Wireless Transfer Successfully Transmits Bottomhole Data During Drill-Stem Testing in a Multi-Well Program Offshore Gabon

Abstract Conducting a drill stem test (DST) to gather data to evaluate the potential of a new field is a common practice in the oil and gas industry. In the past, gathering this data was performed by running a surface read-out tool in the drill string. Then, wireline would be used to deploy a tool into the well and latch it into a surface readout (SRO) tool downhole. Bottomhole data could then be generated during well shut in. This method worked satisfactorily for shut-in periods; however, this scenario was difficult to achieve while flowing the well. This paper will discuss an innovative real-time subsurface data acquisition solution that uses a state-of-the-art Acoustic Telemetry System (ATS) to gather data both during the flow period as well as when the well is shut in, thus allowing realtime readout at the surface. The new system distinguishes itself from conventional surface readout (SRO) systems because it sends data through the tubing wall using acoustic energy rather than running a probe using wireline to latch into the gauges as is the case with traditional systems. Pioneer Natural Resources successfully used the acoustic telemetry system to transmit bottomhole pressure and temperature data to the surface in real time during four separate drill stem tests in three different exploratory wells offshore Gabon. This was the first time this new technology had been used on a multi-well project. The data that were transmitted from down hole matched the data that were downloaded from the downhole memory gauges that were retrieved when the DSTs were ended. The ATS was capable of providing accurate surface readout data from the beginning of the test, allowing Pioneer to better understand the downhole conditions, and consequently, execute a DST that could meet all the objectives for testing in these zones. In addition, since there were risks that sand production, paraffin deposition, and low pour-point crude could impair the integrity or stick the wireline if it were used for data transmission in these wells, the ATS enabled the needed information to be retrieved without compromise to safety or the environment. Introduction The scope of a DST can range from a basic test (such as an openhole test in an onshore area in which there is no flow to the surface) to a complex, cased-hole test (such as one that would be run in the North Sea flowing at surface for many days).1,2,3,4 Analysis of the DST data is used for making decisions concerning completion/field development or drilling continuation. The data acquisition is defined by the test parameters, which generally require both surface and downhole inputs. Usually, bottomhole data acquisition has been performed by a surface read-out (SRO) system, and wireline in some form (braided or slickline) is needed. The traditional drill stem testing procedures use wireline to deploy probes to acquire whatever information from downhole is needed to obtain the information required.