Lolla, Sri Venkata Tapovan (ExxonMobil Upstream Research Co) | Bailey, Jeffrey (ExxonMobil Development Co) | Costin, Simona (Imperial Oil Resources Ltd) | Hons, Michael (Imperial Oil Resources Ltd) | Liu, Xinlong (Imperial Oil Resources Ltd) | Yam, Helen (Imperial Oil Resources Ltd) | Akhmetov, Arslan (ExxonMobil Canada Properties) | Hayward, Timothy (Imperial Oil Resources Ltd) | Brisco, Colin (Imperial Oil Resources Ltd)
Continuous subsurface surveillance is important for heavy oil in-situ recovery processes where induced stresses in the overburden can compromise the integrity of the wellbores. Wellbore failure may lead to the undesirable loss of fluids into the overburden. In recent years, there has been a rapid growth in the use of Passive Seismic monitoring systems to aid in subsurface surveillance activities, with the ultimate goal of detecting potential integrity issues as early as possible. However, the massive volume of data recorded by these instruments is time-consuming and error-prone to process manually. This paper introduces EMMAA (ExxonMobil Microseismic Automated Analyzer), an automated workflow to reliably process continuous microseismic data, detect subsurface integrity issues, and ultimately reduce the latency in responding to wellbore integrity issues.
A novel cloud-based technology for managing microseismic data is briefly described. The seismic waveforms, recorded by a distributed array of geophone receivers, are automatically analyzed to determine the type and source of subsurface disturbances (
First, novel frequency-domain and deep learning analyses are used to distinguish noisy signals from the seismic waveforms such as compressional and shear waves produced by the events. Next, the location of the event is calculated and its seismic attributes are computed. Finally, the type and severity of the seismic event are determined by an event classifier.
The performance of the automated workflow is examined in the context of accurate detection of casing failures in a heavy oil Cyclic Steam Stimulation (CSS) application. The event features that distinguish casing breaks from other seismic events are described. It is shown that the methodology is able to achieve a high detection rate when back-tested against a historical data-set of known casing failures. False positives are adequately contained by preventing waveforms of electrical or mechanical noise from being processed.
In a production environment, the event processing workflow is run on distributed servers and analyzes triggered seismic data in real-time. Depending on the severity of the microseismic events detected, operators are immediately alerted via email and text messages, so that remedial actions may be swiftly initiated. The utility of this integrated system is further exemplified by the massive reduction in the time taken to detect casing breaks—from up to 36 hours historically, down to less than one hour in most instances.
Extensions of EMMAA that enable the detection of a wide variety of microseismic events are also discussed. These events include surface casing slips that occur at the casing shoe, cement de-bonding events near the wellbores, and events indicative of potential fluid migration in the overburden.
Ghazali, Ahmad Riza (PETRONAS) | Abdul Rahim, M. Faizal (PETRONAS) | Mad Zahir, M. Hafizal (PETRONAS) | Muhammad, M. Daniel Davis (PETRONAS) | Mohammad, M. Afzan (PETRONAS) | A. Aziz, Khairul Mustaqim (PETRONAS)
The key objectives were to achieve better seismic resolution and spatial delineation in very heterogeneous reservoirs. We decided to supplement simultaneously the surface 3D multi component seismic acquisition by placing additional fiber optic live receivers in the subsurface via a "True-3D" experiment without shutting down the oil production. The most cost-effective method to snapshot this wavefield propagation downhole is by utilizing fiber optic Distributed Acoustic Sensing (DAS). The borehole 3D VSP data were acquired by sharing the surface OBN nodal survey airgun sources. This is an important experiment for the field in the future so that the need to halt insitu field production for 4D time lapse monitoring will not be required if the S/N is acceptable by using this method. This permanent installation of fiber optic cables has become our ears on wells, not only for 3D DAS VSP but for proactive monitoring of the field, ensuring optimum production performance throughout the life of the field.
Li, Baoyan (Baker Hughes, a GE Company) | Arro, Roberto (Baker Hughes, a GE Company) | Thern, Holger (Baker Hughes, a GE Company) | Kesserwan, Hasan (Baker Hughes, a GE Company) | Jin, Guodong (Baker Hughes, a GE Company)
For NMR logging of hydrocarbon bearing formations, the inversion of T2 echo trains is a critical pre-processing step to compute porosity, permeability, and fluid saturations of formations. To accurately and efficiently invert NMR measurement data, a new inversion method is presented to compute the optimal solution of T2 distribution with a unique optimal regularization factor for NMR logging data processing. This inversion method has no assumption about the white noise of a T2 echo train.
A new supplementary nonlinear equality constraint was introduced to optimize the solution of T2 distribution by explicitly taking into account the measured noise of a measured T2 echo train. An efficient iterative algorithm has been developed to solve the nonlinear optimization problem defined in the new inversion method. An initial-guess solution of the regularization factor was proposed for accelerating the searching process of the regularization factor.
The new inversion method has been verified with synthetic T2 echo train data and applied to process T2 echo train data of core samples of carbonate and Berea sandstone formations that are saturated with different fluids. This method has also been compared with conventional methods. The testing and comparison results show that: The optimal solution of T2 distribution from the new inversion method has a unique solution that is independent of the pre-selected values of regularization factor, so does the regularization factor. The optimal solutions T2 distribution and regularization factor will be convergent to their true solutions when the SNR of echo train data becomes sufficiently high. The computation cost for searching the optimal solutions of T2 distribution and regularization factor using the new nonlinear optimization algorithm is only a few iterations. The initial-guess solution of the regularization factor is more close to the solution determined from the S-curve method, which could be higher than the optimal solution of the regularization factor searched in the new inversion method.
The optimal solution of T2 distribution from the new inversion method has a unique solution that is independent of the pre-selected values of regularization factor, so does the regularization factor. The optimal solutions T2 distribution and regularization factor will be convergent to their true solutions when the SNR of echo train data becomes sufficiently high.
The computation cost for searching the optimal solutions of T2 distribution and regularization factor using the new nonlinear optimization algorithm is only a few iterations.
The initial-guess solution of the regularization factor is more close to the solution determined from the S-curve method, which could be higher than the optimal solution of the regularization factor searched in the new inversion method.
Nuclear magnetic resonance (NMR)
The North Sea Oil and Gas industry counts over 7,800 wells drilled. The industry is now entering an era of well abandonment and decommissioning. Current barrier verification for P&A requires appropriate pressure testing and includes surface and downhole monitoring.
Globally, Spectral Noise Logging (SNL) has been utilized in many thousands of cases to detect fluid movement behind completion tubulars and/or across a cement barriers.
In Nov 2017, full-scale verification tests were conducted at the International Research Institute of Stavanger (IRIS). These tests were conducted in a controlled environment to verify current technology thresholds. These showed the technique validated the cement barrier integrity during pressure tests and can diagnose channeling as low as 9 ml/min behind the casing. The threshold matrix for different cement defect versus pressure and flow rates allowed the usage of the technology to support the positive qualification of the barrier elements (
Utilizing a purpose-built test assembly of standard oilfield tubular and cement with fitted end caps, a series of pressure tests operations were conducted to identify the pressure and associate leak rates in conjunction with the SNL. The results clearly demonstrated that the logging tool can provide evidence of barrier verification over a wide range of well applications. Barrier qualification requires that three conditions are met; firstly, cement behind casing is in place and not displaying a micro-annulus or any form of fluid movement behind pipe. Secondly, that a cement plug holds pressure and there is also no fluid leak and finally natural shale barriers are active and create a sufficient barrier. Currently, technology is in its 10th generation, and since the IRIS tests have been used in many wells, covering both onshore and offshore oil and gas wells and wells in highly sensitive environmental areas. On each case the logging operations were used to verify well status before and after the barrier establishment via cement squeeze or section milling and, in several cases, clearly, demonstrate that the barrier status remained ineffective, hidden and further remedial work was required.
This paper discusses the downhole passive noise listening and its spectral analysis technique to prove the effective cement barriers are in place. The concept, methodology and its application which have been successfully tested via yard and field tests are presented in this paper.
Millions of workers are exposed to noise in the workplace every day and, when uncontrolled, noise exposure may cause permanent hearing loss. Research demonstrates exposure to certain chemicals, called ototoxicants, may cause hearing loss or balance problems, regardless of noise exposure. Noise is one of the harmful agents to health that is present in the various branches of economic activity. Hearing loss and tinnitus are among the most frequently reported complaints by workers exposed to occupational noise.
In both developed and developing countries, noise is regarded as the most common occupational hazard in various industries. The present study aimed to examine the effect of sound pressure level on serum cortisol concentration in three different times during the night shift. Will Daytime Occupational Noise Exposures Induce Nighttime Sleep Disturbance? Nighttime environmental noise affects sleep quality. However, the effects of daytime occupational noise remain unclear.
The US Occupational Safety and Health Administration, the National Institute for Occupational Safety and Health, the State of North Dakota, and the Bakken Basin Safety Consortium have signed an alliance to protect employees and promote safety and health in the oil and gas industry. The National Institute for Occupational Safety and Health is collaborating with partners in industry, government, academia, and labor and with other stakeholders to achieve successful and sustainable outcomes to improve worker safety and health across the oil and gas extraction industry. The tool, called the Field Analysis of Silica Tool, works with commercially available Fourier-transform infrared analyzers to determine a worker’s exposure to respirable crystalline silica dust, providing detailed results immediately following a worker’s shift. Millions of workers are exposed to noise in the workplace every day and, when uncontrolled, noise exposure may cause permanent hearing loss. Research demonstrates exposure to certain chemicals, called ototoxicants, may cause hearing loss or balance problems, regardless of noise exposure.
Although OSHA does not have a specific standard that covers working in hot environments, the Occupational Safety and Health Act requires places of employment that are "free from recognizable hazards that are causing or likely to cause death or serious harm." OSHA’s efforts to require employers to report occupational fatalities and certain injuries in a timely manner lack “sufficient guidance on how to detect and prevent underreporting,” the Department of Labor Office of Inspector General states in its semiannual report to Congress. To better protect workers exposed to respirable crystalline silica, OSHA has issued two new standards: one for construction and another for general industry and maritime. OSHA will begin enforcing most provisions of the standard for general industry and maritime on 23 June. Millions of workers are exposed to noise in the workplace every day and, when uncontrolled, noise exposure may cause permanent hearing loss.
A study published in the American Journal of Industrial Medicine finds that an injury serious enough to lead to at least a week off of work almost triples the combined risk of suicide and overdose death among women and increases the risk by 50% among men. A new retrospective cohort study has associated hydraulic fracturing sites with antenatal mental health issues such as anxiety and depression. This study incorporates previous learnings, as well as globally collected data, to develop a strategy that can be used to help implement an industry-specific mental health program. Research by Drexel University and the University of Colorado at Boulder suggests that imposing fees on energy producers that emit greenhouse gas could improve the health and financial well-being of the Rocky Mountain region. Mothers living near more-intense oil and gas development activity have a 40–70% higher chance of having children with congenital heart defects compared with those living in areas of less-intense activity, according to a new study.