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Exert from Harts E&P's showcase on the latest hydraulic fracturing technologies and how they aim to address operator challenges. Diagnostics locate flow before or after fracturing TGT’s Fracture Flow evaluates the effectiveness of a fracturing program. It uses the Chorus acoustic platform to record and analyze the acoustic wave propagation in the wellbore and rocks, plus well design information, to determine the location of the acoustic source energy produced by fluid flow in the fractures. When used during pre- and post-fracturing, it can analyze the reservoir flow profiles, qualify flow to or from the fracture network, reveal fracture density and identify unwanted fracture components that impact product. The technique can identify the location and determine the distance of the acoustic signal from the receiver. Combined, these insights offer operators the diagnostics they need to improve their fracturing program, so it can be targeted and optimized to deliver maximum time and cost efficiencies. The logplot shows a horizontal tight sand gas condensate producer, completed with a non-cemented multistage ball-activated application. Stage separation was achieved by a dual hydraulic-activated packer. The results identified the presence of 22 active fractures, 17 were offset from flow ports and five could be aligned with the flow ports producing a unique signature covering a wide frequency range. The fracture distribution varied between stages with an average of three active fractures per stage.
Challenge Multistage fracturing is an effective stimulation technique for heterogeneous, low-permeability oil reservoirs. However, after a fracturing campaign, there may be a risk of increased communication between the water-bearing formation, which may cause a high water cut in the stimulated well. In this case from the Volga-Ural region of Russia, the operator wanted to identify unexpected water sources in a horizontal well in a low-permeability carbonate reservoir. The well had been subjected to a multistage acid fracturing job and it was necessary to determine the most effective strategy for a workover to shut off the water producing zones. Well sketch shows flow scenarios before and after fracturing that Fracture Flow can evaluate. Fracture Flow provides the clarity and insight needed to manage well system performance more effectively. Solution The operator selected TGT’s Fracture Flow product to understand the flow dynamics of the well system and identify the water sources. Fracture Flow is delivered by the True Flow diagnostic system. TGT’s diagnostic systems combine several proprietary technology platforms that share a common structure and workflow comprising programs and methods; tools and measurements; processing and modeling; and analysis and interpretation. The Chorus (acoustic) platform records and analyses the acoustic energy produced by fluid flow; its role in this case was to help pinpoint unexpected flow activity behind casing. The Fracture Flow product uses a multi-sensor tool, adopts a unique data acquisition programme and utilises a processing and modelling software plugin which varies from the other True Flow products. In combination, the technique is able to identify the location and determine the distance of the acoustic signal from the receiver. It is therefore able to distinguish reservoir flows from those generated by completion leaks. Integrated logging suite results: Acoustic signal source identification Result An acoustic signal was recorded in a narrow interval above the target reservoir. This signal had a broadband spectrum that could have been generated by reservoir flow or by a completion leak (see Line A in Figure 1). Taking into consideration the well design and the acoustic wave propagation in the wellbore and rocks, TGT’s Chorus diagnostics determined that the location of the acoustic source extended beyond the wellbore. It was deduced that the signal was generated by turbulent flow from an unexpected fracture above the target reservoir. The inflow fluid from this unwanted fracture flowed back down the well completion, entering the wellbore through the topmost perforation. It was this rogue fracture that was the cause of water in the well production. Thanks to Fracture Flow’s diagnostic results, the operator changed the hydraulic fracturing design programme, to optimise production while preventing the reoccurrence of rogue fractures in the future.
Kazan, Russia, 2018: TGT Oilfield Services, the market leader in through-barrier diagnostic systems, celebrated 20-years of Research and Development and technological advancements. Mohamed Hegazi, Chief Executive Officer, said: “We are delighted to have reached this milestone, especially in an increasingly competitive market place and at a challenging time in our industry. We enjoyed our celebration with valued employees, partners, and customers from around the world. This achievement is a testament to the uniqueness and strength of TGT ‘s technologies, Geoscience expertise and best in class service delivery”. “The past 20-years have been an incredibly exciting time for us. We have continuously outpaced the market growth, expanded our geographical footprint and continue to be actively engaged in industry forums and publications. TGT uniquely designs, develops, manufactures and patents its own hardware and software”. TGT has grown from a small office with a handful of employees, to a company with 12 offices globally, operating in more than 20 countries for more than 40 customers. Mohamed Hegazi, CEO, TGTBringing global colleagues together to celebrateArthur Aslanyan, Founder, TGTTraditional Russian dance 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.
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.
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
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.
Challenge A dual-string completion is a cost-effective method for producing from multilayered reservoirs using a single wellbore. However, the perforation interval in the upper reservoir is not usually surveyed because of safety concerns about conventional tools becoming entangled around the long string as they exit below the short-string tubing shoe. An Abu Dhabi offshore well was drilled and completed as a dual-string producer in 2014. However, the well showed a 20%-water cut, presumably from the aquifer. The principal challenge was to evaluate the production profile in the short string and find the true source of water. This would require a diagnostic platform with a depth of investigation that extended beyond the tubing. Well sketch shows a range of typical flow scenarios that Dual String Flow can locate and quantify. Solution The operator selected TGT’s Dual String Flow product for evaluating the short-string production profile in the well. Delivered by the True Flow diagnostic system, using the Chorus acoustic platform and Cascade thermal platform, Dual String Flow could provide the insights needed to manage well system performance more effectively. Cascade high-precision temperature and Chorus spectral acoustic surveys were carried out under flowing and static conditions. Both platforms have large radii of investigation and can detect acoustic signals and temperature variations caused by fluid flowing in the reservoir into the wellbore. Chorus can record acoustic signals through multiple pipe barriers and up to 3 m into the reservoir. The active production zones and thicknesses identified using Chorus were used as input for Cascade’s temperature modelling and to produce quantitative reservoir production profiles. The temperature modelling also required production history data, the thermophysical properties of the reservoir and the surrounding rocks, the geothermal profile, the hydrodynamic reservoir parameters and the well trajectory including completion components. Behind-casing crossflow from upper unperforated units Result The Chorus survey and analysis (Chorus panel in Logplot) clearly show two acoustic signals which relate to the reservoir flow: the first across the upper part of perforated unit C (zone 1) and the second from the unperforated units A and B (zone 2). Cascade modelling showed that 35% of the total production was coming from the unperforated units A and B, with the fluid crossflowing behind tubing and casing, entering the wellbore through the perforation in the tubing. There was no production from the lower part of unit C or in unit D. Cascade temperature modelling indicated that the fluid inflow from the upper part of unit C was redistributed behind the casing and enters the wellbore across the perforated interval, although only the upper interval is actually contributing to production. Behind-casing communication with off-target formations and the actual distribution of production for the target reservoir zones were identified and quantified. Despite not being able to distinguish between oil and water, the diagnostics could make the correlation with open hole data, thus making it possible to determine that 20% of water was coming from the off-target unit B. The operator was able to use information acquired by the Dual String Flow product to improve the vertical sweep around the surveyed well by selecting the most appropriate workover for the well—water shut-off and acid stimulation.