螺杆式压缩机负压采气可行性分析及方案设计

Feasibility Analysis and Scheme Design on Application of Negative-pressure Gas Production by Screw Compressor Boosting

在气田开发中后期,一般采用活塞式压缩机增压开采维持气井生产,随着压力和产量的进一步降低,其运行工况的不适应和不经济性将进一步凸显。同时,对于即将进入定压降产开发模式的小产量低压气田,下步需要考虑增压开采。以中国石油西南油气田公司重庆气矿为例,结合小产量低压气田的生产实际,在分析总结川西使用螺杆式压缩机增压进行负压采气的运行效果基础上,进一步从机组性能、优缺点、适用条件、建设投资与运行成本对比分析等方面论证了重庆气矿使用螺杆式压缩机增压进行负压采气的可行性,认为对于井口油压低(略高于输压)、输压低(小于3.45 MPa)、产量小的气田或单井,使用螺杆式压缩机(单机处理量小于10×10~4m^3/d)增压进行负压采气,无论是从投资、日常的运行维护、提高采气速度还是提高最终采收率来说都较(活塞式压缩机)更具优势。另外,提出了应用初期使用螺杆式压缩机直接增压进行负压采气,中后期可考虑在增压机组前端设置"真空泵"的技术思路。

During middle to late development of numerous gasfields, piston compressor boosting is often devoted to maintaining a normal production. However, along with the continuous decrease of both pressure and yield, the running situation of these fields shows more and more apparent inelasticity and unbeneficial. Especially for those low-pressure and small-yield ones facing a development mode with constant pressure and reducing yield, pressure-boosting stimulation should be taken into account. In this study, taking Chongqing Gas Field of Southwest Oil and Gasfield Company as example, combined application effects of negative-pressure gas production by screw compressor boosting in gas production plant of western Sichuan area, the feasibility of negative-pressure gas production by screw compressor boosting got further ensure by analysis on unit performance, application conditions, construction investment and operating cost. With regard to some gasfields or single wells with low wellhead pressure(slightly higher than transmission pressure), low transmission pressure(less than 3.45 MPa), and small yield, to adopt screw compressor boosting(throughout of 10× 10~4 m^3/d per compressor) is superior to piston one in terms of the investment, daily operation and maintenance, and enhancing recovery rate and ultimate recovery. Finally the paper proposed a technological thought of using screw compressor at early stage and further installing a vacuum pump at the front of compressor during middle to late stages; finally drew up an application solution.