Simple method for determining organic porosity of shale gas reservoir

Abstract

The invention relates to a simple method for determining the organic porosity of a shale gas reservoir. The method includes the steps that volume density Rhob data and the total organic carbon contentTOC data of the shale gas reservoir of a well are acquired; the organic porosity scale conversion coefficient K is determined; according to the volume density Rhob bdata of the shale gas reservoir, the total organic carbon content TOC data and the organic porosity scale conversion coefficient K, the organic porosity PORtoc of the shale gas reservoir of the well is calculated according to the formula of PORtoc=K (TOC / Rhob), and a calculation result is output. The method is simple and easy to implement, wide in adaptation range and low in cost. The method is applied to over 80 wells in a Mausoleum shale gas field, the result obtained through the method is close to those obtained through other methods, the average error is not larger than 10%, the method can meet the work requirement for quickly evaluating the shale gas reservoir on the site, and important reference is provided for shale gas exploration area selection and reserve evaluation.

Description

technical field [0001] The application field of the invention is shale gas exploration and development, and specifically relates to a simple method for determining the organic porosity of shale gas reservoirs, which provides key parameters for rapid on-site evaluation of shale gas reservoirs. Background technique [0002] In the fine interpretation and evaluation of shale gas reservoirs, the porosity of shale gas reservoirs is usually divided into inorganic porosity and organic porosity. The organic porosity of shale gas reservoirs is an important index to evaluate the quality of shale, and plays a key role in the evaluation of physical properties, gas content and gas production of shale gas reservoirs. [0003] Through retrieval of relevant literature and patents, we learned that the determination of the organic porosity of shale gas reservoirs mainly depends on the core laboratory analysis of special equipment, and the method for determining the organic porosity of shale g...

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Problems solved by technology

[0003] Through retrieval of relevant literature and patents, we learned that the determination of the organic porosity of shale gas reservoirs mainly depends on the core laboratory analysis of special equipment, and the method for determining the organic porosity of shale gas reservoirs based on well logging data is relatively It is complex, requires a large amount of information, requires high quality personnel, and is not suitable for quickly determining the organic porosity of shale gas reservoirs on site. Therefore, a fast, simple, accurate and reliable method is urgently needed. On-site Rapid Evaluation Provides Organic Porosity of Shale Gas Reservoirs

[0004] CN104794351A discloses a method and device for calculating the total organic porosity of shale gas reservoirs. The method is derived based on the relationship between mass-volume-density-organic matter content, and is used to solve the total organic porosity of shale gas reservoirs in the prior art. Porosity cannot be detected and obtained, and there is no standard calculation formula

The method provided by this invention can provide reliable data for the evaluation of shale gas reservoirs, but the calculation of Roa requires a lot of data, and the standardized processing of these data needs to be done well. It is relatively difficult to apply on the drilling site, and in the drilling process Unable to determine organic porosity of shale gas reservoir while drilling

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