Total well system integrity and ‘the containment and prevention of the escape of fluids’ (ISO TS 16530-2) remains one of the biggest challenges Middle East operators face today. The Middle East has been the world’s most prolific oil-producing region for decades with one of the largest populations of ‘hard-working’ aging wells – many of which operate continuously in extreme environmental conditions. More than 70% of the ~800 Middle East platforms and associated well-stock are more than 25 years old.   Not surprisingly, Middle East operators are facing a constant challenge to manage corrosion and sustained annulus pressure [SAP] in their well systems, and are always on the lookout for new innovations to help. This article will provide examples of two such innovations – corrosion surveillance in chrome-based tubulars, and addressing SAP. To celebrate, TGT invited employees, customers, and business partners to an evening which relived the company’s scientific breakthroughs using acoustic, thermal and electromagnetic energy to reveal unique answers within and beyond the well bore.   Dr. Arthur Aslanyan, TGT’s Co-Founder commented, “It gave me great pride to attend the event and celebrate the company's 20th anniversary. We have come a long way since we first started the business. We are very excited about our future as the company continues to thrive”.   The event was attended by Saad Bargach, TGT Chairman and LimeRock Partners -private equity investors.   Hegazi continued, “Looking to our future, TGT is releasing several lines of new technologies and applications in coming months to further cement our position as pioneers of Through-Barrier Diagnostics. Our patent technology developments coupled with our unrivalled Geoscience organisation and global footprint, provide unique and reliable diagnostic services to our customers. This has been key in maintaining our fast growth trend and industry reputation. I am confident this foundation along with our excellent teams, will continue to fuel our growth for many years to come. Overcoming chrome As Middle East well conditions become more corrosive, so operators have looked to more corrosion resistant materials in the completion process, leading to a rise in chrome and nickel content in steel tubulars. However, one unintended side effect is the decrease in the effectiveness of ordinary electromagnetic [EM] well and pipe inspection systems and the tracking of corrosion in multiple barriers.   The increase in chrome and decrease in ferrous content causes EM signals to decay too quickly for such systems to be truly effective in monitoring corrosion and evaluating pipe thickness or metal loss in casing strings. So while corrosion resistance may have increased, there is now a potential information vacuum.   TGT, the market leader in through-barrier diagnostic systems, has developed a new multi-barrier integrity diagnostics system – EmPulse®. The system quantitatively determines individual wall thickness in up to four concentric tubulars, ensuring long-term well performance in the most challenging high-chromium production environments.   The EmPulse system incorporates ‘ultra-fast’ sensor technology, three independent sensors, and ‘time-domain’ measurement techniques to capture EM signals rapidly and accurately in a wide range of pipe materials before the signals decay.   In three recent Middle East deployments – an operator witnessed ‘yard test’ in 28% chrome pipe with built-in mechanical defects, and two live wells – the EmPulse system correctly identified man-made defects and quantitatively determined the individual tubular thickness.   This successful validation in high-chromium tubulars brings important reassurances for Middle East operators in protecting well system integrity – providing accurate corrosion information and addressing a crucial information gap. The case of sustained annulus pressure [SAP] Figure 2: Spectral diagnostics survey revealing source of SAP behind casing at X540m where the cement map indicates ‘good cement’. Another major challenge to Middle East well system integrity is that of SAP – pressure in any well annulus that rebuilds when bled down.   Reasons for SAP can vary but are often due to weaknesses in the cement during completion; cement degradation due to thermal and pressure loading; leaking tubing connections or wellhead seals; and corrosion. According to a 2013 SPE webinar on wellbore integrity [Paul Hopmans], out of ~1.8 million wells worldwide, a staggering 35% have SAP, with many Middle East fields facing varying levels.   Wells with SAP need to be carefully managed and production can be adversely affected or halted. SAP can also cause further damage to the well system, potentially resulting in the failure of the production casing or outer casing strings, and well blowouts.   While many operators are addressing SAP through new well designs and barriers, and better quality control over cementing – with existing wells they are having to rely on surface data – fluid sampling and bleed-off/build-up data, for example – to investigate the problem downhole.   There is also the challenge of being able to locate leaks and unwanted flowpaths behind multiple barriers, not clearly seen by conventional temperature and ordinary noise logs.   TGT’s spectral diagnostics technology locates leaks and flowpaths throughout the well system by tracking fluid movement behind pipes within several casing strings.   Spectral diagnostics utilise high-fidelity downhole sound recording systems to capture the frequency and amplitude of acoustic energy generated by liquids or gas moving through integrity breaches and restrictions such as cement channels, faulty seals and casing leaks. When coupled with surface data, the information can narrow down the range of remedial options available, and target leak repairs.   Spectral diagnostics include fast, high-precision temperature measurements to locate integrity breaches throughout the well system. High-precision temperature sensors respond more quickly than conventional sensors to the localised thermal changes caused by integrity failures, complementing acoustic measurements by providing a visual confirmation of leaks and flowpaths.   While conventional production logging measurements typically assess only high-rate first-barrier failures – the high-fidelity recording, sensitivity and clarity of spectral diagnostics enables the tracking of even low-rate leaks at very early stages behind multiple barriers, enabling timely intervention and prolonging well life. In the following example [figure 2], a water injector well experienced sustained B-annulus pressure, although the build-up rate did not exceed one bar a day – indicating a low-rate leak.   A cement bond survey indicated good cement bonding below X500m, and poor bonding above. Poor cement bonding is likely to provide flowpaths for fluid movement behind casing. Unfortunately, cement bond log indications of ‘good bonding’ don’t guarantee annulus integrity. Flowpaths can exist that remain unnoticed by the cement bond log.   A survey utilising TGT’s spectral diagnostics system was conducted and revealed fluid flow from the reservoir around X540m and channelling up the annulus through the ‘good bonding’ area.   The frequency spectrum pattern correlated with reservoir permeability and fluid-type profiles, suggesting gas being produced from these formations. The operator used the information to target a cement squeeze operation at the desired location in the well – restoring B-annulus integrity and eliminating the SAP. Evolving challenges, new technologies  As Middle East operators continue to face well integrity challenges, gaining a deeper insight into both well and reservoir dynamics is vital. Advanced well diagnostics systems are now available to allow this to be achieved.

Healthy Wells  Proactive integrity management is a key focus area for exploration and production operators, and rightly so. Well integrity is fundamental to enabling maximum well system performance, and minimising cost and risk for the operator.   A well is usually delivered intact when new but issues like leaking connections or poor cement isolation can exist from the start and these of course need immediate and regular integrity diagnostics surveillance.   Then, as the well becomes exposed to harsh working conditions underground over many years, integrity breaches will occur, with these needing diagnosis and addressing early on. Inside the tubing diagnostics Through-barrier diagnostic systems – a capability TGT scientists and engineers have been pioneering for years – are vital for this task as they can evaluate most of the well system from inside the tubing.   Through-barrier diagnostic systems sense dynamic well behaviour and certain well properties behind well barriers – and consequently evaluate the condition and performance of the well system from inside the tubing. Such systems can determine the wall thickness of individual tubulars in up to four concentric pipe strings to track corrosion in each pipe. They can also locate fluid movement behind the pipe – essential in determining annulus integrity or locating barrier leaks.   Through-barrier diagnostic systems cleverly harness heat, acoustic and electromagnetic [EM] energy to perform certain measurements downhole and engage sophisticated processing and modelling to transform these measurements into insightful and useable answers.   It’s important, however, that through-barrier diagnostics keep up with current well integrity challenges. High-chrome tubulars are increasingly prevalent in the Middle East as a means of combatting corrosion but also challenging for ordinary EM well inspection systems to operate, due to a decrease in ferrous content and conventional EM signals decaying too quickly. High chrome deployments With this in mind, TGT recently conducted three successful high-chrome deployments with its EmPulse well inspection system – one a yard test with a 28% chrome pipe with built-in mechanical defects, and the two others live wells with high hydrogen sulphide and 28% chrome tubulars.   In the first case, the high-speed EM sensor technology and ‘time-domain’ measuring techniques correctly identified man-made defects and in the two live wells they recorded the status of three concentric well barriers.   Another well integrity challenge is cementing – particularly in deeper and longer reach wells – where cementing techniques and sealing abilities are being pushed to the limit. In such cases, ‘spectral diagnostics’ is a technology that tracks fluid movement behind pipes within several casing strings and identifies leaks and flowpaths.   Key to spectral diagnostics is its ability to utilise high-fidelity downhole sound analysis systems to capture the frequency and amplitude of acoustic energy generated by liquids or gas moving through integrity breaches and restrictions. Understanding well integrity While the meaning of ‘well integrity’ is often debated, it has one unifying principle – that of containment – ensuring that the right fluids connect safely and productively via the wellbore to surface, and that they don’t stray along unwanted flowpaths either inside, or worse still outside the well system.   Since most integrity failures happen behind tubing or casing, it’s incumbent upon through-barrier diagnostics to deliver the well system insights that Middle East operators need to ensure safe and productive operations. It’s reassuring to know that technologies are evolving to meet these challenges

Well systems vary in complexity and cost, but they all share one fundamental duty – to transport pressurised fluids between the subsurface and surface safely, productively and profitably. And they must do so unfailingly, whilst exposed to extreme working conditions for many years, often decades.   This article will look at some of the key issues surrounding integrity management, including threats to well system integrity such as corrosion and new diagnostic strategies that are addressing them in the Middle East.   Maintaining the integrity of a well system is critical for its long-term future. Integrity failures vary in severity but in most cases can prevent the well system from functioning properly. An article by R.J. Davies contains integrity statistics from 25 different studies that reveal failure proportions around the world from 2% to 75% in more than 380,000 wells. Other frequently quoted statistics refer to alarming failure proportions in major producing areas such as 45% in the Gulf of Mexico and 34% in the UK North Sea. Integrity failures at these levels would never be tolerated by other industries, such as the airline or chemical processing sectors – so we clearly have a responsibility to improve integrity performance in ours.   Technically, well integrity depends on the collective performance of multiple ‘barriers’ that are designed to ensure that the right well fluids consistently travel to and from the right places – without compromise. Such barriers include steel tubulars, cement, valves, wellheads and a plethora of other components that form and protect precise fluid flowpaths.   To achieve this, well barriers need to have two fundamental properties – they need to be in good mechanical ‘condition’, and they need to ‘seal’. Surprisingly, despite the intimate relationship between these properties, satisfying one doesn’t imply that the other is also satisfied. A barrier may appear to be in good condition, but may not be sealing, or a barrier may be in poor condition yet still be sealing. The latter condition may be temporarily fortuitous, but poor barrier condition will eventually lead to seal failure.   This strangely inconsistent relationship between condition and seal becomes more pronounced when we try to evaluate each properly using industry-accepted diagnostic methods.   Take acoustic ‘cement bond’ or imaging techniques – used for decades to infer the success of a ‘cement job’ and annulus integrity. Advanced ultrasound scanning systems can reliably assess the strength and annular extent of the cement but cannot confirm if the cement is sealing. Similarly, multifingered calipers provide an accurate means of measuring the internal diameter of ‘primary tubulars’ and is often used to infer ‘wall thickness’ and condition – but this assumes that the outside surface diameter is ‘nominal’ or unscathed, and this may not be the case. Other examples of imperfect diagnostic techniques include using stand-alone temperature measurements or ‘spinners’ to locate primary tubular leaks. These work in certain circumstances, but not all. Effective surveillance These factors point to the need to follow three key surveillance principles in the quest for effective integrity management: firstly, evaluate both the condition and sealing performance of critical well barriers; secondly, monitor these properties routinely and proactively; finally, use the right diagnostic system for the task.   One area where these principles particularly apply is in the surveillance of ‘tubular condition’ – sometimes referred to as ‘tube integrity’ or ‘corrosion’ monitoring.   The most prolific barriers in the well system and the backbone of its integrity are the steel tubulars, casings and cement that fuse together with the subsurface to form the well system. Often operating in extreme conditions, tubulars must be in good condition to ensure containment and provide mechanical support. But many factors conspire against the integrity of the tubes making integrity management extremely challenging.   The first is accessibility. Most well tubulars exist behind the primary tubing, making them difficult to access for remediation. The second is surveillance. The hidden nature of outer casings means that corrosion and even failure is particularly insidious and challenging to detect. The third is that whilst steel barriers are strong, they are vulnerable to one fundamental weakness – they can corrode. The fourth is the environment within which tubulars need to perform. Heat, pressure, mechanical loading, aquifers and corrosive fluids such as carbon dioxide, hydrogen sulphide (H2S) and brine play havoc with steel. Lastly, the fifth factor is time. Well systems are expected to endure extreme conditions for decades. Aquifer issues The Middle East has more than its fair share of corrosion challenges. Amplifying the factors listed above are region-wide aquifers, such as the Umm er Radhuma, which inevitably corrode well systems from the outside, and high-H2S production, which can corrode from the inside. Operators in the region use several methods to combat this, including chrome completions that are resistant to attack. Some Middle East operators are also leading the way in adopting at least two of the surveillance principles above – namely, implementing proactive tube integrity surveillance, and using the most appropriate diagnostic system for the task.   TGT is a specialist in ‘through-barrier diagnostics’ for the oil and gas industry and is at the forefront of tube integrity surveillance. The company has designed and engineered a diagnostic system which harnesses electromagnetic [EM] energy to assess the condition of multiple tubulars from within the production tubing. This in-house design combines features with advanced 4D modelling to deliver impressive accuracy across multiple barriers.   Notably, the system also works in chrome completions – prolific in the Middle East and a hostile environment for ordinary EM devices. The system is being used across the region to evaluate existing corrosion issues, and proactively to track and predict tube failures before they happen.   Maintaining well system integrity is a persistent challenge, but with the correct approach in evaluating barrier condition and seal proactively, and by using reliable diagnostic systems, operators can maintain well performance – without compromise.

Creating reservoir flow profiles can enable better well and field management decisions. A completed well is a sophisticated industrial-scale plumbing system, designed to transport fluids between subsurface reservoirs and the surface safely, productively and profitably. Injectors transport fluids one way, and producers transport more valuable fluids the other. Well system fusion Before the insertion of this grand plumbing scheme into the earth, the targeted subsurface reservoir and the fluids contained within it existed for millennia in a state of relative equilibrium. However, when the human-made tubulars, cement sheath and other well completion elements were “fused” with the subsurface by the well construction processes, this stasis was dramatically transformed into a complex and turbulent dynamic state.   This fusion between the human-made materials of the well completion and the natural materials of the earth, together with the dynamic interplay that now exists between the two, is what TGT Oilfield Services calls the “total well system.”   The well system includes that previously elusive volume of earth that exists beyond the wellbore, in the outer periphery of the well completion and the cement sheath that surrounds it—the so-called “well-to-reservoir interface.” Understanding the behavior of fluids here, and specifically the “flow” of fluids, is crucial to understanding the productive behavior of the entire well system. This is one reason why TGT Oilfield Services developed through-barrier diagnostics, which reveal flow behavior throughout the well system, from the wellbore through the completion and to its outer extremities where it connects intimately with the reservoir. An imperfect world In a perfect world, the well completion behaves according to its design and transports the right fluids to and from the right place in the subsurface. Moreover, in the same perfect world, the reservoir surrenders or receives the right fluids, and the total well system delivers safely, productively and profitably according to plan.   However, imperfections corrupt this ideal relationship and forces conspire to undermine the system. Imperfect cement seals, degraded packers, worn out valves, corroded pipe, near wellbore fractures and other barrier failures collude to open unwanted flow paths throughout the well system. As a result, essential fluids are diverted, sustained annulus pressures can dangerously manifest and, ultimately, producers or injectors will not behave as expected or underperform. Water destination A classic example of this occurs in injector wells. Petroleum and reservoir engineers determine that if water is injected at a particular pressure, then subsurface target zones will receive a certain volume of water over time. If the predicted flow rate is not observed, then either something is wrong with the assumptions and calculations or something is wrong with the well system—or both. Even worse, the predicted flow rate might be within range, but the water might not be reaching the target. The latter scenario is particularly insidious because it may be weeks, months or longer before an alarm is raised.   TGT has diagnosed thousands of injector wells and, in the majority of cases, has revealed unwanted flow paths behind the production casing, under- and overperforming target zones, and “thief zones” that effectively “steal” water from its intended destination.   Consider the injection well case shown in Figure 1. Conventional borehole flow diagnostics using production logging techniques (PLTs) tell the operator that most of the injected water is reaching the top half of the target reservoir unit (A3), and the rest is entering the lower half (far right track labeled “borehole flow profile”). Injection well case However, through-barrier spectral diagnostics by TGT reveal the true picture of what is happening with the well system. In reality, only 25% of the injected water is entering the target reservoir unit. The rest is channeling upward to a shallower unit (A2) from 210.3 m (690 ft) to 158.5 m (520 ft), probably though an imperfect cement sheath behind casing. A smaller amount is channeling downward.   This is a serious issue from both a well and reservoir management perspective. Not only is the target reservoir not receiving enough water to fulfill the field injection strategy, but 75% of the injected water is being wasted and potentially causing water breakthrough issues at other wells, compounding the loss. This essential information directly impacts well performance and potentially fieldwide management decisions. Harnessing acoustic, thermal energy TGT’s spectral diagnostics harness acoustic and thermal energy to locate and quantify fluid flow behind well barriers, thereby providing a complete picture of flow dynamics and pathways throughout the well system. High-fidelity sound recordings and processing technology deployed downhole locate flow activity by capturing and analyzing the characteristics of sound energy generated by pressurized fluid passing through well system restrictions, such as cement channels and reservoir entry points.   The position and relative intensity of the resulting spectral signature indicate the precise locations of flow activity (see the middle track of Figure 1 labeled “spectral injection”). This information is then used together with other well system data to guide a powerful and unique flow modeling engine that transforms precise thermal profiles into flow rates. The result is a behind-casing reservoir flow profile, which can be used in combination with the borehole flow profile to enable better well management and field management decisions (see right-hand track labeled “reservoir flow profile”).   Well barrier imperfections exist in all well types, so similar “unwanted flow path” scenarios exist in production wells too. Water source  The case shown in Figure 2 is a deviated production well exhibiting a very high water cut of greater than 90%. Identifying the source of high water cut is one of the most urgent priorities for petroleum and reservoir engineers to resolve.   Whereas the PLT-derived borehole flow profile can only measure flow entering the wellbore in front of the perforated interval (A2), the spectral signature map indicates significant flow activity behind casing at several other producing intervals, namely A3, A4 and A5, and to a lesser extent at A1. Given that these intervals are known to be water-filled, the operator can confidently conclude that more than 60% of the produced water is coming from these zones. Knowing the exact locations of the source, the operator can take appropriate action to seal off the unwanted flow paths. Deviated production well exhibiting a very high water cut of greater than 90% Good bond, bad seal In the case study, the operator concluded that water from these zones was channeling through an imperfect cement sheath. Even though the azimuthal cement map and cement bond log indicated that the cement sheath had good mechanical coverage and a good bond with the casing, the cement was not providing a hydraulic seal. This specific aspect underlines the importance of verifying both barrier condition and barrier sealing performance when deciphering flow dynamics around the well system and eliminating unwanted flow. Completing the picture Conventional technology, such as PLTs, helps operators understand flow dynamics within the wellbore. However, this information does not always align with what is happening beyond the wellbore—beyond casing and cement at the reservoir interface. Evaluating the well system with through-barrier diagnostics is the only way to understand what is happening in the well system. Armed with a complete picture, the operator can confidently make better decisions to ensure the well system delivers the right fluids to the right place, safely and profitably for the entire productive life of the well.

New fracture flow diagnostics help operators elevate fracture performance  In recent years, the Permian basin is been the most prolific shale play in the US. Production in this area increased to 3.8 million barrels by 2019, representing almost 70% of the whole US production growth from 2011 to 2019 according to International Energy Agency (IEA). The impressive aspect of this achievement is that the growth has not stopped. On the contrary, the Permian is expected to continue growing and is estimated to achieve up to 5.8 million barrels by the end of 2023.   Such impressive growth doesn’t come easy. Significant advances in drilling, completing and multi-stage fracturing will continue to drive production increases. But evaluating the performance of fracturing programmes and the wells they deliver is key to optimising resources and ensuring maximum return on investment. Conventional diagnostics [such as production logging tools or ‘PLT’s’] can’t provide all the insights required to ensure the operator is achieving the best returns. This article focuses on the challenges faced when assessing unconventional reservoirs in terms of production, and features a new diagnostic capability introduced by TGT to evaluate the flow performance of hydraulically fractured wells, stage-by-stage. The new diagnostic product is aptly called ‘Fracture Flow’.   Operators have been drilling aggressively and pushing the boundaries of hydraulic fracturing beyond conventional standards compared to other plays. The drilled length of lateral sections has been constantly boosted, adding more footage as well as more production stages. The ultimate objective is to penetrate deep into the target formation increasing the area of contact with the specific reservoir or formation making the well, its completion and the reservoir one dynamic production system.   Champions of this approach include a Houston-based operator that recently drilled such a well at the Wolfcamp. The completion included a lateral section of more than 17,900 ft running through the Spaberry formation. The completed well had a total measured depth exceeding 24,500 ft with a customised completion design and fracking treatment. The completion included more than 50-stages and sand was pumped along more than 2,200 ft of reservoir to increase the well productivity.   These extended laterals have been engineered to optimise production performance and leverage improvements in drilling, fracking treatments and completion designs. The operators have overcome the number of well construction challenges and have quickly moved up a steep learning curve.   Like the challenges encountered with well construction, the Permian basin faces its own challenges. Following such an extensive multistage hydraulic fracturing programme, the wells are brought onstream at high initial production rates. But most of these extended-lateral producers tend to decline dramatically over a very short period. To help combat this challenge, and many others, TGT has developed a number of application-specific diagnostic products using its ‘True Flow System’ to quantitively evaluate flow dynamics throughout the entire well system – from reservoir to the wellbore, and the dynamic interplay between the two.   When talking about a hydraulic fracturing job, we all know the importance of the programme design prior to execution. During this phase, sophisticated software is utilised to model and optimise the fracturing programme, taking into consideration multiple variables. These variables include formation properties, lithology, depth, mechanical stresses and other parameters that can affect the final outcome. Another important consideration is the formulation of the hydraulic fracturing fluid. This fluid is normally comprised of sand (or proppant), gels (foam or sleek-water) and additives that are pumped downhole following the job design to prop open the induced fractures and maximise the extension of the fracture in terms of length, height and aperture as well as the integrity of the fractured conduit itself, so hydrocarbons can flow unabated.   TGT’s diagnostic ‘Fracture Flow’ product is able to locate and evaluate fracture inflows and quantify inflow profiles in hydraulically fractured wells. The product is delivered by our analysts using the ‘True Flow System’, which combines several technology platforms – Chorus (acoustic), Cascade (thermal), Indigo (multisense) and Maxim (digital workspace), to acquire, interrogate and analyse the acoustic spectra and temperature changes generated by the hydrocarbons or any other fluid flowing from the reservoir through active fractures and into the completion. This diagnostic capability goes beyond conventional flow measurement techniques that generally stop sensing at the wellbore and are therefore unable to quantify flow within the reservoir itself.   The Fracture Flow product extract shown in figure-1 represents the diagnosis of a hydraulically fractured oil producer with >80 degrees deviation. The reservoir has a gross thickness of approximately 1,200 ft and is fully cased. To celebrate, TGT invited employees, customers, and business partners to an evening which relived the company’s scientific breakthroughs using acoustic, thermal and electromagnetic energy to reveal unique answers within and beyond the well bore.   Dr. Arthur Aslanyan, TGT’s Co-Founder commented, “It gave me great pride to attend the event and celebrate the company's 20th anniversary. We have come a long way since we first started the business. We are very excited about our future as the company continues to thrive”.   The event was attended by Saad Bargach, TGT Chairman and LimeRock Partners -private equity investors.   Hegazi continued, “Looking to our future, TGT is releasing several lines of new technologies and applications in coming months to further cement our position as pioneers of Through-Barrier Diagnostics. Our patent technology developments coupled with our unrivalled Geoscience organisation and global footprint, provide unique and reliable diagnostic services to our customers. This has been key in maintaining our fast growth trend and industry reputation. I am confident this foundation along with our excellent teams, will continue to fuel our growth for many years to come. Figure-1 ‘Fracture Flow’ diagnostics compare fractured intervals [blue] to main producing intervals [green] at different choke sizes in order to evaluate the true effectiveness of hydraulic fracturing programmes and maximise well performance The operator’s objectives in this case were to evaluate the post-fracture performance of three zones, and in particular:   - Compare the effectiveness of fractured stages by assessing the production contribution from each fractured interval - Identify crossflow or behind-casing communication - Increase production efficiency by identifying the optimum production choke for this well system.   The results revealed by the Fracture Flow analysis clearly revealed that the fractured intervals (figure-1 – blue coding) were not contributing fully to production in their entirety. Furthermore, it identified exactly the active zones and where the main production was coming from (figure-1 green coding). Fracture Flow revealed that only 62%, 59% and 56% of each zone was actually producing at the outset.   The Fracture Flow analysis also indicated that there were no crossflows among the three zones which was another key finding from an integrity perspective.   Thirdly, the Fracture Flow diagnostic programme helped to determine the optimal choke size required to ensure that the fractured zones were contributing at maximum rate.   TGT work in close collaboration with operators using Fracture Flow to help them reach their frac evaluation objectives; locate effective fracture inflows; quantify inflow profiles; and assess the effectiveness of fracture programmes, helping to optimise future programmes and maximise return on investment.   TGT is an international diagnostics company that specialises in ‘through-barrier diagnostics’ for the oilfield. Our Houston-based operation provides unique ‘True Flow’ and ‘True Integrity’ diagnostics to operators throughout the United States, including the Permian. We are also working actively in deep water Gulf of Mexico, Latin America and other major basins around the globe. Our diagnostics help operators make better decisions so they can manage wells safely, productively and profitably. tgtdiagnostics.com

New ideas that reveal a greater truth When oil prices fell in 2014 exploration and production (E&P) companies were forced to tighten capital budgets, reduce activity levels and drive down costs. The ensuing stampede to cost reduction hit upstream oilfield service companies extremely hard.   Today, with the oil price stablising, operators are more inclined to push their assets harder to produce more. However, when budgets were slashed, planned maintenance and workovers were amongst the first to be cut or deferred, while still treading the line not to compromise on safety. Securing asset reliability is still a top priority, ensuring that wells perform at full capacity while safeguarding life and the environment.   “Wells need to perform better and last longer. Operators need to elevate well performance and need the ingenuity of oilfield service companies to do this more effectively”, comments Mohamed Hegazi, Chief Executive Officer, TGT. “In today’s economic climate we have an obligation to challenge the old way of thinking by being bold and innovative so that customers can capture more value and address well performance challenges more readily.”   For all asset managers, a key area of vulnerability lies in the happenings thousands of meters away from the surface—downhole. A new way of thinking Like a giant industrial plumbing system fused into the earth, wells are built using a fantastically complex assembly of tubes, barriers and cement, most of which exist around a central producing conduit. Their sole purpose being to transport valuable fluids safely, productively and profitably.   Unfortunately, we live in an imperfect world where natural forces conspire to undermine the perfect functioning of the well, and despite the ingenuity of man, the well will inevitably misbehave or fail. Naturally, the industry is obsessed with ‘wells’ and ‘reservoirs’. But conventional definitions and diagnostics of ‘the well’ tend to isolate the well completion from the reservoir, and yet the two are so inextricably linked they should never be separated – they work as one.   A new definition of the well is therefore needed. One that recognises the performance attributes of the completion and the reservoir it connects to, the interplay between the two, and the dynamics of the entire system. In fact, what we are dealing with isn’t just ‘a well’ – it’s ‘a well system’.   But that’s not enough. We also need to recognise the two most vital performance factors of all well systems—flow and integrity.   ‘Flow’ is about the right fluids connecting to the right places, and ‘integrity’ makes sure that happens—without compromise. So, managing well system performance effectively means managing flow and integrity – and not much else matters. The two most vital performance factors of all well systems, flow and integrity “Diagnosing well system performance is challenging. Flow and integrity issues can exist anywhere within the well system; beyond the wellbore, behind multiple casings to the outer reaches of the well system, and in the reservoir itself—a place virtually impossible to deploy diagnostic sensors”, adds Mohamed.   Conventional diagnostics can’t provide all the answers because either they don’t look far enough, or measure the right things—they don’t look at the big picture. Rogue happenings, such as active thief zones, cross-flow or the source of sustained annulus pressure lurk behind barriers and wouldn’t be diagnosed with traditional techniques. A new category is born Flow and integrity, and therefore well system performance, can only be properly understood and managed by assessing more than the inner workings of the wellbore. This concept is the foundation of a new and important oilfield category, applicable to all wells—through-barrier diagnostics.   Diagnostic tools that ‘sense through barriers’ have existed for decades and overlap into this category, but apart from a few exceptions these have been chiefly concerned with investigating reservoir properties, such as matrix and fluid parameters, or evaluating cement.   Acknowledging and advancing through barrier diagnostics as a new category allows us to look at the well system in a far more holistic and uncompromising way. Seeing through multiple barriers from the wellbore into the reservoir and everything in between reveals more than ever before. Viewing the well system in its entirety provides operators with a more complete picture of the goings on, both flow and integrity related. And equipped with better insights, operators are much better placed to make the right decisions to keep the entire system working harder. Diagnostic tools vs. diagnostic systems Maintaining safe, productive and profitable operations means that all well systems at some point will require diagnostic intervention, either for routine monitoring or to target a specific issue.   When it comes to diagnostics, ‘tools’ tend to dominate oilfield conversations, technical forums and procurement practices, and the operational focus tends to be on ‘running the tool in the well’. If a well system is experiencing unexpected sand flow, ineffective stimulation or fracturing, or sustained annulus pressure, the operator commissions a service company to deploy a certain tool in the belief that the tool itself will provide all the answers. But the reality is not that simple.   In isolation, the tool gives raw data and measurements, but revealing the truth about the well system requires more than the tool. The tool’s sensitivity and accuracy is extremely important, but many other factors beyond the tool contribute to the overall diagnostic result.   The synergy happens in all facets of the service, not just the tool; the diagnostic programme that activates the well, and the method for acquiring the data, the processing and modelling to refine and expand raw data, and the expertise in analysis and interpretation, all play a vital part. The results and insights materialise from the combined effort of all these factors—an entire ‘diagnostic system’, curated and applied by human experts.   There is no doubt that advancing diagnostics to deal with today’s challenges means evolving from tools to diagnostic systems on all fronts. But we need to go one step further. From systems come products When a well is exhibiting problems, what the operator ultimately needs is answers. Obviously, there’s an interest in making sure that the right diagnostic system is utilised, but the purchasing decision should be ultimately based on the clarity and completeness of the answer, because this is the final ‘product’ in the diagnostic workflow.   Consider the case where a well suddenly exhibits flow issues, such as a dramatic increase in water-cut, or complex integrity issues such as sustained pressure in the C-annulus. Then the operator is more concerned about getting an answer it can trust to solve these issues, not what tool or system to use.   “An application-led ‘products’ approach versus a traditional ‘tools’ approach allows for improved product selection and commercial flexibility, benefiting operators on both counts. Operators certainly appreciate technology but are ultimately seeking diagnostic answers that can help them make better decisions”, summarises Mohamed alluding to the approach TGT has adopted.   He adds, “A mechanism should be adopted where simpler products, such as diagnosing wellbore flow, that demand fewer resources and less innovation command a lower price. Whereas more complex products—like multi-barrier diagnostics, that have years of research and development behind them, demand more extensive resources, and ultimately deliver more value, naturally command a higher price.” A bright future The old thinking can’t answer today’s new challenges. As well systems become older and more complex, managing performance will remain a priority and continue to task the industry. That’s why we need to innovate on all levels. Not just by building better tools, but by creating better diagnostic systems and recognising the experts that empower them. We need to acknowledge the dual importance of flow and integrity as the key enablers for asset performance, and the criticality of through-barrier diagnostics as the only means to see the true picture. And last not least, we need to adopt a product-led approach to procurement, where the answer is king, and not the tool. Do all that and the future looks bright.

TGT’s 11th Student Mathematical Modelling and Information Technologies (SMIT) conference was held on 25-26 April at our Technology Centre, Kazan.   SMIT provides top engineering students with the opportunity to engage with leading industry experts. The conference mainly focuses on ‘best practice’ for modelling physical processes and the implementation of new mathematical signal processing techniques used in the oil and gas sector plus other industries.   University students registered their interest by submitting an abstract on www.smit-conference.com. Abstracts were reviewed by a panel of academic society representatives and industry professionals. At the conference each participant was invited to deliver their 15-minute presentation. The best work was published in peer-reviewed scientific journals which is recognised by the State Commission for Academic Degrees and Titles. "We are an innovative company, constantly striving to advance our well flow and well integrity services. Attracting, developing and retaining top talent is critical to our culture and future”, comments Maksim Gladkiy, Deputy Managing Director, TGT Oilfield Services Technology Centre.   “Together with our partners, our goal is to help young talented students to be discovered and provide a platform for them to launch their careers”, adds Maksim. “SMIT provides an excellent opportunity for participants to share experiences and ideas; and to be reviewed by experts in a real-life industrial application.” adds Maksim.

The company’s vision and motivator is the thirst for a greater knowledge of the well system, which combines the well completion and reservoir TGT Oilfield Services, the market leader in through-barrier diagnostics for the oilfield, has grown year-on-year even during the downturn and the company expects to see an improvement in both activity levels and pricing as the industry stabilises further.   "Despite the drop in oil price, the demand for TGT diagnostic services grew significantly. Our focus on technology and applications that diagnose the performance and integrity of existing wells is exactly what our clients needed during the tough budget years.   "We expect that need to continue. We protect our market share and growth by continuing to fund technology development despite the market climate. Customers recognise the depth of our technical and sub surface knowledge, which has been built up over the last 20 years," says Maged Yassin, business unit manager, TGT Saudi Arabia. The company’s vision and motivator is the thirst for a greater knowledge of the well system, which combines the well completion and reservoir. This speaks for itself when one considers that more than a third of its headcount is dedicated to R&D and technology development, says Yassin.   Recently, TGT migrated its sensors to a custom-built ‘low-noise’ hardware – Indigo – designed to operate at ‘low noise’ so not to interfere with its acoustic-based ‘spectral’ and electromagnetic-based ‘EmPulse’ diagnostic systems.   Additionally, the company added a real-time capability to its fleet of through-barrier diagnostic systems. The new real-time technology enables well data to be viewed and analysed at surface during the execution of well diagnostic programmes without compromising on measurement fidelity. "We never stop, continuously improving our services and our offerings," says Yassin.   TGT provides a wide range of through-barrier diagnostics. Patented technologies are deployed on any conveyance and sense beyond the well bore to answer multiple reservoir flow and well integrity questions. The company offers these services in Saudi Arabia via in-country assets, geoscience and advanced interpretation as well as business development and field operations. TGT was founded on research and development. "Our technologies include advanced flow profiling deep into the reservoir, unconventional and fracture flow, multi annuli leak detection and multi barrier corrosion among others. We pride ourselves not only on equipment technology but also advanced geoscience and interpretation capabilities," he says.   "Saudi Arabia represents one of our most significant markets," he says. TGT has in place a stringent Saudisation development plan and technical knowledge transfer through academia alliances. Referring to Saudi Aramco’s In-Kingdom Total Value Add (IKTVA) plan, he says the published target is 35 per cent by 2020. To celebrate, TGT invited employees, customers, and business partners to an evening which relived the company’s scientific breakthroughs using acoustic, thermal and electromagnetic energy to reveal unique answers within and beyond the well bore.   Dr. Arthur Aslanyan, TGT’s Co-Founder commented, “It gave me great pride to attend the event and celebrate the company's 20th anniversary. We have come a long way since we first started the business. We are very excited about our future as the company continues to thrive”.   The event was attended by Saad Bargach, TGT Chairman and LimeRock Partners -private equity investors.   Hegazi continued, “Looking to our future, TGT is releasing several lines of new technologies and applications in coming months to further cement our position as pioneers of Through-Barrier Diagnostics. Our patent technology developments coupled with our unrivalled Geoscience organisation and global footprint, provide unique and reliable diagnostic services to our customers. This has been key in maintaining our fast growth trend and industry reputation. I am confident this foundation along with our excellent teams, will continue to fuel our growth for many years to come. "TGT will comply with or exceed these targets on all fronts (equipment, human capital, safety and environment) as we establish ourselves further in the kingdom," he asserts. On the company’s relationship with Saudi Aramco, he says Aramco is a highly sophisticated organisation, with a strong emphasis on strategic planning to optmise operations.   "Our relationship, like with all our customers, is built on a foundation technical competence, respect for the accuracy of the results we provide and our service delivery. We ensure we understand the customer’s challenges before designing a bespoke programme to determine the answers they seek," he says.   Referring to business growth, Yassin says business has gradually improved in the last two years in terms of activity.   Pricing of services remains a challenge. The significant rebound of oil price will soon cascade to the market to ensure continued technology development and growth.   "TGT Saudi Arabia is one of our key dedicated business units, supported by a solid global infrastructure. While we continue to expand our global footprint, we will ensure we stay focused on our customers, proving the quality of our diagnostic results, striving to set ourselves apart from our competition," he says.

Diagnostics Behind the Barriers A wide range of tubulars are tested in the EmPulse characterization facility at TGT Oilfield Services’ technology center in Kazan, Russia, to ensure accurate metal wall thickness measurements. Wall thickness is an indicator of barrier condition.   A wide range of tubulars are tested in the EmPulse characterization facility at TGT Oilfield Services’ technology center in Kazan, Russia, to ensure accurate metal wall thickness measurements. Wall thickness is an indicator of barrier condition.   Alongside those efforts, companies are increasingly recognizing the value of using diagnostic systems to detect issues that compromise well barriers. “Because most well integrity problems occur in the outer periphery of the well, behind barriers such as tubulars and cement, a process for sensing and locating leaks, or flow paths along the annulus, is crucial,” said Ken Feather, Chief Marketing Officer, TGT Oilfield Services. The company provides “through-barrier” diagnostics using thermal, electromagnetic (EM) and acoustic energy.   The EmPulse multi-tube imaging system produces tube integrity diagnostics. Measurements performed from within the 3 1/2-in. production tubing show significant corrosion in the 13 3/8-in. casing, quantifying metal loss of 34% and 44% in the third barrier.   The EmPulse multi-tube imaging system produces tube integrity diagnostics. Measurements performed from within the 3 1/2-in. production tubing show significant corrosion in the 13 3/8-in. casing, quantifying metal loss of 34% and 44% in the third barrier.   “Barriers, such as tubulars, cement, elastomers, packers and valves must be in good condition and must have good sealing performance,” he noted. “A barrier may look to be in good condition but not sealing. The mechanical properties of cement, for example, may be robust and provide coverage around the annulus, but it may not be sealing properly because of invisible micro-annuli or cracks that cause unwanted flow paths.” Additionally, cement, tubulars and other zonal isolation components experience degradation over time.   EmPulse multi-tube imaging, in its fourth generation, combines electromagnetic sensors with proprietary measurement and modeling techniques to measure the wall thickness of metal tubulars in well systems. “Wall thickness is an indicator of barrier condition and is used to quantify corrosion, which is progressive over time. Severe corrosion can lead to seal failures, leaks and unwanted flow paths, so routine surveillance is important,” Mr Feather said. In the Middle East, known for highly corrosive aquifers, the system has quantitatively recorded the individual tubular thickness of up to four concentric barriers.   The acoustic-based spectral cement channel detection system records and analyzes the sound spectrum in the wellbore to detect the presence of fluid flow in otherwise undetectable micro-cracks or channels within annular cement that can result in leaks along the annulus after the well is put on production.   “From a production standpoint, this capability is important, particularly where one reservoir is communicating with another in a producing well,” he noted. “In water injection wells, the technique can confirm if the injected water is reaching the target reservoir or being diverted elsewhere.” Integrity failures resulting in sustained annulus pressure are often visible at the surface before problems escalate, so operators are embracing diagnostics as a proactive method for preventing zonal isolation issues, particularly in the Middle East, he said. “Historically, the industry has been reactive, but we believe there are significant benefits in conducting surveillance regularly and routinely to monitor the tube integrity and seal integrity of wells barriers.” Pulse characterisation lab