Examples of discriminating the downward depth and downward timing of the velocity string in the water-producing gas well

Jing Yang,Xin Fan,Desheng Zhou,Yan Le,Minhao Guo,Haiyang Wang,L Wang,V Yepes

doi:10.1051/e3sconf/202124801072

Abstract

The problem of bottom hole effusion is an important reason for the reduction and even shutdown of natural gas wells. Downward velocity string is an important drainage gas recovery process, which can improve the flow rate of gas and discharge more liquid from the wellhead. However, the depth and timing of the velocity string is a technical problem that has been difficult to solve by field engineers. To solve this problem, this paper designs a method to select the depth and timing of the velocity string in the case of highly deviated wells and applies this method to Well X6–2 and Well X2–1 of PCOC in Ordos Basin, China. The optimization results show that when the wellhead pressure is 6.26 MPa, Well X6–2 should lower the 2–1.71 in. or 2.375–1.995 in. velocity string to 3337.9 m before the formation pressure decays to 8.800 MPa, which is most conducive to improve the liquid carrying capacity of gas wells. When the wellhead pressure is 4 MPa, Well X2–1 should lower 2–1.71in. velocity string to 3401.3 m before the formation pressure decays to 5.800 MPa, or lower 2.375–1.995 in. velocity string to 3401.3 m before the formation pressure decays to 5.900 MPa.

Highlights

Natural gas is the main energy source for the development of the national economy
It is found that the actual flow rate of gas in each part of the wellbore in the vertical section of Well X6-2 and Well X2-1 is higher than the critical liquid carrying flow rate, so there is no fluid accumulation in the vertical section
The actual flow rate is much higher than the critical flow rate, and the liquid carrying capacity of the gas well is enhanced and no effusion is produced

Summary

Introduction

Natural gas is the main energy source for the development of the national economy. natural gas extraction is always accompanied by liquids from condensate oil and water. You can replace the tubing with a smaller size to enhance the gas flow rate and its liquid-carrying capacity, thereby discharging the liquid from the well It is called the velocity string drainage gas recovery technology. It can be seen from the above literature that the depth and timing of the velocity string have always been technical problems that are difficult for field engineers to solve, and the main reliance is still on empirical judgment. This identification method can provide a reference for oilfield engineers

Basic data of the well and design process

Determination of the downward time of velocity string in Well X6-2

Determination of the downward time of velocity string in Well X2-1

Conclusions