Retrievable Socket Electronic Memory Recorder as a New Method of Bottom Hole Pressure and Temperature Survey in a Mature Field
Authors: Azhim Luthfan Nur , Pratama Satria , Aryawan I Gusti Ngurah , Pranata Angga , Renaldo Wan , Aullia Diandra , Wibawa Agung , Mulyanagara Guntur , Kuncoro Anang Arie 
Published: March 2023

This paper presents a valuable new method from Pertamina Hulu Rokan Zona 4 in the bottom hole pressure and temperature (BHPT) survey. Nowadays, the conventional method and gradient pressure acquisition is only able to be done by using a slickline after swabbing job, because during swabbing job, the swabbing tool string is used inside the tubing. Unfortunately, there are missing data when influx from the reservoir occurred, due to the shut in condition may not always represent the overall characteristic of a well.

Retrievable Socket Electronic Memory Recorder (Retrisock EMR) consists of seating parts with deliverable and retrievable mechanisms. Engineering design was done to ensure it will be suitable for acquiring data during swabbing job without a slickline unit. Once Retrisock EMR is put inside the tubing, it is possible to record data starting from run in hole tubing, pressure test packer, swabbing job, and pressure build up to static gradient pressure temperature. It could be retrieved without pulling out tubing from the well to download the data, nevertheless, the data may be uncertain for further analysis. The advantage, it could be put back into the tubing by using a sand line rig.

Pressure and temperature were obtained during swabbing job to represent the influx from the reservoir into the well. The graph of pressure can be approached as well testing, such as a modified isochronal test which can be processed to pressure transient analysis for further determination of skin value, reservoir boundary, and permeability. A combination of total volume recovered during swabbing job and pressure transient analysis result become a reference for whether well stimulation is needed or not, before the well start to produce. The result of static gradient pressure analysis will estimate the static fluid level and could be used as a measured gradient of fluid in a well for calculating the inflow performance relationship (IPR) precisely. The result of implementation in Talang Akar Formation, West Benakat Structure, well BKB-272 production increased significantly from 600 BFPD to 800 BFPD after evaluation by using data from Retrisock EMR measurement. Two more promising benefits of Retrisock EMR are time and cost efficiency. Based on study and implementation, it can reduce operation time 10 hours faster. Then, the impact of faster operation time is less operation cost.

The tool and method presented in this paper provide a valuable concept for well optimization in developing BHPT survey before and after stimulation to compare the reservoir influx without pulling out tubing string and slickline. Another opportunity is a BHPT survey without shut in the well in the oil well producer while it on production by using an artificial lift electric submersible pump (ESP) that was not equipped with the downhole sensor as a real-time monitoring tool.