Downhole Pressure Controlled Plunger Gas Lift Research and Application in Block Su75 of Sulige Gas Field

Abstract

Abstract-Block Su 75 of Sulige gas field belongs to low permeability, low pressure, and low abundance gas reservoir and the number of the wells producing water has been arising year by year, which means the problem which is called as liquid loading has become the main factor influencing the gas well deliverability. Plunger gas lift is one of the important drainage gas recovery technologies to extend the flowing production period of gas wells for it has high automation degree and is easy to manage. While during the field application, its low drainage gas recovery efficiency and bad stimulation effect occurs. So downhole pressure controlled plunger gas lift technology was developed and the field test in Su 75-26X well got better effect. Through practice, downhole pressure controlled plunger gas lift technology has high drainage gas recovery efficiency, for the technology is designed to use reservoirs energy fully, and the plunger is controlled automatically by pressure under the ground rather artificially on the surface. Obviously, downhole pressure controlled plunger gas lift technology has wide popularization and application foreground in Sulige gas field.Keywords-Sulige gas field; liquid loading; drainage gas recovery; plunger; gas lift; field application I. OVERVIEW Block Su 75, which is located in the west of Sulige gas field and has low structural position and serious gas/water difference, has serious water production situation. The proportion of the gas wells producing water is 86.9% and the production of gas wells producing water, accounts for 75.5% of the daily gas production of Block Su 75. In order to ensure stable production of the block, the drainage gas recovery technology is promoted in the well site in a large scale. Among them, the conventional plunger gas drainage technologies achieved good results in field application, but there are the following shortcomings: 1. For the gas wells with low gas production and much liquid loading, the plunger often can not effectively run to the wellhead,. 2. The setting depth of plunger is relatively shallow and the fluid which is located in the lower depth can not be excluded, 3. The ground control systems is difficult to manage. Therefore, to solve the defect of the conventional plunger drainage gas recovery technology, downhole pressure controlled plunger gas lift technology was developed, to reduce ground equipment maintenance workload and improve the drainage efficiency. II. DOWNHOLE PRESSURE CONTROLLED PLUNGER GAS LIFT TECHNOLOGY PRINCIPLESA. Operating Principle Downhole pressure controlled plunger gas lift technology [1] was developed in the case that the drainage efficiency of the conventional plunger gas drainage technologies that was used to weakly natural flow wells or those wells with low gas/liquid ratio, is very low. Pressure controlled plunger and sealed working barrel are designed for the technology [2] [3]. And with those structures the well will be closed when the plunger fall into the working barrel and the well will be open when the pressure b...