Abstract:

In view of the problem that the experimental data can’t be directly used in reservoir engineering calculation due to the large amount of stock tank oil loss in the process of multiple degasification of volatile oil, this paper proposes a new method to correct the experimental data of multiple degasification by means of constant-volume depletion experimental data step by step. The new method is different from the traditional method presented by Terry and Rogers（2017）that the experimental data of single degasification are used to correct the experimental data of multiple degasification. The comparison of the two methods shows that the traditional correction method is only suitable for conventional black oil, and may produce the non-physical correction results for volatile oil. The new method considers the variation of oil content in oil tanks with pressure in the exhaust gas under the standard condition, so it is applicable to both conventional black oil and volatile oil, and the correction result of the new method is close to that from the traditional Terry and Rogers method under the condition of saturated pressure. Finally, a simple iterative method is established based on the principles of material balance and oil & gas two-phase percolation, and the influences of various experimental data on development performance are calculated and compared. The results indicate that the typical black oil experimental data can be directly used for reservoir engineering calculation; the stronger the oil volatility is, the higher the recovery factor calculated from the new method will be; for the high volatility oil in the case, the error of the crude oil recovery percent of reserves calculated from the experimental data obtained with the traditional method is as high as -13.82% when compared with the new method.

Key words: volatile reservoir, multiple degasification, oil physical property, correction method, adaptability, dynamic prediction, error analysis