Well Integrity Catastrophe Avoided Through Advanced Well Integrity and Reservoir Monitoring Analysis, a Case Study

Well integrity is one of the main challenges that are facing operators, finding the source of the well problem and isolating it before a catastrophic event occurs. This study demonstrates the power of integrating different reservoir monitoring and well integrity logs to evaluate well integrity, identify the underlying cause of the potential failure, and providing a potential corrective solution. Recently, some Injector/producer wells reported migration of injection fluids/gas into shallower sections, charging these formations and increasing the risk of compromised well integrity. Characterization of the well issues required integration of multi-detector pulsed-neutron, well integrity (multi finger caliper, multi-barrier corrosion, cement evaluation, and casing thickness measurements), high precision temperature logs and spectral noise logs. After data integration, detailed analysis was performed to specifically find the unique issues in each well and assess possible corrective actions. The integrated well integrity logs clearly showed different 9.625-inch and 13.375-inch casings leak points. The reservoir monitoring logs showed lateral and vertical gas and water movements across Wara, Tayarat, Rus, and Radhuma formations. Cement evaluation loges showed no primary cement behind the first barrier casing which was the root cause of the problem. Therefore, the proposed solution, was a cement squeeze. Post squeeze, re-logging occurred, validating zonal isolation and a return of a standard geothermal gradient across the Tayarat formation. Most importantly, the cement evaluation identified good bond from the squeeze point clear to surface, isolating all formations. All these wells were returned to service (injector/producer), daily annular pressure monitoring confirmed that no further pressure build up was seen. Kuwait Oil Company managed to avoid a catastrophic well integrity event on these wells and utilized the approach presented to take the proper corrective actions, and validate that the action taken resolved the initial well integrity issues. Consequently, the wells were returned to service, and the company avoided a costly high probability blowout.

High Definition Acoustic and Temperature Logging for the Diagnosis of Complex Annuli Leaks and Communication

Maintaining annuli integrity is critical for safe and optimized well operations. Monitoring of tubing casing annulus (TCA) and casing-casing annulus (CCA) pressures is mandatory as it gives a direct indication of possible seal or tubular failures that may lead to a negative impact on HSE or well production. In cases where the observed annuli pressures suggest leaks and possible communication between tubing and TCA or TCA and CCA, a comprehensive plan should be put in place to detect and evaluate the possible leak sources and paths that will allow for proper remedial actions. Logging techniques using spectral noise logging (SNL), and high precision temperature Logging (HPT) are one way to diagnose the source of a leak and communication path between 2 adjacent casings (for example TCA and CCA). The operation is performed by running the HPT and SNL log under shut in conditions to establish a base line, followed by logging under dynamic conditions. Dynamic conditions can include bleeding off the TCA pressure while all other annuli and tree valves are shut-in and injecting into the tubing-casing annulus while bleeding off the CCA. The dynamic passes aim to activate the leak points. The SNL and HPT will capture the corresponding temperature and Spectral noise events revealed by the fluid flow though the leak points. These are compared to the base line shut in logs. The SNL is run in stations and can capture noise generated by fluid movement in a wide range of strength (decibels) and frequency within a wide scanning radius, while HPT can capture minor temperature changes of 0.02 Deg F. The paper will discuss an example where the HPT and SNL were run along with a set of conventional sensors such as GR, CCL, and pressure in a HPHT gas well to diagnose leak points and a possible communication path between the TCA and CCA. The Logging operation was carried out rig-less with minimum intervention using wire line under the shut in and dynamic conditions. Spectral noise logging precisely captured the leak points and drew a clear picture of the casing integrity breaches in multiple points. The results of the diagnostics and evaluation will now be used to design the appropriate remedial actions required to restore the well to the desired condition for production.

Physical processes simulation in a precision device for liquid samples thermal cycling

An urgent task is the development of devices that provide a precision temperature change. The devices used in the real-time polymerase chain reaction method require not only repeated cyclic temperature changes with high accuracy, but also the temperature gradient minimization over the working fluid. In this article, the modeling of the working processes taking place in the thermal block of the device with the previously proposed thermohydraulic system, which ensures the temperature change together with the Peltier elements, is carried out. A mathematical model is formulated and a differential equation, boundary and initial conditions are substantiated. Numerical methods for solving the mathematical model in the Elcut software were applied. An experimental setup was developed and a study of heat exchange processes in the thermal block of a nucleic acid analyzer with a thermohydraulic system was carried out, confirming the adequacy of the developed mathematical model.

On how the mechanochemical and co-precipitation synthesis method changes the sensitivity and operating range of the Ba2Mg1-xEuxWO6 optical thermometer

The suitability of Ba2MgWO6 (BMW) double perovskite doped with Eu3+ for the construction of an optical thermometer was tested. It has been shown that by controlling the conditions of BMW synthesis, the sensitivity of the optical thermometer and the useful range of its work can be changed. Pure BMW and doped with Eu3+ samples were prepared using the mechano-chemical and co-precipitation methods. Both the absolute sensitivity and the relative sensitivity in relation to the synthesis route were estimated. The findings proved that the relative sensitivity can be modulated from 1.17%K−1 at 248 K, to 1.5%K−1 at 120 K for the co-precipitation and the mechanochemical samples, respectively. These spectacular results confirm the applicability of the Ba2MgWO6: Eu3+ for the novel luminescent sensors in high-precision temperature detection devices. The density-functional theory was applied to elucidate the origin of the host emission.

Non-Interventional and High-Precision Temperature Measurement Biochips for Long-Term Monitoring the Temperature Fluctuations of Individual Cells

Monitoring the thermal responses of individual cells to external stimuli is essential for studies of cell metabolism, organelle function, and drug screening. Fluorescent temperature probes are usually employed to measure the temperatures of individual cells; however, they have some unavoidable problems, such as, poor stability caused by their sensitivity to the chemical composition of the solution and the limitation in their measurement time due to the short fluorescence lifetime. Here, we demonstrate a stable, non-interventional, and high-precision temperature-measurement chip that can monitor the temperature fluctuations of individual cells subject to external stimuli and over a normal cell life cycle as long as several days. To improve the temperature resolution, we designed temperature sensors made of Pd–Cr thin-film thermocouples, a freestanding Si3N4 platform, and a dual-temperature control system. Our experimental results confirm the feasibility of using this cellular temperature-measurement chip to detect local temperature fluctuations of individual cells that are 0.3–1.5 K higher than the ambient temperature for HeLa cells in different proliferation cycles. In the future, we plan to integrate this chip with other single-cell technologies and apply it to research related to cellular heat-stress response.

Sustained Annulus Pressure Diagnostics in Offshore Wells by Multisensory Spectral Acoustics

The monitoring of sustainable annulus pressure (SAP) in offshore wells plays an important role in the development of an oil reservoir with a massive gas cap. The method of spectral noise logging and high-precision temperature logging used to identify SAP source presented in work (Shtun 2020) proved to be good in determining the intervals of gas movement, however, the method is limited in answers. The most significant limitation of the spectral noise logging method is associated with the impossibility based on power spectrum to distinguish the zones of gas flow in the annular space and gas inflow zones from reservoir contributing SAP. This information is critical for proper workover planning to eliminate SAP. This limitation relates to the fact that the amplitude and frequency of the resulting signal depend on not only the aperture of space fluid flow through and depend on the turbulence of the fluid flow. The paper describes a novel technology of multisensory passive acoustics of radial location that is designed to differentiate far and near acoustic sources in wells to accurately define the sources of SAP. The results of laboratory and field cases in offshore oil wells were presented in this paper as well as the comparison between single sensor spectral noise logging and multisensory passive acoustics of radial location answers was given at the end of the paper based on real case studies. As shown in the paper the described technology provides a more accurate determination of the source of SAP and the geometry of fluid movement in the near-wellbore zone.