The global demand for energy has led to an industry focused on increasing process efficiency with respect to innovative techniques for hydraulic fracturing stimulation. One such innovative process is coiled tubing (CT) deployed pinpoint stimulation. Pinpoint multistage fracturing with hydrajetting perforation technique is a solution that enables fracture placement in virtually an unlimited number of fracturing stages in long lateral sections, with a single trip into the wellbore. The evolution of pinpoint stimulation technology and its benefits have been recognized in many papers published along the years.In some variations of the pinpoint stimulation technique, the bottomhole assembly (BHA) is activated by ball drop and reverse circulation of the ball. This process has been improved with a new generation design of the BHA, which renders the operation capable of being entirely controlled remotely from the surface using movement of the CT string. The ball drop activation is eliminated. This allows real-time, on-demand control of the tool setting. Based on traditional proven pinpoint solutions and adopting this new way of well stimulation, the pinpoint multistage fracturing method has become more efficient. This improved BHA, in conjunction with a proprietary pinpoint stimulation process, can help reduce water consumption on location and horsepower requirements, reduce idle time between fracturing treatments, reduce pump time per stage, and help prevent ball drop difficulties, all without having to make changes to the fracturing spread, equipment, and CT on location.The improved BHA enables hydrajet perforation, hydraulic fracturing using real-time downhole proppant concentration control, and proppant plugs to be set for zonal isolation. Additionally, multicycle sequences can be repeated in long lateral and vertical wells. It also helps assist centralization of the BHA during perforating operations to help maintain appropriate jet standoff distance. This paper presents the development approach of the aforementioned improved BHA, and a means to manipulate it from the surface. Validation during field testing is also outlined.

Computational fluid dynamics (CFD) has been actively used to make flow profile predictions in down hole oil and gas environments. The flow in oil wells inherently consists of oil, water, and gas phases. Flow profile predictions are complicated by parameters such as fluid properties, flow velocities, area, and well inclination. A proper understanding of flow behavior under various operating conditions is critical when designing down hole equipment and flowmetering applications. This paper presents case studies involving the three-phase flow of oil-water-gas in a down hole tubular. Phase distribution is analyzed for different compositions by varying the individual phase volume fractions. Various flow regimes, such as stratified flow, homogeneous flow, and bubbly flow, are studied individually as well as in their transition from one regime to another. The transition criteria were also studied. Extensive efforts were focused on understanding random bubble distribution, bubble breakup, bubble-relative movement, distortion, and diffusion in fluid flow with respect to flow variables. Finite volume phase distribution for oil vs. water is obtained as a function of time and distance (coherence) for multiphase flow in production tubulars. The effect of geometry changes with the objective of flow homogenization is also studied to enable the locations and numbers of monitoring devices to be fixed. CFD results were found to be comparable to single-phase analytical solutions. The examples and references included in the paper demonstrate the accuracy of the study results. The studies verify that an understanding of flow dynamics is essential to evaluate optimum configurations of the variables described. Advanced knowledge of flow characteristics enables engineers to deliver robust and maintenance-free sensing technology for use in a subterranean environment.

Fluid movement devices use upstream energy to move fluid from one location to another. Flow nozzles that slightly accelerate fluid motion, especially into the same direction, often exhibit discharge coefficients greater than 1.0. Jet nozzles, however, by definition, create a jet stream that is much faster than the upstream fluid, often exceeding 100-fold higher velocities. Energy used to move this fluid is often very high; jetting efficiencies are generally less than 1.0 and will only approach 1.0 if the shape of the entrance is such that there is no “vena contracta” within its flow regime inside the nozzle. High-pressure nozzles require high horsepower to generate high-velocity fluids. As is commonly performed, power is created using high-powered pumping equipment. Oftentimes, nozzles are used to jet in locations that have high ambient pressures, such as at the bottom of the ocean or inside a deep oil well. At these locations, the hydrostatic pressures could be very high. Pressure at the upstream side of the nozzle would be even higher. This paper discusses the design and use of a unique nozzle that uses the hydrostatic (potential) energy to accelerate the fluid velocity of the jet. In essence, the nozzle uses the downstream energy to perform part of its job, thus, substantially reducing the upstream pressure requirement. This phenomenon was proven to occur using CFD analysis. Laboratory tests have shown apparent discharge coefficients between 1.38 and 1.69, depending on the downstream pressure.