Layer | Fill | Outline |
---|
Map layers
Theme | Visible | Selectable | Appearance | Zoom Range (now: 0) |
---|
Fill | Stroke |
---|---|
Collaborating Authors
Results
Abstract Horizontal wells can be effective alternatives to fractured vertical wells in low permeability reservoirs by increasing economically recoverable gas. Given this potential, simple but reliable methods for determining potential, simple but reliable methods for determining the production performance of horizontal wells must be available. To aid in these forecasts, production type curves were developed. These curves can be used to predict the production of horizontal wells during predict the production of horizontal wells during preliminary evaluations, thus avoiding the need for costly and preliminary evaluations, thus avoiding the need for costly and time consuming computer simulations. The effects of vertical-to-horizontal permeability, and the ratio of the horizontal well length to the length of the reservoir are also discussed. Application of the curves is illustrated using pre-stimulation production data from a horizontal well drilled into a tight gas-bearing formation. Forecasted gas production using the type curves closely matches the field data and demonstrates their utility. Introduction Interest in and use of horizontal wells to produce crude oil and natural gas have increased in recent years, with significant production increases being reported. In addition to producing wells, other horizontal well projects are being considered for implementation in various projects are being considered for implementation in various reservoirs. 3 Using horizontal well technology to stimulate production from hydrocarbon reservoirs is not a new idea." however, significant advances in drilling technology and improvements in operating procedures during the last decade have resulted in substantial cost reduction for horizontal well projects. Most horizontal drilling has targeted oil-bearing formations, although tremendous potential exists for their use in tight gas-bearing reservoirs. Low permeability formations contain a considerable natural gas resource, which is difficult to produce; thus these formations remain uneconomical. Developing this resource requires innovative approaches to improve extraction efficiency. one such technology is the use of horizontal wells. A horizontal well can be considered a directionally controlled, infinite-conductivity, partially-penetrating vertical fracture. The orientation and length of the well are determined by the operator. With vertical fractures, the orientation, wing length, and conductivity are determined by in-situ stresses, fracturing fluid rheology, and proppant type. Furthermore, induced fractures have finite-conductivity. In contrast, present technology makes It possible to drill horizontal present technology makes It possible to drill horizontal wells, which are much longer than fracture half lengths. that can be created at moderate costs. Although horizontal wells can be surrogates for fractured vertical wells, even a long horizontal well may not outperform a fractured vertical well in some cases Ultimately, the decision to use a horizontal well, rather than a stimulated vertical well. must be based on technical and economic feasibility evaluations. One important variable to consider when evaluating horizontal wells is the accurate prediction of production rates. Computer modeling is widely used to provide these production forecasts during project planning. The objective of this study was to develop and evaluate production type curves for horizontal wells producing from production type curves for horizontal wells producing from low permeability natural gas reservoirs. These type curves can be used to predict horizontal well production during initial evaluations. however, where a narrow range exists between an economically successful or unsuccessful project, detailed engineering calculations should be part of the well prognosis. In addition to developing the curves, various aspects affecting the performance of horizontal wells were reviewed. These included (1) the length of a horizontal well compared to the extent of the reservoir limit, and (2) vertical and horizontal permeability influences.
- North America > United States > West Virginia > Appalachian Basin > Huron Shale Formation (0.99)
- North America > United States > Virginia > Appalachian Basin > Huron Shale Formation (0.99)
- North America > United States > Kentucky > Appalachian Basin > Huron Shale Formation (0.99)
Abstract Type curves have been developed for horizontal wells producing from low permeability gas reservoirs. The producing from low permeability gas reservoirs. The general solutions are presented in terms of dimensionless cumulative production and dimensionless time and are grouped based on two other dimensionless variables, the wellbore radius and well length. The type curves were developed using the solutions to flow problems, which were determined using a finite-difference reservoir model. This paper includes a detailed account of the methodology used and comparisons of supporting simulation results to other, general flow solutions that have been previously reported. Issues concerning the production performance of horizontal wells in anisotropic media are also discussed. The curves can be used to initially predict the performance of horizontal wells, thus avoiding the need performance of horizontal wells, thus avoiding the need for costly and time consuming computer simulation. Introduction Interest in and use of horizontal wells to produce crude oil and natural gas have increased significantly in recent years. Areas where horizontal wells have been drilled and the production of hydrocarbons underway include Prudhoe Bay, the Wyoming Overthrust (Dakota), Rospo Mare, and, in the case of gas, eastern Devonian shales. The technological and economic accomplishments of these projects have been reported in addition to planned or initiated horizontal well drilling and completion projects. Given this interest, and the fact that horizontal wells are viable alternatives to vertically fractured wells, the need exists to understand fluid flow and production performance of horizontal completions. performance of horizontal completions. Horizontal wells represent a limiting case of a vertically oriented, hydraulically fractured well, that is, a partially penetrating vertical fracture. Mutalik, et al., discuss and compare horizontal and vertically fractured wells in terms of dimensionless skin factors. They also cite other documented comparisons of vertically fractured wells and horizontal wells. In contrast to vertical wells that have been stimulated by hydraulic fracturing, unstimulated horizontal wells are drilled to direct the path of the wellbore and can achieve very high conductivities within the well. Vertical fracture orientations are determined by in situ stresses where the induced crack is aligned parallel to the maximum principal stress. However, in the case of horizontal wells, the path of the borehole is determined by the operator/driller. A second difference concerns the conductivity of the flow paths. In the case of a vertically fractured well, the existing finite conductivity is dictated by fracture geometry, proppant type and distribution, and closure pressure. proppant type and distribution, and closure pressure. Conversely, a horizontal well is an infinite conductivity conduit that links the formation to the fluid delivery systems. In addition, while horizontal wells can be many hundreds to more than 2,000 feet (more than 650 meters) in length, long, effective half-lengths have been difficult to achieve in typical, vertically fractured wells. Many type curves have been developed for vertically fractured wells to analyze pressure behavior and predict production. Most of these "generic solutions" predict production. Most of these "generic solutions" have been utilized in the analysis of pressure transient tests to evaluate stimulation effectiveness and to determine formation characteristics, e.g., formation permeability. Production type curves (where a constant permeability. Production type curves (where a constant bottomhole flowing pressure is assumed) have also been developed and used to predict production without the need for expensive computer simulation. The curves developed for the National Petroleum Council's (NPC) 1980 study of natural gas resources are one example of these. Since horizontal wells have proved to be viable alternatives to vertically fractured wells, it is desirable to develop production type curves for horizontal wells. P. 605
- North America > United States > Alaska > North Slope Borough > Prudhoe Bay (0.24)
- North America > United States > Wyoming (0.24)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.34)
- Geology > Geological Subdiscipline > Geomechanics (0.34)