天然气地下储气库设计方案比较法

COMPARATIVE METHOD OF DESIGN PRO GRAMS FOR UNDERGROUND GAS STORAGE

我国地下储气库 (简称储气库 )优化设计技术研究尚未形成一套成熟的系统理论和方法。文章以枯竭气藏型储气库为研究对象 ,用储气库的投资和年操作经营费用构成储气库的年折合费用 ,并以此为目标函数 ,建立了储气库优化设计方案比较法的数学模型。模型中将储气库投资分解为储气藏、注采井、集输与净化设备、注气压缩机及辅助设施和垫底气等 5部分投资 ;将储气库年操作经营费用分解为气藏及注采井、集输及净化工艺系统和注气系统等 3部分操作经营费用 ,并建立了各部分投资和操作经营费用的计算公式。介绍了以“压力—流量平衡法”为基础的模型求解方法和步骤。该方法可得到储气库设计的多个方案 ,每个方案由不同套管尺寸下的天然气产量和井数、井底和井口压力、注气压缩机功率、储气开始和结束时的最佳储气量、方案的年折合费用等参数组成。该法在中石化中原油田分公司文 96地下储气库可行性研究的应用取得了好的效果。

A set of systemic mature theory and methods are not formed for optimized design technology of underground gas storages in China. Taking the gas storages with depleted gas reservoirs as research subject, taking the investment of the gas storages and annual operating cost to constitute the annual discounted cost of the gas storage, and taking it as the target function, the mathematical model of comparative method of optimized design programs for gas storages is developed. The investment of the gas storage is divided into 5 components, i. e. the gas-storing reservoir, the injection and recovery wells, the transmission and purification facilities, the compressors and auxiliary devices, and the cushion gas. The annual operating cost is divided into 3 components, i. e. the gas reservoir and injection and recovery wells, the transmission and purification processing system and the gas injection system. Also, the formula is made for calculation of investment or operating cost of each component. The method and procedure of the model resolution is introduced based on 'pressure-flow balance'. With the method, several programs for gas storage design can be obtained. Each program consists of such parameters as the production and number of wells with different size of casing, the pressure of bottom-hole and well-head, the compressor power, the optimum gas-storing volume when storing gas starts and ends, and the annual discounted cost, etc. It achieves good results to apply the method for feasibility study in Wen 96 underground gas storage of Sinopec Zhongyuan oil field branch.