Real-time downhole estimation of inclination and azimuth is desirable for improved wellbore quality, better management of the drilling process with regard to wellbore hydraulics and drilling dynamics, and is a prerequisite for advanced directional drilling services such as downhole azimuthal hold mode and surface-based automated trajectory control. However, reliable estimation of azimuth while drilling remains a challenging problem, particularly in certain orientations in harsh drilling environments. We present a detailed problem description and describe the approach used to develop a new algorithm to estimate azimuth while drilling, which offers significant improvements over existing algorithms. Such an algorithm will form the foundation for advanced drilling system automation services, such as automated trajectory drilling.
An optical fiber has been utilized to continuously acquire liquid production profiles in horizontal well in X oilfield. The results obtained from the dynamical monitoring system confirm the time-varying law of the physical property under the condition of high-water flooding, which can serve as the guidelines to explore the potential of remaining oil in high water-cut/high recovery factor oilfield.
Usually, the sound wave shows different propagation speeds in different medium, which is the basic principle of this test. Firstly, optical cable is used for sound wave detection and signal demodulation.Meanwhile, a series of other processes are applied to calculate the sound velocity of mixed medium; Then the volume velocity and holdup of mixed medium for each phase are determined.The measure of liquid-producing profile along the whole horizontal well has been realized in real time. Finally, numerical simulation model considering the time-varying physical properties is established based on the core flooding laboratory experiment. This result will provide guidelines for the exploration of remaining oil in the well.
The results obtained from optical fiber monitoring system during last two years show that 80% of the fluid produced from the 502-meter horizontal well is mainly contributed to the first 90-meter horizontal section. Experimental results of core flooding under excessive water flooding (2000 pore volume) indicate that the permeability is 1.4 times of the original. The results of numerical simulations considering the time-varying physical properties illustrate that there is still internal remaining oil along the horizontal well section. So, the strategy of exploiting potential oil is proposed using an accurate directional water plugging, which will decrease 10% water cut and obtain more recoverable reserves.
Based on the dynamical monitoring results of optical fiber, this paper innovatively provides the strategy of exploiting potential remaining oil in the horizontal wells, which can provide a valuable suggestion for offshore oilfield with high productivity at high water-cut stage.
Obtaining high-resolution borehole images in oil-based mud (OBM) from logging-while-drilling (LWD) tools has been made possible through the recent development of ultrasonic imaging technologies. High-resolution acoustic impedance images enable reservoir evaluation through the identification of faults and fractures, bedding and laminations, and assessment of rock fabric. This paper presents examples of high-resolution images from a 4¾-in. ultrasonic imaging tool in OBM applications and discusses their value in assessing reservoir quality.
This paper provides details of field trials of an LWD ultrasonic imaging tool for use in boreholes ranging from 5¾ to 6¾ in. High-resolution images detailing both borehole caliper and acoustic impedance in both vertical and horizontal wellbores are shown, illustrating the high level of formation evaluation now available when OBM is used. The methodology used to address the impact of tool motion on the impedance images will also be covered. The value of real-time data on borehole stability assessment will be discussed, along with additional applications made possible from the real-time data, such as wellbore placement enhancement.
Both real-time and recorded data from field trials show the potential applications for the ultrasonic imaging tool. High-resolution impedance images covering different formations and lithologies show bedding planes and laminations and enable the calculation of stratigraphic dip, while the identification and assessment of fractures show the potential to aid operators during the development of their hydraulic fracturing program. Borehole caliper and shape assessment in real time can be used to modify the drilling parameters and to adjust mud weight, while providing an input into geomechanics assessment.
The LWD logs presented illustrate the factors that influence data quality and the methodology used to ensure high-resolution images are available in both vertical and high-angle wellbores using OBM. A direct comparison between data acquired while drilling and while re-logging sections is shown, highlighting the repeatability of the measurement while also illustrating the impact of time-since-drilled on the borehole. A comparison with wireline measurements highlights the potential for using the high-resolution LWD images as an alternative to wireline, where cost and risk of deploying the wireline may be high.
The ability to collect high-resolution images in OBM in wellbores ranging from 5¾ to 6¾ in. ensures that increased reservoir characterization is possible, leading to significant improvements in determining the viability of unconventional and other challenging reservoirs. The high-resolution amplitude images are comparable with those available on wireline technologies, and the real-time application of borehole size and shape for input into wellbore stability and geomechanics analysis ensures that common drilling hazards can be avoided.
JPT Technology Minute Poll: To Which of the Top Five UN Sustainability Development Goals Do You Think the Oil and Gas Industry Will Contribute the Most? The papers identified in the article cover sustainable development of oil and gas resources in various aspects. Flaring and emissions challenges have recently made news headlines around the world. The goal of this article is to engage you with this important topic by presenting a selection of recent SPE papers which address these challenges through various approaches. Operators face a dilemma in balancing the need for mud weight (MW) to remain below the fracture gradient to avoid losses, while also providing sufficient density to block influxes into the well. JPT Technology Minute Poll: Which Technology Would You Choose for Offshore Compression?
Leaders from two large US onshore rig contractors said their expectations that the rig-count slide would hit a second-quarter bottom were off and are now refraining from making new predictions as to when it will end. Moving their directional drillers into their Houston real-time remote operations centers has improved drilling efficiency for two of the top shale producers. Regulators say the blowout that killed five workers on a Patterson-UTI rig in Oklahoma was the product of a slow-moving series of missed signals, misleading testing, and miscalculations that failed to control a natural gas influx. The biggest drilling company appears interested in becoming the most innovative. It is testing inventions ranging from a blowout preventer that is not hydraulically powered to power systems designed like a hybrid car.
Directional drilling is defined as the practice of controlling the direction and deviation of a wellbore to a predetermined underground target or location. This section describes why directional drilling is required, the sort of well paths that are used, and the tools and methods employed to drill those wells. Field developments, particularly offshore and in the Arctic, involve drilling an optimum number of wells from a single platform or artificial island. Directional drilling has helped by greatly reducing the costs and environmental impact of this application. A well is directionally drilled to reach a producing zone that is otherwise inaccessible with normal vertical-drilling practices.
Geosteering has relied on manual log interpretation for decades. This paper outlines a new, patent-pending method of automated geosteering dubbed Cybersteering. By utilizing a graph database spatially and assessing the quality of gamma matching for a large catalog of potential segments of constant bed dip (strat blocks), a geosteer can in many cases be constructed that closely mimics that of a manual steer. The Cybersteering proof of concept has the ability to lighten geosteering workloads while increasing productivity and accuracy of geosteers.
Geosteering as a system and method for controlling a wellbore based on downhole geological measurements to stay within a pay zone originally rose to prominence in US onshore drilling in the late 1980s and early 1990s (Lesso, Jr.). Wells came to be steered with gamma ray once logging-while-drilling and measurement-while-drilling tools became more common, although steering based off of rate of penetration and mud samples was also common. Innovations since then have included the utilization of resistivity logs, various uses of seismic data, as well as experimentation with technologies such as mass spectrometry and x-ray diffraction (Durham). However, there has yet to be as large an advancement in geosteering as the initial move from the tedious analysis of paper logs to software that can display data graphically. Within such software, geosteerers can stretch or squeeze gamma ray log sections to match a total vertical depth (TVD) type log from a nearby well in order to correlate a well's stratigraphic depth. The general process requires a geosteerer to review gamma and trajectory data every time a survey comes in and visually determine the best overall gamma match between wellbore and type log through the manipulation of strat blocks, which are sections of constant bed dip. The gamma match is changed and determined by manually varying strat block length and angles (Stoner). A typical geosteering screenshot is shown in figure 1.
Wellbores drilled on US land today are geosteered predominantly using total gamma ray measurements and periodic survey data. This approach results in a number of ambiguous scenarios whereby not enough data are available to make the correct interpretation decisions. It is for this reason that many horizontal wells are unknowingly in different locations from where they are reported to be both positionally and stratigraphically. Geosteering techniques employing high-quality azimuthal gamma imaging and continuous inclination measurements address some of the main challenges plaguing accurate wellbore placement in the Wolfcamp A and Wolfcamp B of the Southern Midland Basin. Azimuthal gamma image examples of stratified and non-stratified bedding are related to lithofacies observed in core, bringing visibility to internal geometries and demonstrating how depositional environment influences tool response from a gamma radiation standpoint. Azimuthal gamma logged in conjunction with an accurate continuous inclination measurement to reduce TVD error enhances the benefits to geosteering interpretation and bed dip calculation, resulting in higher confidence wellbore placement. Furthermore, azimuthal gamma and continuous inclination MWD tool designs are discussed in the context of the critical elements needed for accurate and high resolution measurements.
Successful underbalanced drilling (UBD) requires downhole equipment to provide real-time information to the surface for monitoring conditions during drilling operations. Pressure while drilling (PWD) sensors have proved invaluable in every UBD operation to date, when they have been included in the drillstring and operated without downtime. However, quite a number of these sensors have proved problematic, because of the vibration problems and fast drilling rates encountered with UBD. The most common technique for transmitting measurement while drilling (MWD) data uses the drilling fluid pumped down through the drillstring as a transmission medium for acoustic waves. Mud-pulse telemetry transmits data to the surface by modifying the flow of mud in the drillpipe in such a way that there are changes in fluid pressure at surface.
Baker Hughes drilled one horizontal well for major Indian operating company in a, low resistivity contrast field, onshore India. The candidate field / basin is a proved petroliferous basin, located in the northeastern corner of India.
The scope of work for this project involved integrating geological and open hole offset parameters to build a Geosteering model. Integrated data included a study of offset well data from the field, regional and local dip analysis from wellbore images, and a review of structural maps. Successful integration of these data helped to steer the well in the desired zone as per plan and make the best use of the data and to reduce uncertainties in Geosteering, drilling. Although high-quality 16-sector images commonly yield bedding dip, fracture and other geological information, this paper emphasizes how real-time reservoir navigation decisions was made using Geosteering modelling, real-time image processing, dip picking study etc.