Liquid loss from a storage tank is generally caused by localized material failure in the form of localized corrosion. Tank bottom leaks can be a result of improper foundation design or operating a tank outside the recommended design pressure or temperature boundaries. Product liquid leakage remains a significant environmental concern. Tank design options that reduce the risk of a leak can be considered, or in the event of a leak, any product that escapes is contained and detected in a realistic time frame. Design options are generic with respect to the type of storage tank.
Environmental hazards can be reduced or prevented by the proper choice of chemical additives at optimum concentrations. Pressure tests are performed with water or brine to ensure the absence of leaks in pressure piping, tubing, and packer. Leaks on the surface can endanger service personnel, and subsurface leaks can cause subsequent corrosion of tubing and casing in the annulus. Anyone around acid tanks or pressure connections should wear safety goggles for eye protection. Those handling chemicals and valves should wear protective gauntlet-type, acid-resistant gloves.
A simple, practical, and reliable method to detect a gas leak under the conditions of unknown inlet or outlet gas rate, or unknown inlet or outlet pressure, is highly desirable. Tube leaks present in a water-cooled sulfur recovery unit (SRU) condenser can lead to a variety of process issues, including corrosion and the oxidative formation of acidic species. This work devised a novel method to verify such leaks within a SRU condenser.
Flaring and emissions challenges have recently made news headlines around the world. The goal of this article is to engage you with this important topic by presenting a selection of recent SPE papers which address these challenges through various approaches. Methane monitoring using improved methods is detecting more gas in the atmosphere, increasing the need for better ways to eliminate releases. With the API and a multi-operator group passing separate programs aimed at reducing methane emissions, the discussions on what defines an acceptable level of regulation continues within the industry. The amount of natural gas flared has plunged in North Dakota, a region that has been the leader by far in gas wasted because gathering systems could not hook up the wells fast enough.
As the oil and gas industry is moving towards digital oil field, the selection of leak detection system (LDS) has become more crucial. Early detection of leaks not only saves environment from Hazardous hydrocarbons but considerable loss in production is also saved. This paper discusses about both internal and external LDS and its applicability for onshore and offshore fields. This paper will ease the selection process of LDS for green and brown fields of both offshore and onshore installation.
Wellbore integrity is very critical in oil and gas industry and needs to be maintained through the entire cycle of well's life. The most important item for well integrity is to set cement between two casings or between casing and formation. A good cement job provides isolation and protection for the well and a poor cement job can have cracks and allows corrosive fluids to migrate through micro channels.
Downhole casing repair is a common workover operations worldwide, especially in wells that have been producing over number of years. It is very challenging to control corrosive fluid migration which slowly corrodes casing and tubing over time. An innovative epoxy resin formulations has been developed and tested in the field to repair casing leaks which is extremely easy to handle and very economical. A cost-effective workover program can be developed and implemented depending on the severity of the leak.
The improved approach of using innovative resin can be used by mixing with cement blends to repair major casing damage and can also be used as standalone application to fix minor leaks. The system maintains extremely good rheological properties even when mixed with cement. The system has ability to withstand high differential pressure and is also resistant to acid, salts, hydrocarbons and most importantly various corrosive liquids. The precise application is determined by measuring the injectivity of the well. In the low injectivity wells, only epoxy resin solution will be spotted and repair the damaged casing. In the high injectivity wells, the chemical will be mixed with cement and completely seal the damaged zone. The chemical will enhance the mechanical properties of the cement and will be more resilient to extreme down-hole condition.
The paper will emphasize the added value and potential of the method in restoring the casing integrity. The paper will also discuss the laboratory test reports and application which will highlight effective and economical outcome.
Operators in unconventional shales are continuously looking for ways to reduce potential emissions from production facilities. This is especially challenging in liquid-rich regions, such as the Marcellus Shale. As regulations and various industry best practices evolve, facility designs and equipment must evolve as well. Facility-design improvements and successful operational procedures were examined to eliminate or significantly reduce emissions (Porter et al. 2016).
By taking a proactive approach, operators can significantly reduce emissions. In a previous work (Porter et al. 2016), we discussed the key elements of a successful program: (1) a facility design and operational philosophy that considers emission controls, (2) a comprehensive maintenance program that addresses all unplanned or unintended releases encountered during optical-gas-imaging inspections and allows for feedback to facilitate corrective action, and (3) a focused plan for improving technology to diminish the quantity of future leaks. Applying enhanced technology and past experiences to older designs is often the most efficient measure for reducing potential emissions. While these elements are crucial, equally important is the historical defining and tracking of actual identified leaks and the documentation of corrective actions that were taken (Porter et al. 2016). This work further corroborates these key elements.
Additional facility designs for maximum emissions reduction were compared to facility designs in our previous work (Porter et al. 2016), using calculated emissions for each scenario. As well production increases (owing to longer lateral drilling and enhanced stimulation practices), wellsite liquid handling and vapor control become challenging. Techniques for effectively controlling vapors and mitigating emissions were explored in detail, using an actual case study. Also, a previous leak-detection field study with preliminary data was updated with additional years of data, which yielded further clarification of emissions released on a field and pad level with resulting variations in time. Detailed data analysis compiled from inspections identified the most common areas where leaks occur within a production facility—the majority of which were located on atmospheric stock tanks. Data further demonstrated the effectiveness of higher-quality tank relief valves for reducing fugitive leaks.
Production-facility emissions can be managed by using effective production-facility designs and technologies. The present work offers an improved understanding of how technological evolutions can support effective design solutions and processes in a modern shale-gas development (Porter et al. 2016).
Imrie, Andrew (Halliburton Energy Services) | Negenman, Brendon (Halliburton Energy Services) | Lee, Chung Yee (Halliburton Energy Services) | Iyer, Mahadevan S. (Halliburton Energy Services) | Parashar, Sarvagya (Halliburton Energy Services) | Shata, Mohamed Raouf (Halliburton Energy Services) | Helton, Sean (ConocoPhillips)
The identification of low-rate leaks along with low annular-pressure buildup rates in any type of completion presents challenges in the well-integrity domain. This paper emphasizes the importance of understanding the well-diagnostic problem to determine feasibility, isolate interest zones, enhance stimulation strategies, and ultimately optimize the acquisition of high-resolution acoustical data from the wellbore with a latest-generation advanced leak-detection tool.
This case study discusses the methodology that underlies the successful determination of the depths and the radial locations in the outer casing strings of multiple leaks in an offshore well. In the study presented, emphasis had been placed on the job planning to provide adequate or substantial leak stimulation for the accurate determination of the leak points in terms of radial distance away from the tool axis within the wellbore. Rather than a shut-in and flowing or venting acquisition, it was proposed that the optimal method for the successful determination of an outer casing string leak involved invoking a range of flow rates and, therefore, acoustic levels, across an extended period. The study also demonstrates the advantages of integrating acoustic-based tools with conventional production logging tools.
Two outer string casing leaks with annulus to formation communication areas were identified from high-resolution leak-detection logging coupled with conventional pressure and temperature measurements. The interpretation process included the computation of a 2D radial map of the flow activity across each zone of interest. This process resulted in less ambiguity and clearer results obtained in real time during the acquisition. The location of each leak point was triangulated using an error-minimization algorithm from the received acoustic waveforms at the tool receiver array. Further, the optimized stimulation strategy enabled leak-stimulation responses to be tracked in the computed power spectral density (PSD) at each leak. This process enabled the operator to promptly move on with the well abandonment strategy without waiting for further data analysis.
Attention to detail from the outset and a complete understanding of the well and its annular pressure and fluid behavior enabled an optimized and focused electric line diagnostic strategy to be used. The use of high-resolution acoustic data from an advanced leak-detection tool with an array of hydrophones ensured that the multiple leak locations were identified and characterized.