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Technology Applications

Logging-While-Drilling Sonic Tool

Understanding the geomechanical properties of shale, which control the occurrence of natural fractures and the creation of hydraulically induced fractures, is key to successful stimulation and completion of wells in a shale reservoir. Weatherford developed the CrossWave logging-while-drilling (LWD) sonic tool that provides 360° azimuthally focused measurements of compressional- and shear-wave velocities (Fig. 1), enabling 3D characterization of geomechanical properties (e.g., Poisson’s ratio and Young’s modulus) along the whole length of the horizontal wellbore in mechanically anisotropic shale reservoirs. Thereby, the operator can select the best areas for fracturing-stage placement while optimizing the fracture-treatment design and execution. The LWD azimuthal sonic technology has been tested successfully in horizontal shale-reservoir wells in the northeastern US, where vertical-­transverse-isotropy shear-wave anisotropy of 5–50% was clearly measured in the horizontal sections. Borehole images constructed from azimuthal shear-slowness data provided a clear visual indication of the orientation and magnitude of the shear-wave anisotropy. Compressional-slowness borehole images compared with conventional images from LWD azimuthal gamma ray and density tools can provide information on formation dip and the stratigraphic position of the horizontal wellbore.

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Optimize Completion Efficiency

Halliburton has introduced its Knoesis service. This service provides software applications for use by the company’s stimulation technical advisors to assist operators in optimizing completion efficiency and asset development. The applications provide improved knowledge of the reservoir and its stimulation characteristics. Two components of the software are available. Shale formations need fracture complexity to produce well. In many cases, the complexity of the reservoir is not well understood. Foray provides insight into the fracture network created by generating a 3D representation from microseismic events observed during the treatment. The representation allows design decisions to be made to control the nature of the fracture network generated in the reservoir. The application generates images automatically by use of advanced unbiased mathematics. Delve enables analysts to access historical and current-job-design data along with operating experience that can be leveraged to the operators’ advantage through enabling improved stimulation-job design and execution. This proprietary technology is highly secure and carefully engineered to provide the technical representative direct access to Halliburton’s global job archive, which contains terabytes of historical and up-to-date data. The service enables technical advisors to reveal how the reservoir responds to stimulation treatments and the level of complexity that the treatment creates.

Flood-Injection Models

To return produced water to reservoirs, it must be suitably clean. Therefore, it must be tested and found fit for purpose. A water sample must be drawn and sent to an onshore laboratory for testing. Formation modeling would be based on the results. Unless the water is tested in situ, the values can change dramatically during transport and while waiting to be analyzed. Global Industrial Water designed and built a mobile, high-pressure-test system capable of mimicking the injection site exactly. The Portable Apparatus for Coreflood Evaluation—PACE—system (Fig. 2) is capable of finding the equilibrium between injector plugging and the magnitude of the fracture, defining changing leakoff aspects, and delivering accurate data. The system enables operators to feed test results directly to an on-site/onboard data-collection program producing immediate, accurate, and real-time results for the specific site. The system has been field tested on a rig in the Gulf of Mexico. This testing enabled real-time analyses of flood water with cores from that specific well. The data points were collected and the particle sizes determined by the onboard camera, after which the software analyzed the different filtration anomalies. Filter-cake data then were documented, informing the operator about the effects of that specific injection water on the matrix permeability.

Radial Probe Samples the Tight Ones

The Schlumberger Saturn 3D radial probe technology extends fluid sampling to previously inaccessible fluids and reservoir environments with a 1,200% increase in flow area over the largest conventional single-probe formation tester. This makes it ideal for tight formations, heavy oil, unconsolidated formations, near-critical fluids, and rugose boreholes. As a fully compatible option for the modular formation dynamics tester, the module features four orthogonally phased, self-­sealing, elliptical suction probes in a single expandable-packer element. Surpassing the operating envelope of previous systems, the tester can acquire precise formation-pressure and fluid-mobility measurements to the microdarcy level and sample fluids having mobilities less than 1 md/cp. Recently, in the Middle East, the probe demonstrated the benefits of its 650%-greater flow rate to obtain representative samples within a tight time window imposed by the operator because of local mud losses in the zone (Fig. 3). With the tool’s fast cleanup capability, two low-mobility-oil samples, in the range of 1.5 to 2.2 md/cp, were acquired successfully. In a heavy-oil well in Mexico, the probe demonstrated the benefits of its 79-in.2-surface flow area to obtain uncontaminated samples. With the inflatable packer supporting the unconsolidated formation, and the tool’s fast cleanup capability, a 7.5°API oil sample was acquired from the friable sandstone.

Extended-Length-Tool Deployment

Peak Well Systems has introduced its 90Degree Safe Connect (Fig. 4), a connection tool that facilitates safe deployment of rigid extended-length assemblies into a well with a safe working load of 3 t. The connector’s pivoting design enables oversized items to be raised safely and securely from a horizontal position to a vertical position during the deployment process and vice versa when being removed from a well. During this operation, the wire and tool components can sustain undue stress and bending that can cause damage to the equipment and can lead to potential harm to personnel if the wire or tool component fails. The connector is placed directly above the long assembly while in the horizontal position and provides a hinge or pivot when the assembly is being raised to the vertical position. Once vertical, the internal latch automatically locks the connection to form a rigid tool that can sustain upward and downward jarring during any setting or pulling process. To return the connection to pivot mode, the latch is locked into the release position by use of an integral J-slot mechanism. The patent-pending fail-safe design will not disconnect unless intended.

Real-Time Reservoir Monitor

The Kuster K Perm software’s capabilities range from setting the gauges’ sampling rates to uploading the calibration coefficients. The software can archive the data locally or transmit it to a central monitoring point. It also has the ability to graphically display real-time data, as well as historical data. System components include a wellhead-pressure-­barrier outlet (dry tree), a real-time surface data-acquisition unit, a permanent downhole cable, a gauge mandrel, and a permanent real-time quartz gauge. The permanently installed downhole pressure/temperature gauge with real-time surface readout provides reliable reservoir-monitoring data. The gauge is run into the well on monoconductor cable and is clamped onto the production tubing as an integral part of the completion. Once commissioned, it transmits data to the surface continuously for collection and real-time readout. The system is designed for pressures up to 10,000 psi and temperatures to 392°F. The approximately 30-in.-long gauge has an outside diameter of 1.00 in., and it uses a Quartzdyne digital quartz transducer. Applications include life-of-well production monitoring, pressure-buildup monitoring, injection monitoring, and reservoir optimization. The surface unit can be programmed with adjustable storage rates to meet required needs. The software is user upgradeable for future expansion, and data can be exported to a portable storage device.

Proppant Coating

Webac offers flexible ways to meet specific ceramic- and sand-coating requirements with a range of its Proppants Mixer. The heart of any coating plant is the proppants mixer, to mix and activate the raw materials with the predosed chemicals. This process determines the required quality of the coated proppants. The significant advantage of these mixers is that they transfer the energizing power effectively from the two mixing wheels to the coating of each proppant grain (Fig. 5). The result is superior overall resin distribution and desired thin coating levels. Adjusting the mixer speed and the coating pressure to the specific proppants ensures the best coating results. An important precondition is a homogeneous temperature of the raw material. The Sandheater heats the sand to the required temperature within an exact cycle time and distributes the heat to the sand batch uniformly. Each sand grain passing the gas flame is heated uniformly and retains its heat during the processing cycle because of a specially designed protection plate that enables additional heat transfer to the grain.

Coring While Drilling

The Tercel MicroCORE bit is the result of an extended research and development program led in collaboration with Total. The bit was developed by Diamant. The bit enables a small-diameter core to be cut while drilling. This design delivers comparable performance to that of conventional drill bits, while continuously providing larger high quality core fragments for enhanced real-time   formation evaluation by the Geologist. The small-diameter core of the formation being drilled is generated in the center area of the bit, where the cutting structure is interrupted, and this process occurs continuously as drilling progresses. While drilling, the small-­diameter core advances to its nominal length, reaching a core breaker that applies lateral force on the core that induces rock failure (Fig. 6). The small-diameter core moves into the annulus through an evacuation area, which is a larger and deeper slot between the two front blades. This evacuation area always remains open, preventing any risk of bit plugging. Although the small-diameter cores rarely reach the surface intact, the large core fragments (typically larger than normal drilling cuttings) are collected at the surface for analysis.

Accurate Pipe Tallies

The Laser Pipe Tally System by Digi-Tally provides a mobile field pipe-tally system for use at the job site, in pipe yards, or in manufacturing facilities. The length of each pipe joint is measured with an advanced Class II eye-safe laser, and the data are processed on a mobile field controller. The unit rests on the pipe with an alignment support and is equipped with a top-thread locator for threads-off joint tallies (Fig. 7) or a pipe-end locator for threads-on tallies. The visible red laser spot is bright and visible on the target at the far end of the pipe. The mobile field controller can be hand held, supported by a belt retractor, or mounted to the laser unit. After performing the tally, a complete text-based report can be printed, viewed, and saved electronically for reference. Only one instrument is needed for pipe longer than 100 ft, with a measurement accuracy of 0.005 ft. Pipe length can be read without removing conventional stripping. An autodetection system alerts operators about potential length anomalies when generating reports.

Hydrogen Sulfide Scavengers

Hydrogen sulfide (H2S) occurs naturally in all crude oils, and it is formed during the refining process. There are many safety hazards associated with H2S, and it has detrimental effects on equipment, so it is important to treat it effectively. It is highly corrosive and can degrade process and storage equipment, leading to costly repairs. The Oilfield Technology Group of Momentive Specialty Chemicals provides fluid-performance additives and H2S scavengers. H2S scavenger products are effective for crude oil, natural gas, liquefied petroleum gas, and steam-­assisted gravity-drainage processes. Typical treatments occur at the wellsite, on production platforms, in ships, in pipelines, and at refineries.