Research And Application Of Plunger Lifting Technology In Sichuan And Chongqing

Plunger gas lift technology is an economic, safe, efficient and energy saving drainage technology. It has been widely and successfully used in solving the water producing problems of Xujiahe gas wells in Sichuan and Chongqing area and Carboniferous gas wells in East Sichuan area. However, in the past practice all the required plunger gas lift tools were imported from foreign country and all the related job design service and maintenance service are supported by the foreigner too. In case there was something going wrong in or after the job, the problems arising cannot be addressed in a time manner due to the restriction of tool lead time or cost issue and it finally affected the continuous and steady production of the well. In order to solve this problem, we have developed a series of plunger gas lift tools based on the studies of existing plunger gas lift process design and work system optimization. We have carried out the field tests for the developed tools and the related job maintenance technique has been formed. In a summary, the studies and achievements are as following:(1) By carring out the studies of existing plunger gas lift process design and work system optimization, a specific set of plunger gas lift process design method suitable for Sichuan and Chongqing gas field is proposed and the optimized control mode for time and pressure is built.(2) In order to solve the problems of the displacement of the imported locking device and leaking of lubricator, a series of plunger gas lift tools such as bomb block type locking device and lubricator with thread seal are researched and developed. This will reduce the tool cost 30% or more and shorten the job cycle of the process well to one month.(3) In order to solve the problem that the imported controller cannot record or transmit the operating parameters, a new kind of controller which has a function of remote data transmitting and remote control is developed. This realized the digitization and intelligence of the plunger gas lift wells and hence greatly improve the maintenance efficiency of the well.(4) Concerning the production behavior of Sichuan and Chongqing gas wells, a standarized wellhead production process for plunger gas lift wells in Sichuan and Chongqing gas fields is proposed for ensuring the steady operation of the plunger.(5) The independently developed plunger gas lift tools and plunger gas lift process design method have been tested in 13 wells. The field test results showed that the developed tools are feasible, safe and stable, and the process design method meets the field production need. Over all the tested wells, the calculated accumulated test rate is 4,052.36x104m3,and the accumulated amount of water displacement is19045.05m3The application of the assembled self-developed plunger gas lift tools reduced the total cost of dewatering gas wells by plunger lift, laying solid foundation for the widespread use of this technique. It provides an economic, safe, efficient and stable drainage technology to rejuvenize the so called "Low pressure, low temperature and low H2S" gas wells in Sichuan and Chongqing area, further improving the well recovery rate.