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Abstract Thrust bearings used in mud lubricated drilling motors have to handle high loads, abrasive drilling mud, and large impacts, all of which reduce bearing life. In bent housing motors used for directional drilling, these adverse operating conditions are amplified and generally result in severely shortened bearing life and reliability. When drilling the lateral section with a bent housing motor a shorter "bit-to-bend" length is a great advantage because it reduces the loads on many of the motor components. Through the use of a resiliently-mounted stacked ceramic bearing design, the thrust bearing length can be reduced while retaining the capability to handle the increasing thrust and impact loads and withstand the erosion from abrasive drilling muds, thus increasing life expectancy and reliability. The patented ceramic stack bearing has been designed to replace ball and PDC bearings in mud lubricated drilling motors. Although the bearing can be used in any drilling motor, a significant advantage is realized from using the shorter bearing design for short bit-to-bend motors. The increasing demand for short bit-to-bend motors has led manufacturers to reduce the length of their bearing section, and thus the life and load capacity of the thrust bearing. A shorter conventional thrust bearing stack means the load is carried by fewer bearing components and thus the load-per-bearing stage is increased, reducing the life expectancy of the bearing and, in turn, limiting the drilling hours a motor can continuously operate. With the increasing number of directional wells being drilled, short bit-to-bend motors have become more desireable; more drilling companies are requesting them and more motor manufacturers are designing them. Using the improved bearing technology, combined with short bit-to-bend mud motors, directional drillers are able to drill curved and lateral sections of wells with one motor. This eliminates tripping out of the well to change the motor / BHA (Bottom Hole Assembly). Deep wells in the Eagleford formation have saved days of drilling time by operating motors in excess of 280 hours continuously with this resiliently mounted ceramic thrust bearing assembly.
Abstract Shale gas reservoirs are quickly becoming an important source for natural gas. Historically, the shale basins were not looked at for economic production because of their very low permeability values. However, with the use of hydraulic fracturing combined with horizontal well completions, shale plays have become economically producible, especially the Marcellus shale. In order for these wells to produce, hydraulic fracturing must be employed. This technique makes production viable, but it also changes the in-situ stress field, through the fracture itself and the increased production that occurs. This change in the stress field can damage the wellbore and compromise the integrity of the casing. In this study, geomechanic and reservoir models were constructed using commercially available software to study the change of the stress field in the formation. The parameters of the hydraulic fracture were varied to study the effects of the hydraulic fracture half length and the fracture permeability on the stress field, specifically near the wellbore.
- North America > United States > West Virginia (1.00)
- North America > United States > Virginia (0.90)
- North America > United States > Pennsylvania (0.90)
- (3 more...)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (1.00)
- Geology > Petroleum Play Type > Unconventional Play > Shale Play > Shale Gas Play (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
Abstract Bearings used in directional drilling operate in conditions which are significantly more severe than those found in traditional industrial applications. One of the most difficult conditions mud motor thrust bearings encounter is misalignment, which is amplified in bent housing motors. The purpose of fixed bend and adjustable bend motors is to build a desired angle in a well. To accomplish this build rate the housing is manufactured with a purposely bent joint which typically deviates between 1 to 3 degrees from the rest of the bottom hole assembly. Radial bearing wear creates uneven thrust bearing loading due to angular misalignment. Uneven loading in ball bearings results in significantly higher Hertzian stresses which reduces bearing life and reliability. Uneven loading in diamond, or PDC, bearings results in premature failures due to increased stresses and chipping. The proposed paper will demonstrate that a thrust bearing design incorporating independent and resiliently mounted thrust pads operating against a continuous rotating bearing surface is effective at handling misalignment in bent housing mud motors.
- Well Drilling > Drilling Equipment (1.00)
- Well Drilling > Drilling Operations > Directional drilling (0.92)
Abstract New and unconventional reserves are now being developed in more isolated and remote locations by drilling extended-reach horizontal wells (ERWs). The complexity of designing tubulars for ERHWs depends on the well objectives, targetโs location and wellbore trajectory. Tubular design must be compatible with the intended wellbore trajectory to minimize the downhole dynamic events such as torque and drag, buckling and vibrations. The existing dynamic models for calculating anticipated axial load and torque distribution for tubulars in ERHWs consider only the effect of the normal contact loads and frictional forces. However, lateral and torsional vibrations are critical to the tubular design for ERHWs because vibrations contribute to the total normal contact load. This study uses the unbalanced force and fluid added mass theories to quantify the magnitude of the normal contact load generated during lateral vibrations of a near-straight tubular section in an ERHW. The generalized model is developed using the knowledge of engineering mechanics to integrate axial load, torque, buckling and vibrations models. The integrated dynamic equations neglect the hydraulic effects in drilling tubulars and weight-on-bit term in completion tubulars. It was observed that the downhole dynamic events contribute a relatively higher percentage to torque transfer than they do to axial load transfer. Also, when all the downhole dynamic events occur together and the critical buckling loads have not been reached, torque and drag events contributes the major portion of the axial load transfer followed by lateral vibrations. The model equations developed in this paper are validated using the well data from one of the worldโs longest ERHWs. The calculation of axial load and torque distribution accounts for the underestimated values of loads and torque obtained from previous dynamic models. This study will lead to better drilling optimization through the minimization of failures, non-productive times, and ultimately reduced total drilling costs.
Abstract A new algorithm for processing cross-dipole acoustic log waveforms in formations with horizontal transverse anisotropy (HTI) has been developed. Conventional algorithms for anisotropy processing of cross-dipole acoustic waveforms minimize an objective function whose parameters are the azimuth angle of a reference (usually X-dipole) transmitter relative to the fast principal flexural-wave axis of the HTI formation and the fast and slow shear wave slowness. Minimizing the objective function with respect to all the parameters provides the desired anisotropy angle and the amount of anisotropy. It is common to minimize the objective function over all the parameters using a numerical search method (such as very fast simulated annealing) or by evaluating the objective function on a fine grid in the parameter space (i.e., brute force); however, this is never necessary with cross-dipole waveforms. It is possible to derive equations for the angle of the X-dipole relative to the fast principal flexural-wave axis that can be solved analytically as a function of the other parameters. Analytic computation relative to numerical computation provides several advantages. First, the angle found at any given point in the auxiliary parameter space is a mathematically exact global minimum (up to computer precision) with respect to the angle of the objective function at that point in the auxiliary parameter space. This is not guaranteed with a numerical-search algorithm. In addition, studying the objective function at the minimizing angle with respect to the remaining auxiliary parameters can provide insight as to the best means of minimizing the objective function with respect to the remaining parameters. This paper uses synthetic and field data to demonstrate the advantages of this new algorithm.
Abstract To date the most prolifically producing geologic structure in Montana's Bakken formation is the Elm Coulee Field. While the first wells drilled into this structure 35 years ago had some success, significant production did not occur until horizontal wells were drilled starting in 2000. The Bakken Petroleum System consists of three members, the Upper Bakken, shale, the Middle Bakken, silty dolostone, and the lower Bakken, siltstone. Production of the Bakken Petroleum System is extremely difficult to predict with standard reservoir models. Thus, the decision to understand initial production through geologic drivers was made. An investigation of the implications of ancient geology on what is believed to be specific areas of micro-flexures in and around the major geologic structures in Montana's Bakken three-member formation will form the basis for a Bakken production model. The challenge in modeling the Bakken's production, both initial and subsequent, stems from the unusual history matching problem of either extremely high initial production with an unpredictably low subsequent production or surprisingly low production to begin with. The authors believe this phenomenon is due to broaching a series of micro-flexures and draining them, resulting in high initial production and unsustained subsequent production, or missing these structural flexures all together resulting in low production. This paper will investigate the genesis of Montana's Bakken micro and macro fractures with the ultimate goal of simulating and thus predicting production for wells currently producing in the area.
- North America > United States > North Dakota > Mountrail County (0.52)
- North America > United States > Montana > Richland County (0.37)
- Geology > Geological Subdiscipline > Economic Geology > Petroleum Geology (1.00)
- Geology > Structural Geology > Tectonics > Plate Tectonics (0.71)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.52)
Abstract Fracture conductivity in many hydraulic-fracturing treatments can be inadequate. It is greatly affected by the concentration of the packed proppant in the fracture. Higher concentrations yield higher conductivity by virtue of a wider fracture. However, there are practical limitations to the amount of proppant that can be placed into any particular reservoir, and therefore production is often conductivity limited. An alternate approach to achieve high conductivity is to create a fracture by placing well-distributed, low-density particles characterized by a proppant concentration less than 0.1 lbm/ft. Low particle concentrations result in fractures that have high porosity and are fundamentally different from fractures with packed beds of conventional proppants. In this paper, the theoretical basis for the conductivity of these fractures is presented. A 3-D model has been developed to simulate high-porosity fractures created with these particles. Test data used to refine the model can be used to predict the conductivity of the fracture based on the porosity level, the closure stress, and the material properties. Production data from two application areas in North America are shown to highlight the benefits of using this type of fracturing proppant. A screening life cycle analysis (LCA) is included to evaluate and highlight the beneficial attributes of using a low-density proppant to achieve fractures with high conductivity. The LCA considers the impact of logistics and fracture design on the environment.
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Lifecycle > Treatment (0.47)
- North America > United States > Wyoming > Green River Basin > Jonah Field (0.99)
- North America > United States > New Mexico > San Juan Basin (0.99)
- North America > United States > Colorado > San Juan Basin (0.99)
- North America > United States > Arizona > San Juan Basin (0.99)
Abstract The emergence of the ultra-low permeability formations, such as Marcellus Shale, as a target of exploration and development has created new challenges for resource development. To achieve economic production from shale formations massive stimulation treatments are required. Horizontal wells are the most effective in providing access to the formation to perform multi-stage hydraulic fracturing treatments. The limited field experience with multiple hydraulic fractures in horizontal wells indicates that significant increase in initial production can be achieved as the number of hydraulic fractures is increased. However, the production performance, particularly over longer time periods, is not well established. The objective of this study was to analyze the production performance of multiply fractured horizontal well completed in Marcellus Shale to determine the long term production performance. The production history from a number of Marcellus Shale horizontal well in West Virginia were collected and analyzed using different commercial reservoir simulators. The impact of reservoir and hydraulic fracture parameters on the production performance and gas desorption were also investigated. The results indicated the presence of number of different flow regimes. The hydraulic fractures appear to dominate the early production performance while the later production is influenced by natural fractures. The results can be utilized to investigate the feasibility horizontal wells with multiple hydraulic fractures and optimize the production from the shale formation.
- North America > United States > West Virginia (1.00)
- North America > United States > Virginia (1.00)
- North America > United States > Pennsylvania (0.92)
Abstract A method of using surface acquired radiation data has proven successful in Kentucky's shallow oil reservoirs of the southern Illinois Basin. The theory adhered to is that measured surface radiation shows characteristic low activity above petroleum deposits when compared to surrounding areas. Mapping measured potassium data layered with total radiation data can aid in identifying pooled hydrocarbon deposits as well as the area and extent of these deposits. An overview of proper field acquisition operations is given as well as an analysis of three radiometric surveys taken in Kentucky.
- North America > United States > Kentucky > Illinois Basin (0.99)
- North America > United States > Indiana > Illinois Basin (0.99)
- North America > United States > Illinois > Illinois Basin (0.99)
Abstract Production analysis can aid in the determination of formation and stimulation characteristics including permeability, fracture half length, fracture conductivity, and completion efficiency. The time to the end of the infinite acting linear flow combined with the distance between stimulated fracture faces yields permeability. The production analysis method includes three flow regimes; infinite acting linear flow, fracture-fracture interference from evenly spaced fracture stimulation treatments which leads to boundary dominated flow and fracture-fracture interference when fracture stimulation treatments are unevenly spaced. Production for the uneven or non-uniform spacing situation can provide perforation cluster completion efficiency for plug and perf completions and can be diagnostic in packer ports systems when stimulations are originated at the packer due to packer induced rock failure. Low completion efficiencies could dictate fewer clusters per stage in future designs. If low completion efficiencies are revealed, increased isolation to maintain actual stimulated fracture face distance may be required. In packer port systems identification of non-design uneven spacing may also warrant increased isolation. Case studies from three shale reservoirs are included to illustrate the production analysis techniques.
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.72)
- Geology > Petroleum Play Type > Unconventional Play > Shale Play (0.65)
- North America > United States > Texas > West Gulf Coast Tertiary Basin > Eagle Ford Shale Formation (0.99)
- North America > United States > Texas > Sabinas - Rio Grande Basin > Eagle Ford Shale Formation (0.99)
- North America > United States > Texas > Maverick Basin > Eagle Ford Shale Formation (0.99)
- (5 more...)
- Well Completion > Hydraulic Fracturing (1.00)
- Well Completion > Completion Installation and Operations > Perforating (1.00)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics > Flow in porous media (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Drillstem/well testing (1.00)