TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThis paper presents the results of a wide-ranging investigation into the application of high power sound waves for the removal of plugging material from the wellbore and near wellbore region. The paper describes the process of generating high power sound waves using a high voltage electrical discharge and also summarizes the results of the laboratory and test well trials conducted on both simulated plugging materials and also on mud cake. The paper also references progress on the development of a prototype wireline conveyed wellbore cleaning system. The results of the investigation concluded that high power sound waves represent a viable wellbore cleaning technology with the potential to be applied effectively in the removal of various forms of wellbore plugging material. Since this process can be applied selectively and in a controlled manner in the wellbore, without environmental impact and using standard wireline deployment techniques, it offers considerable benefits over some of the existing solutions.

Real time reservoir monitoring is critical for the effective management of any reservoir. Permanently installed reservoir monitoring instrumentation is generally installed as standard practice in the majority of offshore wells and whilst the reliability of such systems has improved significantly over the last decade, there are still many examples of wells around the world where these systems have failed prematurely. The Mungo Platform, located in the UK Central North Sea, has several wells in which the permanently installed monitoring systems failed early on in the life of the wells. In the absence of any real time reservoir pressure / temperature data, a compromise solution has been to install long term memory gauges in the wells so that reservoir monitoring, all be it using historic data, has been possible. Being relatively compact in size and a Normally Unmanned Installation (NUI), well intervention operations on Mungo are logistically challenging, with limited deck space for rig up and with personnel having to shuttle from the Marnock platform located around 24km away. A newly emergent wireless reservoir monitoring technology that can be retrofitted into existing wells and can transmit data to surface in real time was viewed as an attractive alternative to performing regular well interventions to gather historic data using memory gauges. Whilst the wireless gauge technology has a growing track record in the subsea and onshore well environments, signal attenuation in the offshore platform environment presents particular challenges that had previously prevented the technology from being retrofitted into such wells. A concept was developed for offshore platform wells having failed permanent cabled gauge systems, whereby the cable and gauge infrastructure of the failed permanent gauge system should, under the right conditions, act a conduit for the wireless gauge signal to be transferred to surface. To test the theory, a proof of concept trial was performed in Mungo well W160. A wireless gauge system was retrofitted into the well using standard slickline equipment and real time reservoir pressure and temperature data was successfully transmitted to surface using the failed permanent gauge system as a signal pick-up. This world first successful retrofit application of a new wireless monitoring technology into an offshore platform well, marks a milestone achievement in enabling the restoration of real time reservoir data without having to perform a well workover. This technology breakthrough is of significance in many situations where cabled in-well monitoring systems have failed. Collecting real time data from well W160 provided several benefits; the well production could be optimised on a daily basis, pressure build-up analysis could be performed, a new well target location was determined and the reservoir panel water injection response was optimised. Introduction The BP operated Mungo Field is located at the edge of the Eastern Central Graben in the UK sector of the North Sea, about 240km east of Aberdeen and sits in around 90m of water. First discovered in May 1989 it was developed as part of the Eastern Trough Area Project (ETAP) and saw first production in 1998. (See Figure 1) Mungo is a large oilfield with a small natural gas cap. The productive Forties, Lista and Maureen formations, which are Palaeocene sandstones, ring a salt diapir. The field has been developed under combined water and gas injection on a NUI located above the field. The Mungo NUI is tied back to the central processing facility (CPF), which is located over the Marnock field. The CPF handles the fluids produced by Mungo and also serves as the accommodation base for personnel shuttling to the Mungo NUI.

fax 01-972-952-9435. AbstractReservoir connectivity is a key uncertainty when considering field appraisal and development options. Reducing this uncertainty can provide significant benefits in optimising the field development plan. Through the application of new wireless telemetry technology (Expro CaTS TM ), a fully abandoned subsea appraisal well has been cost effectively converted into a valuable reservoir monitoring asset.Clair Ridge appraisal well 206/8-13Y was drilled in 2006 and located some 8km from the existing Clair production platform. The well was the first step in an appraisal programme designed to confirm the next stage of development of the Clair Field. Reservoir connectivity and the risk of compartmentalisation are key uncertainties for development of the Clair reservoir (ref.1).On completion of testing operations, the well would typically have been permanently abandoned and of no further value for reservoir monitoring purposes. By installing a battery powered, wireless pressure monitoring system in the well at the time of final abandonment, it was possible to monitor for any fluctuations in the reservoir pressure in the Clair Ridge resulting from production / injection events on the Clair platform. This newly emerging wireless telemetry technology transmits data from the reservoir to the seabed using the well casing as the communication path and advantageously, the signal is not attenuated by the presence of cement or bridge plugs in the wellbore. The reservoir pressure and temperature data that is transmitted up the casing, is collected and stored by a CaTS subsea receiver located on the seabed. The stored data can be recovered, on demand, by a supply vessel located overhead using well established through seawater acoustic communications.The use of a wireless gauge enabled a downhole well abandonment to be performed. The traditional method for

Summary There are many examples of wells around the world today that are shut in because of failure of surface-controlled subsurface safety valves (SCSSVs). While these valves are generally very reliable, the control line that runs to the surface in the annulus is susceptible to plugging by contaminants in the hydraulic control fluid and also to corrosion, which causes leaks; both are outcomes that render the valve inoperable. The failure of the control line also means that the contingency solution of installing a wireline-retrievable surface-controlled subsurface safety valve (WR-SCSSV) is not possible. When a safety valve fails, the most common remedial solution today involves installing a subsurface-controlled safety valve (SSCSV), such as an ambient valve or storm choke. While this solution is lower cost and more straightforward than performing a full rig-based well workover, it is not as safe. SSCSVs are directly influenced by changing well-flow conditions, such as high flow rates and low pressures, or by water slugs, and thus are notoriously unpredictable in operation. Additionally, they are not controllable from surface and not fail-safe, which is undesirable from a wellcontrol and safety standpoint. By transmitting electromagnetic (EM) signals from surface to downhole, it is possible to control downhole hardware. A wirelessly controlled safety valve has been developed that can be retrofitted into a well using conventional slickline intervention equipment and procedures. Being controllable from surface and of a fail-safe closed design, this valve offers both functional and safety advantages over existing SSCSV solutions. This new valve also offers a retrofittable solution for wells having no hydraulic control line installed. In situations where a capillary string may need to be installed for foam- or chemical-injection purposes, it also provides an opportunity to free up the hydraulic control line. A prototype valve was subjected to qualification and functionality testing in accordance with a modified International Organization for Standardization (ISO) 10432 test procedure. This testing was followed by installation in an onshore gas well for a 6-month trial that involved both flowing and injection phases. The valve was cycled and inflow-tested regularly and performed reliably, consistently, and fully in accordance with specification throughout the trial period. This successful trial of a new wirelessly controlled safety valve marks the introduction of a more-controllable and -predictable alternative to an ambient valve or storm choke, minimizes deferred production, and increases the well's safety. Following the successful onshore trial, the valve is now considered ready for wide-scale field application onshore, and at the time of writing this paper, plans for performing a first trial on an offshore platform are well advanced.

This paper presents the results of a wide-ranging investigation into the application of high-power sound waves to remove plugging material from the wellbore and near-wellbore regions. This paper describes the process of generating high-power sound waves with a high-voltage electrical discharge and summarizes the results of the laboratory and test-well trials conducted on both simulated plugging materials and mudcake. The paper also references the development progress of a prototype wireline-conveyed, wellborecleaning system. The results of the investigation concluded that high-power sound waves represent a viable wellbore-cleaning technology with the potential to be applied effectively in removing various forms of wellbore-plugging material. Because this process can be applied selectively and in a controlled manner in the wellbore, without environmental impact and with standard wirelinedeployment techniques, it offers considerable benefits vs. some existing solutions. A high-energy electrical discharge, which may be of the order of several hundred joules, is triggered at a spark gap submerged in an electrolyte. Typical electrical-breakdown times in water can be engineered to occur in the nanosecond time scale. A high current flows from the anode to cathode, which causes the electrolyte