scholarly journals Controlling Condensate Gas Well by Lubricating and Bleed-Off Method, Case Study

2021 ◽  
Vol 4 (3) ◽  
Keyword(s):  
Safety Valve ◽  
Christmas Tree ◽  
Gas Well ◽  
Valve Malfunction

During flow a condensate gas well, downstream pressure dropped many times. The reason was partially plug which was occurred in choke manifold adjustable path due to producing abnormal cutting, junk and debris. Produced debris led to other problems such as malfunctioning in the Christmas tree and subsurface safety valve. The goal of this article is to present the procedure of lubricating and bleed-off method to control a gas well during production when there are malfunctioning in x-mas tree valves and subsurface safety valve. In this paper, other operations such as the Christmas tree substitution with a new one, installing and retrieving blanking plug, and mending subsurface safety valve malfunction are explained stepwise.

Solidifying Mud Cake to Improve Cementing Quality of Shale Gas Well: A Case Study

2015 ◽  
Vol 8 (1) ◽  
pp. 149-154 ◽  
Author(s):  
Jun Gu ◽  
Ju Huang ◽  
Su Zhang ◽  
Xinzhong Hu ◽  
Hangxiang Gao ◽  
...  
Keyword(s):  
Shale Gas ◽  
Calcium Silicate Hydrate ◽  
Drilling Fluid ◽  
Cement Slurry ◽  
Gas Well ◽  
Safety Requirements ◽  
Mud Cake ◽  
Gas Bearing

The purpose of this study is to improve the cementing quality of shale gas well by mud cake solidification, as well as to provide the better annular isolation for its hydraulic fracturing development. Based on the self-established experimental method and API RP 10, the effects of mud cake solidifiers on the shear strength at cement-interlayer interface (SSCFI) were evaluated. After curing for 3, 7, 15 and 30 days, SSCFI was remarkably improved by 629.03%, 222.37%, 241.43% and 273.33%, respectively, compared with the original technology. Moreover, the compatibility among the mud cake solidifier, cement slurry, drilling fluid and prepad fluid meets the safety requirements for cementing operation. An application example in a shale gas well (Yuanye HF-1) was also presented. The high quality ratio of cementing quality is 93.49% of the whole well section, while the unqualified ratio of adjacent well (Yuanba 9) is 84.46%. Moreover, the cementing quality of six gas-bearing reservoirs is high. This paper also discussed the mechanism of mud cake solidification. The reactions among H3AlO42- and H3SiO4- from alkali-dissolved reaction, Na+ and H3SiO4- in the mud cake solidifiers, and Ca2+ and OH- from cement slurry form the natrolite and calcium silicate hydrate (C-S-H) with different silicate-calcium ratio. Based on these, SSCFI and cementing quality were improved.

A Case Study of Hydraulic Fracturing Monitoring in Shale Gas Well Based on DAS

2021 ◽  
Author(s):  
S. An ◽  
X. Liang ◽  
G. Yu ◽  
D. Li ◽  
J. Wu ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Shale Gas ◽  
Gas Well

Subsea Gas Well Late Life Restart Lesson Learned: Failure Analysis and Operating Strategy

2021 ◽  
Author(s):  
Song Wang ◽  
Lawrence Khin Leong Lau ◽  
Wu Jun Tong ◽  
Kun An ◽  
Jiang Nan Duan ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Late Life ◽  
Flow Assurance ◽  
Gas Well ◽  
Subsea Pipeline ◽  
Operating Strategy ◽  
Root Cause ◽  
Financial Impacts ◽  
Transient Multiphase Flow

Abstract This paper elucidates the importance of flow assurance transient multiphase modelling to ensure uninterrupted late life productions. This is discussed in details through the case study of shut-in and restart scenarios of a subsea gas well (namely Well A) located in South China Sea region. There were two wells (Well A and Well B) producing steadily prior to asset shut-in, as a requirement for subsea pipeline maintenance works. However, it was found that Well A failed to restart while Well B successfully resumed production after the pipeline maintenance works. Flow assurance team is called in order to understand the root cause of the failed re-start of Well A to avoid similar failure for Well B and other wells in this region. Through failure analysis of Well A, key root cause is identified and associated operating strategy is proposed for use for Well B, which is producing through the same subsea infrastructure. Transient multiphase flow assurance model including subsea Well A, subsea Well B, associated spools, subsea pipeline and subsea riser is developed and fully benchmarked against field data to ensure realistic thermohydraulics representations of the actual asset. Simulation result shows failed restart of Well A and successful restart of Well B, which fully matched with field observations. Further analysis reveals that liquid column accumulated within the wellbore of Well A associates with extra hydrostatic head which caused failed well restart. Through a series of sensitivity analysis, the possibility of successful Well A restart is investigated by manipulating topsides back pressure settings and production flowrates prior to shut-in. These serve as a methodology to systematically analyze such transient scenario and to provide basis for field operating strategy. The analysis and strategy proposed through detailed modelling and simulation serves as valuable guidance for Well B, should shut-in and restart operation is required. This study shows the importance of modelling prior to late life field operations, in order to avoid similar failed well restart, which causes significant production and financial impacts.

Heavy Duty Wireline Fishing Operations in a HP/HT Sour Gas Well - a Case Study

2011 ◽  
Author(s):  
Gustioro Purwagautama ◽  
Idi Yusup Afandi ◽  
John M. Vincent
Keyword(s):  
Heavy Duty ◽  
Gas Well ◽  
Sour Gas
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