Single-Phase Retarded Inorganic Acid Optimizes Remediation of Drilling Formation Damage in High-Temperature Openhole Horizontal Carbonate Producer

2021 ◽  
Author(s):  
Ahmed Mohamed Fawzy ◽  
Noor Nazri Talib ◽  
Ruslan Makhiyanov ◽  
Arslan Naseem ◽  
Nestor Molero ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Middle East ◽  
Fiber Optics ◽  
Single Phase ◽  
Mixing Time ◽  
Well Testing ◽  
Inorganic Acid ◽  
Distributed Temperature Sensing ◽  
Horizontal Section

Abstract In high-temperature carbonate producers, conventional hydrochloric (HCl) acid systems have been ineffective at delivering sustainable production improvement due to their kinetics. Retarded acids are deemed necessary to control the reaction and create effective wormholes. This scenario is even more critical in wells completed across long openhole horizontal intervals due to reservoir heterogeneity, changing downhole dynamics, and uniform acid placement goals. Out of the different retarded acid options, emulsified acid is one of the preferred choices by Middle East operators because of its excellent corrosion inhibition and deep wormhole penetration properties. However, it also brings other operational complexities, such as higher friction pressures, reduced pump rates, and more elaborate mixing procedures, which in some cases restrict its applicability. The recent introduction of a single-phase retarded inorganic acid system (SPRIAS) has enabled stimulation with the same benefits as emulsified acids while eliminating its drawbacks, allowing friction pressures like that of straight HCl and wormholing performance equivalent to that of emulsified acid. A newly drilled oil producer in one of the largest carbonate fields in onshore Middle East was selected by the operator for pilot implementation of the SPRIAS as an alternative to emulsified acid. The candidate well featured significant damage associated with drilling, severely affecting its productivity. The well was completed across 3,067 ft of 6-in. openhole horizontal section, with a bottomhole temperature of 285°F, permeability range of 0.5 to 1.0 md, and an average porosity of 15%. Coiled tubing (CT) equipped with fiber optics was selected as the fluid conveyance method due to its capacity to enable visualization of the original fluid coverage through distributed temperature sensing (DTS), thus allowing informed adjustment of the stimulation schedule as well as identification of chemical diversion and complementary fluid placement requirements. Likewise, lower CT friction pressures from SPRIAS enabled the utilization of high-pressure jetting nozzle for enhanced acid placement, which was nearly impossible with emulsified acid. Following the acidizing treatment, post-stimulation DTS showed a more uniform intake profile across the uncased section; during well testing operations, the oil production doubled, exceeding the initial expectations. The SPRIAS allowed a 40% reduction in CT friction pressures compared to emulsified acid, 20% optimization in stimulation fluids volume, and reduced mixing time by 18 hours. The experience gained with this pilot well confirmed the SPRIAS as a reliable option to replace emulsified acids in the region. In addition to production enhancement, this novel fluid simplified logistics by eliminating diesel transportation, thus reducing equipment and environmental footprints. It also reduces friction, thus enabling high-pressure jetting via CT, leading to more efficient stimulation with lower volumes.

New Perspectives for Acidizing Tight Carbonate Oil Producers Completed Across an Extended Openhole Horizontal Section

2021 ◽  
Author(s):  
Maad Hasan Qayad Subaihi ◽  
Muhammad Syafruddin ◽  
Avnish Kumar Mathur ◽  
Jaber Abdulmajeed Abdulla ◽  
Nestor Molero ◽  
...  
Keyword(s):  
High Pressure ◽  
Middle East ◽  
Real Time ◽  
Fiber Optics ◽  
High Energy ◽  
Optimal Operation ◽  
Distributed Temperature Sensing ◽  
Horizontal Section ◽  
Tight Carbonate ◽  
Open Hole

Abstract Over the past decade, coiled tubing (CT) has been one of the preferred fluid conveyance techniques in tight carbonate oil producers completed with an uncased horizontal section. In the onshore Middle East, conventional CT stimulation practices have delivered inconsistent results in that work environment. This is mainly due to a mix of reservoir heterogeneity, limited CT reach, lower CT pumping rates, uncontrolled fluid placement, and uncertainty of downhole dynamics during the stimulation operations. An intervention workflow recently validated in onshore Middle East to acidize tight carbonate openhole horizontal water injectors was introduced for the first time in an oil producer. The advanced stimulation methodology relies on CT equipped with fiber optics to visualize original fluid coverage across the openhole interval through distributed temperature sensing (DTS). Real-time downhole telemetry is used to control actuation of CT toolstring components and to understand changing downhole conditions. Based on the prestimulation DTS survey, the open hole is segmented into sections requiring different levels of stimulation, fluid placement techniques, and diversion requirements. The candidate carbonate oil producer featured an average permeability of 1.5 md along 8,003 ft of 6-in. uncased horizontal section. Because of the horizontal drain's extended length and the presence of a minimum restriction of 2.365-in in the 3 1/2-in. production tubing, a newly developed CT slim tractor was essential to overcome reach limitations. In addition, a customized drop-ball high-pressure jetting nozzle was coupled to the extended reach assembly to enable high-energy, pinpoint acidizing in the same run. The instrumented CT was initially run until lockup depth, covering only 53% of the horizontal section. The CT slim tractor was then precisely controlled by leveraging real-time downhole force readings, enabling full reach across the open hole. Prestimulation DTS allowed identification of high- and low-intake zones, which enabled informed adjustments of the acidizing schedule, and in particular the level of jetting required in each section. After its actuation via drop-ball, the high-pressure jetting nozzle was operated using downhole pressure readings to ensure optimum jetting conditions and avoid exceeding the fracturing threshold. Upon completion of the stimulation stage, post-stimulation DTS provided an evaluation of the fluid placement effectiveness. After several weeks of production, the oil rate still exceeded the operator's expectations fivefold. This intervention validates the applicability of the advanced matrix stimulation workflow in tight carbonate oil producers completed across a long openhole horizontal interval. It also confirms the value of real-time downhole telemetry for optimal operation of extended reach toolstrings and the understanding of the downhole dynamics throughout stimulation treatments, the combination of which ultimately delivers breakthrough production improvements compared to conventional stimulation approaches, in a sustainable manner.

scholarly journals Mechanical and Electrical Characteristics of WB2 Synthesized at High Pressure and High Temperature

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1212 ◽  
Author(s):  
Changchun Wang ◽  
Lele Song ◽  
Yupeng Xie
Keyword(s):  
Grain Size ◽  
High Pressure ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Vickers Hardness ◽  
Single Phase ◽  
Hard Material ◽  
Experimental Conditions ◽  
Boundary Density ◽  
Grain Sizes

Single-phase tungsten diboride (WB2) was synthesized at high pressure and high temperature. The different grain sizes ranging from 300 nm to 3 µm were successfully obtained in WB2 by controlling the experimental conditions. The effects of grain size on hardness and resistivity properties were investigated. The Vickers hardness of WB2 was modulated with grain size. The maximum asymptotic Vickers hardness is 25.5 GPa for WB2 with a grain size of 300 nm which is a 10% increase compared to WB2 with a grain size of 3 µm. The optimal electrical resistivity of WB2 was 10−7 Ωm with the biggest grain size of 3 µm, which is ascribed to low grain boundary density. The superior properties of hardness and electrical resistivity demonstrate that WB2 should be a new functional hard material replacing WC which is widely used in industrial production.

Feasibility Analysis of Reverse Sealed Testing String in HPHT Wells

2014 ◽  
Vol 556-562 ◽  
pp. 2761-2764
Author(s):  
Bao Kui Gao ◽  
Wei Wang ◽  
Xing Qin
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Axial Force ◽  
New Technology ◽  
Feasibility Analysis ◽  
Well Testing ◽  
Axial Deformation ◽  
High Pressure High Temperature ◽  
Key Factor ◽  
Testing Design

To solve problems met in an offshore High-Pressure High-Temperature (HPHT) well testing, a new technology is put forward—placing seal bore extension above permanent packer, and the upper landing tools being connected with seal bore extension through shear pins. This method gives a reverse position of seal bore extension compared with conventional way in which seal bore extension is below permanent packer. So, the feasibility must be considered. Two technological procedures, testing before cutting pins and testing after cutting pins, are discussed, and the highlight is on axial force and deformation of testing string at crucial moments. Results indicate that this new technology is feasible. Of the two technological procedures, axial force is the key factor when testing before cutting pins and axial deformation is the key factor when testing after cutting pins. Conclusions have been used in an offshore HPHT well testing design.

scholarly journals Fiber-Optics Video Probes for Observation of High-Pressure High-Temperature Two-Phase Flow.

1992 ◽  
Vol 12 (47) ◽  
pp. 257-266
Author(s):  
Hideo NAKAMURA ◽  
Hideo MURATA ◽  
Hideo ITOH ◽  
Yoshinari ANODA ◽  
Hiroshige KUMAMARU ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Fiber Optics ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
High Pressure High Temperature

The First Behind-Casing Fiber-Optic Installation in a High-Pressure High-Temperature Deep Gas Well in Oman

2022 ◽  
Author(s):  
Sultan Salim Al Shoaibi ◽  
Juan Chavez Florez ◽  
Shaima Al Farsi ◽  
Adnan Al Hinai ◽  
Alvaro Nunez ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Fiber Optic ◽  
Production Performance ◽  
Distributed Temperature Sensing ◽  
Gas Wells ◽  
Fiber Optic Cable ◽  
Gas Well ◽  
High Pressure High Temperature ◽  
The Impact

Abstract This paper discusses the first fiber-optic (FO) installation in a vertical high-pressure high-temperature deep gas well in PDO, Oman. A specially designed fiber-optic cable was successfully installed and cemented behind the production casing, which was subsequently perforated in an oriented manner without damaging the cable. This paper also describes how the fiber-optic cable was used afterwards to acquire Distributed Acoustic Sensing (DAS) and Distributed Temperature Sensing (DTS) data for the purpose of hydraulic fracturing diagnostics. Fiber-optic surveillance is becoming an increasingly important activity for well and reservoir surveillance. The added complexity of the fiber-optic installation will affect the well design, which is one of the elements that requires focused attention, especially when the fiber is installed behind casing. The impact on casing design, wellhead design, perforation strategy, and logging requirements will all be discussed. In order for a well to be completed with a permanent fiber-optic cable, a few critical procedures need to be followed, including: –modifying the wellhead design to include feedthrough ports for the cable;–optimizing the cement design;–imposing strict procedures to ensure the cable is installed behind the casing without getting stuck;–changing the perforation phasing to avoid damaging the cable;–mapping the location of the cable to allow the gun string to be oriented away from the cable. The fiber-optic cable itself needed to be designed to be protected in such a way that it would not be damaged during installation and completion (perf/frac) activities. Furthermore, the cable was also optimized to improve its detectability, to aid the oriented perforation. In deep gas wells, much more than in conventional shallow water injectors or oil producers, the well integrity aspect should be given special attention. Specifically, any risks related to unwanted gas leaks, either through the control line, poor cement, or because of other design errors should be avoided. In deep gas wells, high temperature and pressure will also play a big role in the expected lifespan of the cable. Finally, the well was hydraulically fractured in four stages, using the "plug-and-perf" technique, during which DAS and DTS data were acquired continuously and across all depths of the well. The data provided valuable information on the effectiveness of each of the frac stages, it could be used to analyze screen-outs and detect out-of-zone injection, and recommendations for the optimizations of future hydraulic frac designs could be derived. The fiber-optic data were also integrated with other open-hole data for improved understanding of the reservoir performance. The next step will be to acquire repeated time-lapse DAS and DTS data for production profiling, to gain more insights of how the long-term production performance is affected by the hydraulic frac operations.

Microstructural Study of Diamond Deformed Under High Pressure and Temperature

1985 ◽  
Vol 43 ◽  
pp. 230-231
Author(s):  
E. F. Koch
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Lattice Structure ◽  
Diamond Particle ◽  
Polycrystalline Diamond ◽  
Sintering Process ◽  
Ion Milling ◽  
Sintered Compact ◽  
Transmission Electron ◽  
High Pressure Sintering

Because of the extremely rigid lattice structure of diamond, generating new dislocations or moving existing dislocations in diamond by applying mechanical stress at ambient temperature is very difficult. Analysis of portions of diamonds deformed under bending stress at elevated temperature has shown that diamond deforms plastically under suitable conditions and that its primary slip systems are on the ﹛111﹜ planes. Plastic deformation in diamond is more commonly observed during the high temperature - high pressure sintering process used to make diamond compacts. The pressure and temperature conditions in the sintering presses are sufficiently high that many diamond grains in the sintered compact show deformed microtructures.In this report commercially available polycrystalline diamond discs for rock cutting applications were analyzed to study the deformation substructures in the diamond grains using transmission electron microscopy. An individual diamond particle can be plastically deformed in a high pressure apparatus at high temperature, but it is nearly impossible to prepare such a particle for TEM observation, since any medium in which the diamond is mounted wears away faster than the diamond during ion milling and the diamond is lost.

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