页岩含气量计算及各因素敏感性分析

发布时间：2018-02-17 00:02

本文关键词： 页岩含气量模型计算敏感性吸附相体积　出处：《太原理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：页岩气是典型的非常规油气藏,其保存条件、成藏机理、及储层特征等与常规油气藏的存在较大差异,因此页岩含气量的评估己经不能用常规油气藏的储量计算方法。基于页岩气的典型特征,探索适用于页岩含气量的计算方法,可对我国页岩气储量的评估与计算、判断气藏是否具备商业开发价值提供依据。本文在前人的研究基础上,开展影响页岩含气量的主控因素和计算方法的研究,主要研究内容与结果包括以下几点:(1)分析影响页岩含气量的因素主要有总有机碳含量(TOC)、干酪根成熟度(Ro值)、裂缝发育程度、孔隙结构、黏土矿物和脆性矿物的含量、温度、压力和湿度等。其中,TOC含量为页岩吸附的核心要素,与吸附气量呈正相关。电阻率与孔隙度测井曲线重叠法、放射性铀元素与总有机碳关系回归法是常用的有机碳含量计算方法;Ro值代表页岩热演化程度,基本在一定范围内与页岩含气量呈正相关,通常采用镜质体反射率或镜状体反射率测量;孔隙决定页岩比表面积,可根据页岩岩石物理模型,将各种测井参数方程联立来求取孔隙度;含水量大于4%时,页岩的湿度越大,储集能力越差,采用Simandoux方程计算页岩的含水饱和度;温度对页岩的吸附能力起抑制作用,压力一定时,温度越高,吸附能力越差,解吸能力越强;压力对吸附能力起促进作用,温度一定时,压力越大,吸附能力越强。(2)采用间接法,分析影响页岩气吸附气量的主要因素有深度(H)、TOC、Ro。其中H反应温度与压力的综合作用。将三种因素考虑在内,采用变差函数球状模型较准确地模拟了在地层条件下,伴随不同的TOC、Ro值,吸附气量的变化趋势。采用正交分析法,定量化研究不同影响因素的效应和敏感性。实际情况下,随深度增加,温度、压力同时增大,吸附气量随深度的变化存在转折点,在转折点以浅压力对吸附气量的敏感性大于温度;在转折点以深,温度对吸附气量的敏感性大于压力。本文可评估在不同H、TOC、Ro条件下,页岩气藏的含气量。方法较为简便,可解决气藏储量的评估预测和有利区优选等问题。(3)基于游离气计算的通用方法,由于孔隙直径与甲烷气体分子直径处于同一个数量级,故吸附相体积在总孔隙体积中所占比例不可忽略,故总孔隙体积应减去吸附相体积,以修正游离气量。
[Abstract]:Shale gas is a typical unconventional oil and gas reservoir. Its preservation conditions, reservoir forming mechanism and reservoir characteristics are quite different from those of conventional oil and gas reservoirs. Therefore, the evaluation of shale gas content can not be calculated by conventional oil and gas reservoir reserves. Based on the typical characteristics of shale gas, this paper explores the calculation method suitable for shale gas content, which can be used to evaluate and calculate the shale gas reserves in China. Judging whether the gas reservoir has commercial development value provides the basis. Based on the previous studies, this paper studies the main control factors and calculation methods that affect shale gas content. The main research contents and results are as follows: analysis of the factors affecting shale gas content: total organic carbon content (TOC), kerogen maturity (Ro), fracture development, pore structure, clay mineral and brittle mineral content, temperature. The content of TOC is the core element of shale adsorption, which is positively related to the amount of gas adsorbed. The regression method of the relationship between radioactive uranium element and total organic carbon (TOC) is a commonly used method for calculating the content of organic carbon. The Ro value represents the degree of thermal evolution of shale, and basically has a positive correlation with the gas content of shale within a certain range. Usually measured by vitrinite reflectance or vitrinite reflectance; porosity determines the specific surface area of shale, according to shale rock physical model, various logging parameter equations can be combined to obtain porosity; when water content is greater than 4, the moisture content of shale increases. Simandoux equation is used to calculate the water saturation of shale, and temperature inhibits the adsorption capacity of shale. The higher the pressure is, the worse the adsorption capacity is, the stronger the desorption ability is, the higher the pressure is, the stronger the desorption capacity is. When the temperature is constant, the adsorption capacity is stronger with the pressure increasing. (2) the indirect method is used to analyze the main factors affecting the adsorption capacity of shale gas. The main factors affecting the adsorption capacity of shale gas are the depth of H reaction temperature and the pressure. The three factors are taken into account. Variation function spherical model is used to simulate the variation trend of adsorbed gas quantity with different TOC Ro values. The effects and sensitivities of different influencing factors are quantitatively studied by orthogonal analysis. With the increase of depth, the temperature and pressure increase simultaneously, and there is a turning point in the variation of adsorption gas quantity with depth. At the turning point, the sensitivity of shallow pressure to adsorption gas quantity is greater than that of temperature, and at the turning point, the depth of adsorbed gas quantity increases. The sensitivity of temperature to adsorption gas volume is greater than that of pressure. This paper can estimate the gas content of shale gas reservoir under different Hetoco Ro conditions. The method is simple and convenient. The general method based on free gas calculation can solve the problems of reservoir reserve evaluation, prediction and favorable area selection. Because the pore diameter is in the same order of magnitude as the diameter of methane gas molecule, the pore diameter is in the same order of magnitude as the methane molecule diameter. Therefore, the proportion of the adsorption phase volume in the total pore volume should not be ignored, so the total pore volume should be subtracted from the adsorption phase volume to modify the free gas volume.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.13

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