A Prediction Method of Caprock Sealing Performance in Ordos Basin

Abstract

The invention belongs to the technical field of petroleum exploitation, and relates to how to quantitatively estimate covering layer sealing performance in processes of carrying out a CCUS project. Acovering layer sealing performance prediction method of the Ordos basin is provided and comprises steps of selecting a production well of a to-be-estimated region, and reading the starting depth valueX1 and the thickness of a long 4+5 covering layer on a well logging curve; carrying out segmentation and fitting the interval transit time curve of the long 4+5 covering layer, and calculating the interval transit time value corresponding to the interval transit time curve; and substituting the read thickness value h and the corresponding interval transit time of the long 4+5 covering layer intoa formula, calculating a composite displacement pressure value P and evaluating the sealing performance of the covering layer by use of the P. According to the invention, the prediction method is simple and convenient; it can be avoided that a plenty of time and cost are used for obtaining horizontal displacement pressure and vertical displacement pressure through a high-pressure mercury intrusionmethod or a breakthrough pressure method; and inaccuracy caused by that fact the horizontal displacement pressure measured by the high-pressure mercury intrusion method or the vertical displacement pressure measured by the breakthrough pressure method is used as an index to measure the sealing performance of the covering layer can be avoided.

Description

technical field [0001] The invention belongs to the technical field of petroleum exploitation, and relates to how to quantitatively evaluate the caprock sealing performance in the development process of CCUS projects. Background technique [0002] Before launching a CCUS project, evaluating the sealing performance of the caprock is the key to ensure that the CO 2 Necessary link for safe storage. At present, the commonly used caprock sealing performance evaluation methods mostly use the displacement pressure of the caprock as the index, and it is believed that the higher the displacement pressure, the better the sealing performance of the caprock, and the displacement pressure value is mostly measured by the high-pressure mercury intrusion method or the breakthrough pressure method . [0003] However, it is obviously unscientific to measure the sealing performance of the caprock only by the expulsion pressure and ignore the influence of the caprock thickness. In addition, ...

AI Technical Summary

Problems solved by technology

[0005] In addition, taking the first group of test results as an example, if the horizontal displacement pressure measured by mercury porosimetry is used as the evaluation index, there is P xA >P xB >P xD >P xC , indicating that the order of sealing performance of the four well caprocks from good to poor is Well A, Well B, Well D, and Well C; if the vertical displacement pressure measured by the breakthrough pressure method is used as an index, there is P yB >P yC >P yA >P yD , indicating that the sealing performance of the four wells in order from good to poor is Well B, Well C, Well A, and Well D. x or P y The method of evaluating regional cap rock sealing for a single evaluation index is not accurate

[0006] In addition, experimenting to obtain multiple horizontal and vertical displacement pressures is time consuming and expensive

Images