calculating pressure Pi+1; S3: according to the pressure Pi+1 and temperature data Ti+1, calculating a pressure difference [Delta]Pi+1 and a temperature difference [Delta]Ti+1; S4: carrying out normalization processing on the pressure difference [Delta]Pi+1 and the temperature difference [Delta]Ti+1, and combining with the first normalization dataset to obtain a second normalization dataset; and S5: according to the second normalization dataset, utilizing a preset neural network model to obtain the drilling fluid density [Rho]i+1 of the (i+1)th analysis point. By use of the method, a great quantity of repeated experiments and data analysis can be avoided, and the calculation accuracy and efficiency of the high-temperature high-pressure well shaft ESD (Equivalent Static Density) can be greatly improved.

Description

technical field [0001] The invention relates to the technical field of oil and gas exploration and development, in particular to a method for determining the density of drilling fluid and a method for determining the static equivalent density. Background technique [0002] As my country's oil and gas exploration and development gradually enter deep formations, the development of high-temperature and high-pressure deep wells and ultra-deep wells continues to increase, which also leads to widespread drilling problems with narrow safe density windows. , referred to as ESD) is the basis for accurately calculating the bottom hole pressure and ensuring safe drilling. [0003] One of the foundations for accurate calculation of wellbore ESD in high temperature and high pressure wells is to accurately predict the density of drilling fluid under high temperature and high pressure. Many scholars at home and abroad have carried out corresponding research on the variation of drilling flu...

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Problems solved by technology

[0007] However, as the drilling fluid system used in actual drilling engineering becomes more and more complex, it is difficult to use an empirical model based on a certain drilling fluid system to predict the drilling fluid density of all drilling fluids under high temperature and high pressure, which also affects the The calculation accuracy of wellbore ESD, so the existing method can no longer meet the needs of safe drilling

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