Why horizontal drilling

Estimating horizontal well productivity. Horizontal well applications in steamflooding. Steam assisted gravity drainage. Campbell, T. Deliquification of Horizontal Wells. Miskimins, Jennifer L. Matar, Omar K. Help with editing Content of PetroWiki is intended for personal use only and to supplement, not replace, engineering judgment. Horizontal Drilling Comes of Age.

Oil Field Review 2 3 : SPE Drill Eng 7 2 : Categories : 1. Navigation menu Personal tools Log in. The total well length is 2, meters and the horizontal section measures 1, meters. Advanced data collection and geophysical survey was conducted through the entire horizontal phase. The well was spudded on January 15, , by the semisubmersible rig Transocean Spitsbergen and the well test was finalized end of March Published October 10, For your recommendation a second click is necessary.

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OMV Share. If a rock unit is fifty feet thick, a vertical well drilled through it would have a pay zone that is fifty feet in length. However, if the well is turned and drilled horizontally through the rock unit for five thousand feet, then that single well will have a pay zone that is five thousand feet long - this will usually result in a significant productivity increase for the well.

When combined with hydraulic fracturing , horizontal drilling can convert unproductive shales into fantastic reservoir rocks. Fractured reservoir: Some reservoirs have most of their pore spaces in the form of fractures. Successful wells must penetrate fractures to have a flow of natural gas into the well. In many geographic areas there is a dominant fracture direction along which most of the fractures are aligned.

If the well is drilled perpendicular to the plane of these fractures, then a maximum number of fractures will be penetrated. This is done by drilling in a direction that intersects a maximum number of fractures. The drilling direction will normally be at right angles to the dominant fracture direction. Geothermal fields in granite bedrock usually get nearly all of their water exchange from fractures. Drilling at right angles to the dominant fracture direction will drive the well through a maximum number of fractures.

If a well is out of control, a "relief well" can be drilled to intersect it. The intersecting well can be used to seal the original well or to relieve pressure in the out-of-control well. Horizontal drilling has been used to install gas and electric lines that must cross a river, cross a road, or travel under a city. Relief well: If a well has a problem and begins to flow out of control, it must be sealed at depth or the pressure must be relieved.

In this situation a "relief well" can be drilled from a nearby site. The relief well will be a directionally drilled well that intersects the bore of the problem well to drain off some of the pressure or to plug the well by pumping cement into the bore. Vertical wells can effectively drain rock units that have a very high permeability.

Fluids in those rock units can flow quickly and efficiently into a well over long distances. However, where permeability is very low, fluids move very slowly through the rock and do not travel long distances to reach a well bore. Horizontal drilling can increase the productivity in low-permeability rocks by bringing the well bore much closer to the source of the fluid.

Utility line: Utility service lines such as those delivering electricity, water, or natural gas are sometimes installed by directional drilling.

This method is used when they must cross a road where excavation would disrupt traffic, cross a river where excavation is impossible, or transverse a community where surface installation by excavation would be extremely expensive and disrupting. Perhaps the most important role that horizontal drilling has played is in development of the natural gas shale plays. These low-permeability rock units contain significant amounts of gas and are present beneath very large parts of North America.

In these rock units the challenge is not "finding" the reservoir; the challenge is recovering the gas from very tiny pore spaces in a low-permeability rock unit. To stimulate the productivity of wells in organic-rich shales, companies drill horizontally through the rock unit and then use hydraulic fracturing to produce artificial permeability that is propped open by frac sand.

Done together, horizontal drilling and hydraulic fracturing can make a productive well where a vertical well would have produced only a small amount of gas. Most horizontal wells begin at the surface as a vertical well. Drilling progresses until the drill bit is a few hundred feet above the target rock unit. At that point the pipe is pulled from the well and a hydraulic motor is attached between the drill bit and the drill pipe. The hydraulic motor is powered by a flow of drilling mud down the drill pipe.