复杂气藏型储气库先导试验方案设计方法

国内现役地下储气库(以下简称储气库)的工作气量和调峰能力等关键参数达标率偏低,究其原因有可能是未及时开展先导试验对关键参数进行现场验证与核实,对储气库高强度快速往复注采所引起的关键特性认识不清,从而降低了方案指标的可靠性。为此,参照气藏开发先导试验定义,涵盖试验依据、试验目的、实施节点、试验内容等,首次建立了复杂气藏改建储气库先导试验方案设计方法。研究结果表明:①先导试验的核心要求是"科学性、安全性、经济性";②先导试验的主要内容包括圈闭密封性验证、有效建库空间定量评价、短期高速注采气能力核实、老井封堵工艺适应性评价和低压储层建井工艺适应性验证等5项;③先导试验方案包括优选试验井、部署现场试验和配套专题研究;④现场测试涵盖产能、连通性、边界和气液界面变化;⑤配套专题研究包括地质特征、注采机理、注采效果和钻采工艺。结论认为,该方法已成功应用于中国石油吐哈油田公司和中国石油吉林油田公司,指导了储气库先导试验方案设计和现场实施,为可研方案关键指标设计提供了新的认识和科学依据,有助于提升我国复杂气藏型储气库的设计水平和建库指标的可靠性。

A method for designing the pilot test scheme of underground gas storage rebuilt from complex gas reservoir

The reasons for a low standard-reaching rate of the key parameters (e.g. working gas volume and peaking shaving capacity) of domestic in-service underground gas storages (UGSs) may be that a pilot test is not carried out in time to verify and check the key parameters on site and that the key characteristics resulting from cyclic injection and withdrawal of high intensity and high speed are not understood sufficiently, which reduce the reliability of scheme indicators. Referring to the definition of the pilot test of gas reservoir development, this paper for the first time developed a method for designing the pilot test scheme of the UGS rebuilt from a complex gas reservoir in terms of test basis, test purpose, implementation node and test content. And the following research results are obtained. First, the core requirement of a pilot test is scientificity, safety and economy. Second, the main content of a pilot test mainly include the verification of trap sealing capacity, the quantitative evaluation of effective UGS construction space, the check of short-term high-speed injection and withdrawal capacity, the adaptability evaluation of old well plugging process, and the adaptability verification of well construction technology in low-pressure reservoirs. Third, a pilot test scheme is composed of test well selection, field test arrangement and supporting monographic study. Fourth, a field test covers productivity, connectivity, boundary and gas-liquid contact change. Fifth, the supporting monographic study focuses on geological characteristics, injection and withdrawal mechanisms, injection and withdrawal effects, and drilling and production technologies. In conclusion, this method has been successfully applied in Tuha and Jilin oilfields operated by PetroChina to guide the design and field implementation of the UGS pilot test scheme. The research results provide new understanding and scientific basis for designing key indicators of feasibility study scheme and are conducive to improving the design level and construction indicator reliability of UGSs rebuilt from complex gas reservoirs in China.