Calculation method capable of accurately obtaining shale gas loss

Abstract

The invention discloses a calculation method capable of accurately obtaining shale gas loss amount. The method comprises the following steps: a brand-new shale gas loss amount calculation formula is established based on a double-first-order kinetic model: qd(t)=qt[1-[q1exp(- K1t)+q2exp(-K2t)]]- ql, a shale core sample of shale gas drilling is subjected to an on-site desorption experiment on a drilling site; collecting desorbed gas quantity data at the same time interval; and then drawing a shale gas desorption curve, fitting the shale gas desorption curve by utilizing the shale gas loss amountcalculation formula, and obtaining the shale gas loss amount ql of the shale core sample and the specific numerical values of the immeasurable outline constants q1, q2, k1 and k2 according to a regression equation. The method has the advantages that a diffusion model, namely a double-first-order kinetic model, more suitable for shale gas serves as a theoretical basis, the shale gas loss amount calculation method is established, the fitting effect and precision are improved, and the problem that in the past, the shale gas loss amount calculation effect is poor is well solved.

Description

technical field [0001] The invention relates to a calculation method of gas loss, in particular to a calculation method capable of accurately obtaining shale gas loss, and belongs to the technical field of gas content measurement of unconventional natural gas. Background technique [0002] With the continuous development of unconventional oil and gas fields, shale gas has become a global energy hotspot. The gas content of shale is the direct expression of the existence of shale gas resources and whether it has economic development value. Therefore, how to accurately obtain the gas content of shale has become the top priority of current shale gas research and exploration. [0003] At present, the methods for obtaining the gas content of shale gas mainly include indirect method and direct method. [0004] As the name implies, the indirect method is a method to obtain shale gas content through indirect means, mainly by adding the adsorbed gas amount and free gas amount obtain...

AI Technical Summary

Problems solved by technology

[0009] It can be seen that although USBM linear regression method, Amoco curve fitting method and Smith-Williams method have been used to obtain shale gas loss, there are still defects and inconveniences in terms of theoretical basis and calculation accuracy, especially in the loss of gas volume. Accurate acquisition requires targeted analysis and consideration

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