Innovative Rigless Well Test Solution with Powered Sub-Surface Shut-In Wireless Telemetry System to Enhance Dynamic Reservoir Characterization Cost-Effectively

Abstract

Abstract A key part of dynamic reservoir characterization is pressure transient analysis, which is essential in understanding near wellbore and far field formation properties. Acquisition of this pressure data via downhole shut-in with drill-stem tests (DST) are preferred in the exploration and appraisal stages of a well to get reliable reservoir information. Acquiring this pressure transient analysis via a downhole shut-in avoids wellbore noise, wellbore storage effect and wellbore fluid segregation effect which can mask part or all the reservoir characteristics in the acquired data. Unfortunately, DST operations may not work for all wells due to rig availability, time constraints and simply because there might already be a permanent completion in the well. This paper shows a well test technique with a slickline or e-line conveyed downhole shut-in tool with wireless telemetry system to get precise build-up data for reservoir characterization. We'll also demonstrate how a real-time data acquisition system can enhance the efficiency of Well test durations. Slickline or E-Line conveyed downhole shut-in tools (DHSIT) were developed to acquire pressure transient analysis where DST is not possible. These tools consist of a multi-cycle valve, electronic timer, actuator and battery. Typically, DHSIT are run with memory gauges below and hung in the tubing or casing via a lock mandrel or nipple-less packer. Once conveyed into the well, predetermined test program is run of specific flowing and shut-in periods to acquire the pressure transient. As the valve operation is based on a pre-programmed timer with memory gauges, an estimate of the time required to good quality data and radial flow must be estimated before the job. Due to reservoir and well variations, this can inherently lead to either reduced data quality if the testing program is ended too early or inefficient operations if data is acquired too long after achieving radial flow. In this new application, the DHSIT is equipped with downhole gauges with acoustic data transmission capabilities. When the pre-determined shut-in time is reached, the DHSIT closes instantaneously to initiate the build-up period. Data from the downhole gauges can be retrieved by conveying an acoustic repeater above the DHSIT with electric line and acquiring both historical and real-time data from below the DHSIT without any mechanical contact with the gauges. All the data in the gauge memory, starting from the data acquired while running the DHSIT in hole can be transmitted to surface through this hybrid real-time acquisition system. All the data can be streamed automatically from the downhole gauges into well test interpretation software with no manual data handling. The stand-alone DHSIT with acoustic downhole gauges was used successfully in a trial well, for the first time in the UAE. The pressure data from the gauges below the DHSIT was sent acoustically to a wireline-conveyed acoustic data transmitter. The data was obtained on-demand for Petro-technical experts to analyze continuously. A digital, seamless connection between the downhole pressure measurements and the interpretation software was created through customized software that avoided manual human interference. The system that was tested for this study improve the data quality with downhole shut-in ability and provide real-time insights about the pressure transient data to optimize build-up duration by terminating the test when sufficient data is acquired and avoiding unnecessary and costly deferred production.