超音速雾化排水采气工艺数值模拟与现场应用

Numerical simulation and field application of supersonic atomization and drainage gas recovery technology: A case study on the middle-shallow gas reservoirs in the Western Sichuan Depression

符东宇 王雨生 姜超 严小勇 鲁光亮 黄文杰 魏朝勇

FU Dongyu WANG Yusheng JIANG Chao YAN Xiaoyong LU Guangliang HUANG Wenjie WEI Chaoyong

中国石化西南油气分公司勘探开发研究院 中国石化西南油气分公司采气一厂 中国石化西南油气分公司

Exploration and Development Research Institute, SINOPEC Southwest Oil & Gas Company, Chengdu 610041, Sichuan, China No.1 Gas Production Plant, SINOPEC Southwest Oil & Gas Company, Deyang 618000, Sichuan, China SINOPEC Southwest Oil & Gas Company, Chengdu 610041, Sichuan, China

针对超音速雾化排水采气工艺在川西坳陷中浅层气藏应用缺乏理论指导的问题，开展了数值模拟研究及现场试验。首先，基于川西坳陷中浅层有水气藏生产井实际工况建立了超音速雾化喷管数值模型，围绕气井生产动态特征开展了喷管两相流数值模拟，并通过室内实验结果验证了模型正确性，通过求解获得了雾化喷管内部流体各相流动特征参数的分布。对气井生产特征参数以及喷管结构参数进行了敏感性分析，明确影响超音速雾化排水采气工艺应用效果的主控因素，形成了适用于川西坳陷中浅层气藏的超音速雾化排水采气工艺理论。研究表明：喷管渐缩段对于流体流动特性影响较小，而流体流经喷管喉部至渐扩段，各特征参数发生剧烈变化；气体流经雾化喷管被加速达到音速时，临界压力比值为1.35，该数值可作为判断工艺有效性的技术指标；入口压力对工艺效果整体影响较大，而产气量及气液比则主要通过控制喷管入口前井段的携液来影响工艺效果，被气流携带进入喷管内部的积液均在超音速气流作用下实现雾化。基于理论研究设计了施工参数，优选气井开展了现场试验，结果表明超音速雾化排水采气技术可实现气井节流稳压的同时强化见水气井的携液能力，改善井筒流态，降低井筒压力损失，对延长川西坳陷中浅层气井稳产期具有重要意义。

In view that the application of supersonic atomization and drainage gas recovery technology in the middle-shallow gas reservoirs of the Western Sichuan Depression is lack of theoretical guidance, this paper carried out numerical simulation researches and field tests. Firstly, the numerical model of supersonic atomization nozzle was established based on the actual working conditions of production wells in the middle-shallow water bearing gas reservoirs of Western Sichuan Depression, and two-phase flow in the nozzle was numerically simulated focusing on the production performance of gas wells. Then, the correctness of the model was verified by means of laboratory experiment, and the distribution of the flow characteristic parameters of each phase of the fluid inside the atomization nozzle was solved. Finally, sensitivity analysis was carried out on gas well’s production characteristic parameters and nozzle’s structural parameters, and the main factors influencing the application effect of supersonic atomization and drainage gas recovery technology were determined. In addition, theories of supersonic atomization and drainage gas recovery technology suitable for the middle-shallow gas reservoirs of the Western Sichuan Depression were formed. It is indicated that nozzle’s convergent section has less influence on the flow behavior of fluid, while characteristic parameters of fluid change greatly when it flows through nozzle’s throat and divergent section. When the gas is accelerated to the acoustic velocity while flowing through the atomization nozzle, the critical pressure ratio is 1.35, which can be taken as the technological indicator to judge the technological effectiveness. The inlet pressure has greater influence on the overall technological effect, while the influences of gas production rate and gas/liquid ratio on the technological effect are mainly reflected through controlling the liquid carrying in the hole section before the nozzle inlet and the liquid loading which is carried into the nozzle by the gas is atomized under the action of supersonic gas flow. Based on theoretical researches, the construction parameters were designed and gas wells were selected to perform field tests. It is revealed that supersonic atomization and drainage gas recovery technology can achieve throttling and pressure stabilization of gas wells while enhancing the liquid carrying capacity of water producing gas wells, improving the flow regime in the well and reducing the pressure loss in the well. The research results are of great significance to prolong the stable production period of middle-shallow gas wells in the Western Sichuan Depression.

10.13639/j.odpt.2020.03.012