Ultimate Data Acquisition Surveillance Technology Succeeded to Maximise Well's Productivity and Deepen POI for the Unstable Flowing Gas-Lifted Well
Authors: Elshourbagi S. M. , Yeo C. H. , Salleh Mohd. F. , Mawardi Z. 
Published: February 2024

In Southeast Asia, specifically the land and, in general, the offshore oil operating assets, most of the wells in production are operated with the assistance of gas-lift, accounting for about 75% of the total active wells. Gaslift is a major type of artificial lift methods that involves injecting high-pressure gas from the casing into the tubing via gaslift valves. Gaslift mandrel spacing design frequently contains several challenges However, by regularly monitoring well operating condition at the surface, compared to the conventional costly wireline FGS data points, the production technologist engineer will be able to get a close overview of the performance of a gas-lifted well. WellTracer® technology is currently adopted and captured as a routine surveillance plan in the well reservoir management strategy for the purposes of evaluating well performance flowing condition, as well as providing information for consideration of options to maximize well deliverability, increase oil production, and identify gas savings opportunities.

As a part of the introduction to WellTracer® technology, it is known that the only method available to production operations to determine if a gas-lift valve is open or closed downhole was to run an FGS to determine the pressure and temperature data points of the fluids in the tubing. There are also times that the producing well is not flowing steadily. In these cases, the FGS survey becomes inconclusive due to fluctuation of the surface flowing pressures. WellTracer® technology was introduced initially as a pilot trial in which the WellTracer results indicated this method is effective for the cases of unstable flowing conditions in which the routine FGS cannot be evaluated. The WellTracer® analysis and findings provide a reasonable determination of the lift gas entry points in the well. The method can identify the operating lift depth, verify multiple points of GL injection, and indicate the possibility of tubing leaks.

Downhole pressure and temperature data cannot be obtained from CO2 tracer surveys. However, this technology can still be used as an option to replace FGS for the following reasons: Firstly, minimize well entry for equipment hook-up or shut-in the well, therefore production deferment can be minimized, and potential for no oil spell, green environment and meeting HSE industry standard. Secondly, no downhole tool is required in the wellbore, well intervention failures, reduces non-productive time (NPT), and risks. Thirdly, it is preferable for slugging wells, highly deviated well, or downhole mechanical or scale obstruction. It is preferable to conduct a survey on dual-string completion to determine gas-lift injection split. It is also possible to quantify gas-lift injection through each of the operating injection points in a well. As a summary, capability of downhole data acquisition at the wellhead for the gas-lifted producer without oil deferment.

This document will elaborate more on the project objectives, the interpretation of the results, and the value gained from the surface data acquisition form the survey results and way forward proposals.