A geological evaluation method for fracture network stimulation ability of marine shale gas reservoirs

Abstract

The invention discloses a geological evaluation method for the fracture network reconstruction ability of a marine shale gas reservoir, comprising the following steps: collecting geological data of the marine shale gas reservoir; establishing a geological evaluation method for the fracture network reconstruction ability of the reservoir Index sequence, the geological evaluation index sequence includes mineral ductility resistance index, rock elastic-plastic index, fracture network index, and reservoir physical property index; calculate the weight of the geological evaluation index for the fracture network reconstruction ability of the reservoir; establish the fracture network A geological evaluation matrix of the stimulation capability, the larger the geological evaluation matrix result is, the more favorable the stimulation of the reservoir fracture network is. The present invention achieves that the characterization parameters among the influencing factors do not affect each other and do not conflict, saves data sorting and calculation time, and at the same time ensures the accuracy of evaluation, is easy to use in the actual application process, and is suitable for indoor scientific research personnel and on-site technology Personnel provide quick results, simplify complexity, and help optimize frac parameters.

Description

technical field [0001] The invention relates to the technical field of unconventional oil and gas stimulation technology, in particular to a geological evaluation method for the fracture network stimulation ability of marine shale gas reservoirs. Background technique [0002] Reservoir evaluation is an important link in the process of shale gas exploration and development, and it is mainly used to optimize the target window sweet spot. The evaluation indicators of shale gas reservoirs are diversified, including differential structure of mineral components, development characteristics of natural weak planes, mechanical properties of rocks and fractures, ancient and modern burial depths, thermal evolution degree and organic matter abundance, porosity and Geological factors such as pore shape, magnitude and difference of in-situ stress. The conceptual evaluation of shale gas production areas can be realized by superposition of brittle mineral content; the three-dimensional des...

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Problems solved by technology

However, it can be seen from different methods that scholars have different understandings of reservoir evaluation, which also makes the existing evaluation theories and methods still have room for improvement, which is reflected in: ① Invention of CN201610191202.8, CN201510094413.5, CN201410641815.8 For example, the evaluation ideas are not uniform, multi-factor evaluation indicators are complicated, and the interaction between the indicators is not considered. For example, the increase of siliceous mineral content does not completely increase the brittleness, and the increase of porosity and organic matter content increases the storage capacity. , but reduces the mechanical strength of the rock, etc. Too many natural fractures will affect the difficulty of adding sand, etc., resulting in different opinions and conclusions in different evaluation results; ② Some evaluations believe that construction parameters are evaluation indicators, but evaluation indicators are not Engineering parameters, but geological parameters that reflect the adaptability of engineering parameters, currently rarely include geological evaluation indicators that reflect the adaptability of reservoirs to construction parameters; ③ It is not clear whether the final evaluation goal is effective fracturing or stimulation; ④ Invention CN201910688867. 3 as an example, the calculation steps are too complicated, and it is difficult to quickly identify and optimize in mine practice; ⑤Taking the inventions CN201610537793.X and CN110163533A as examples, both failed to consider the weights between various factors, even if the weights are considered, only the influence of each factor is considered the degree is equal

[0003] The southern Sichuan region is the main area for shale gas development in my country. As the gas-producing zone transitions from 2500-3000m to 3000-3500m in the construction-production area, hydraulic fracturing is faced with increased closure stress and horizontal stress differences. Natural fractures and bedding The characteristics of increasing difficulty in characterization, and the average annual single well production has decreased in recent years, indicating that the existing evaluation methods are no longer suitable for geological characteristics and actual needs

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