Two-phase and single-phase pressure drop data were obtained for flow in horizontal 5.08-cm-dia pipe and piping components that included: a 9.14-m straight section of pipe; a gate valve; an elbow; a combination of elbow and gate valve separated by different pipe lengths; a globe valve; a swing check valve; and a union. Single-phase pressure drops produced by each component were used to establish the resistance coefficient, K. This resistance was then used to calculate two-phase pressure drops for each component using the Tremblay and Andrews homogeneous flow model. An acceptable agreement was found between measured and predicted pressure drops for all piping components studied. Pressure recovery lengths for individual components were found to be 10–50 pipe diameters, depending on flow rates. The resistance coefficient of two components separated by a distance less than the recovery length was always greater than the summation of each individual resistance coefficient.
The application of high-resolution fiber optic distributed acoustic sensing (DAS) and distributed temperature sensing (DTS) during multistage hydraulic fracturing has increased in recent years. However, fiber optic has been used for communication networks, surveillance, and monitoring and diagnosing wellbore integrity for quite some time. The technology has also been used to diagnose reservoir and well performance, e.g., production and injection profiling. Optical fibers were placed in a small stainless steel tube, which was clamped to the casing while running in the hole in a horizontal unconventional gas well. The casing was then cemented in place, and fracturing treatments were completed by limited-entry techniques using the "plug & perf" process, resulting in multicluster (each stage), multistage fractures. Perforations were placed on the topside of the casing, oriented to avoid damaging the optical fiber (zero degree phasing, at 5 shots per foot, one foot per cluster). This paper shares images and results from DAS and DTS data that allow for interpretation of fracturing treatments in multicluster, multistage horizontal wells. The images illustrate the dynamic nature of the spatial and temporal fluid distribution pertaining to initiation, propagation and arrest of hydraulic fractures during simultaneous stimulation of multiple clusters. First, fracture initiation appears not only during early time, as expected, but also late time initiation events may develop in previously dormant clusters. Second, propagation of multiple fractures can occur randomly within a cluster array, and these multiple fractures are sometimes in close proximity to one another. Third, dominant clusters are often observed during stimulation. Further, during the treatment cycle, the position of dominant cluster(s), within a given stage, may actually change. We leverage these observations with various other data sources in a modeling exercise to demonstrate the implications of unequal fracturing fluid distributions on propped fracture performance.
Waterflooding is an established conventional method to improve oil recovery. When water flows into pores in a rock formation occupied by hydrocarbons, clays and other formation fines are released and flow with the injection water. Left unaddressed, the released formation particles can accumulate and plug the pore throats in the flow channels, which cause higher water injection pressure, lower water sweepefficiency and lower oil recovery. Chemical additives in the injection water to stabilize formation clays and fine particles during waterflooding operations are partially helpful. Several major operators established a goal for 70% oil recovery, motivating the research of higher performing waterflooding formulations. As the nanoparticle-loaded water drives hydrocarbons toward the producers, the nanoparticles fixate formation fines at their sources in the water flow channels, resulting in fewer fines accumulating at the near-wellbore region of the producers (causing less choking to the production of hydrocarbons) and resulting in water-sweep-efficiency increases. This paper presents the results with and without using nanoparticles in simulated waterfloodings. In addition to cleaner water effluent, lower pressure drop occurs across the porous media containing nanoparticles under the same flow rate of 5%KCl and the same porous media compositions of sand and simulated formation fines. Full reservoir simulation details the benefits of coupling the nanoparticles and waterflooding in high fines-containing reservoirs with various reservoir properties. This paper presents the use of select nanoparticles in waterflooding to significantly improve oil recovery in reservoirs susceptible to formation fines migration. The research shows the unique ability of select nanoparticles in stabilizing formation clays and fines in waterflooding operations. The lab results demonstrate a much higher performance of the new nanoparticle-blended waterflooding than the currently used technology of stabilizers for formation clays and fine particles. Lab tests, even visually, show a clear improvement of the water-effluent quality (less fines) when the nanoparticle-blended waterflooding is pushed through the lab-constructed permeable media. The simulation resulted in 37% more production than regular waterflooding in a higher permeability reservoir case and 95% greater production in a lower permeability reservoir scenario. The paper includes the scientific principle behind the nanoparticle functioning, detailed lab results and the reservoir simulations.
Fiber optic distributed temperature sensing (DTS) and distributed acoustic sensing (DAS) have been used to monitor and diagnose the integrity of wellbores (leak detection, gravel-pack screen damage, formation subsidence, etc.), the performance of reservoirs and wells (production profile, injection profile, etc.), used for surveillance and other applications for quite some time. The application of high resolution fiber optic DAS and DTS during multi-stage hydraulic fracturing has increased in recent years.In this horizontal tight-gas well, the fiber optic filaments were placed in a small stainless steel tube which was clamped to the casing while running in hole, and the casing was then cemented in place. Perforations had to be oriented to avoid damage to the fiber optic. In this case, perforations were place at the topside of the casing, zero degree phasing, at 5 shots per foot (1 foot per cluster). This paper shares results from DAS and DTS techniques that allow for interpretation of fracturing treatments in multi-cluster (each stage), multi-stage horizontal well with cemented casing and 'plug and perf' completion process. The images illustrate the dynamics pertaining to initiation, propagation and arrest of hydraulic fractures during simultaneous stimulation of multiple clusters. First, fracture initiation appears not only during early time, as expected, but late time initiation events may develop in seemingly dormant clusters. Second, propagation of multiple fractures can occur randomly within a cluster array. Third, dominate clusters are often observed during stimulation. Further, during the treatment cycle, the position of dominate cluster(s), within a given stage, may actually change.
Fiber optic distributed temperature sensing (DTS) and distributed acoustic sensing (DAS) have been used to monitor and diagnose the integrity of wellbores (leak detection, gravel-pack screen damage, formation subsidence), the performance of reservoirs and wells (production profile, injection profile), used for surveillance and communication networks for quite some time. Though still somewhat novel, the application of high-resolution fiber optic DAS and DTS during multistage hydraulic fracturing has increased in recent years. This paper shares DAS and DTS images of fracture initiation, fracture propagation and fracture progression during fracturing treatments of multicluster (each stage), multistage horizontal tight-gas well. The images illustrate the dynamics pertaining to initiation, propagation and arrest of hydraulic fractures during simultaneous stimulation of multiple clusters. First, fracture initiation appears not only during early time, as expected, but late time initiation events may develop in seemingly dormant clusters. Second, propagation of multiple fractures can occur randomly within a cluster array. Third, dominate clusters are often observed during stimulation. Further, during the treatment cycle, the position of dominate cluster(s), within a given stage, may actually change.
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