磨溪雷一¹气藏可采储量评价研究

Study on the Accurate Evaluation of Recoverable Reserves in Moxileiyi¹ Gas Reservoir

摘要: 磨溪雷一¹气藏储层非均质性强，总体具有中孔、特低渗的特征，各区块开采时储量动用程度、储层认识程度及先后有差异，给气藏各区块可采储量的准确评价带来了难度；若单一使用某种方法评价可采储量，往往误差较大，难以合理指导提采计划。首先利用目标层位井下岩心设计并开展了低渗、高渗、高低渗串联衰竭式开采模拟实验，以研究储层渗透率及配产对采收率的影响，并初步标定目标储层采收率范围；然后利用类比法，根据前人对不同气藏类型、废弃条件的研究成果，进一步对目标储层采收率进行细化；接着利用产量递减法，根据气藏不同区块正常生产井递减率统计结果，优化目标储层采收率；最后利用压降法，根据目标区块典型井实际关井数据获得最为合理的目标储层采收率，并合理预测各区块可采储量。该方法在磨溪雷一1气藏的合理应用，有效指导了气藏后续提采措施的实施，并为非均质性强、储层认识度不够的气藏如何合理预测可采储量提供了借鉴作用。

Abstract: The reservoir heterogeneity of Moxi Lei-1¹ gas reservoir is strong, with the characteristics of medium porosity and ultra-low permeability. There are differences in the degree, the understanding of reservoir and sequence of reserves utilization in each exploited block, which makes it difficult to accurately evaluate the recoverable reserves. It is difficult to reasonably guide the production plan and its error is often large if a single method is used to evaluate the recoverable reserves. In order to study the influence of reservoir permeability and allocation on recovery ratio, and preliminarily demarcate the recovery range of the target reservoir, firstly the depletion simulation experiments with the low permeability, high permeability and low-high permeability series by using the target layer cores were designed and carried out. Then analogy method was applied according to the previous research results of the different reservoir types and the abandoned conditions in further refining the recoverable reserves of the target reservoir. Further, production decline method is used to optimize the target reservoir recovery according to the statistical results of normal production decline rate in different wells. Finally, pressure-drop method is used to obtain the most reasonable recovery according to the actual shut-in data of typical wells, and reasonably predict the recoverable reserves in each block. The application of this method in Moxi Lei-11 gas reservoir can effectively guide the implementation of subsequent measures for enhancing recovery ratio, and provide a reference for how to reasonably predict the recoverable reserves of gas reservoirs with strong heterogeneity and insufficient understanding.