Changes

[[file:applying-gravity-in-petroleum-exploration_fig15-14.png|left|300px|thumb|{{figure number|3}}Synthetic model of the configuration of a theoretical drawdown gas cone around a producing well, modeled after the Prudhoe Bay field, Alaska. Copyright: ARCO Exploration and Production Technology.]]

[[file:applying-gravity-in-petroleum-exploration_fig15-14.png|left|300px|thumb|{{figure number|3}}Synthetic model of the configuration of a theoretical drawdown gas cone around a producing well, modeled after the Prudhoe Bay field, Alaska. Copyright: ARCO Exploration and Production Technology.]]

One of the most attractive aspects of borehole gravity applications is its ability to detect [[Fluid contacts|gas, oil, and water contacts]] at large distances from the borehole. It can do this through multiple casing strings and formation damage—conditions where the neutron density tool performs poorly. In many hydrocarbon reservoirs, the oil has a gas cap. Frequently, these reservoirs have an underlying water zone. The shape of these interfaces over time is critical to production strategy. Methods can determine where those contacts exist in the well-bore, but only borehole gravity can determine their shape away from the well. Because the interfaces are mobile with time, their movement can be monitored with borehole gravity.

One of the most attractive aspects of borehole [[gravity]] applications is its ability to detect [[Fluid contacts|gas, oil, and water contacts]] at large distances from the borehole. It can do this through multiple casing strings and formation damage—conditions where the neutron density tool performs poorly. In many hydrocarbon reservoirs, the oil has a gas cap. Frequently, these reservoirs have an underlying water zone. The shape of these interfaces over time is critical to production strategy. Methods can determine where those contacts exist in the well-bore, but only borehole gravity can determine their shape away from the well. Because the interfaces are mobile with time, their movement can be monitored with borehole gravity.

[[:file:applying-gravity-in-petroleum-exploration_fig15-14.png|Figure 3]] shows a synthetic model of the configuration of a theoretical drawdown gas cone around a producing well, modeled after the Prudhoe Bay field, Alaska. Since so little is known about the shape of gas coning, present logging methods can severely underestimate the true [http://www.glossary.oilfield.slb.com/en/Terms.aspx?LookIn=term%20name&filter=gas-oil%20contact gas-oil contact] in the reservoir away from wells. [[Borehole gravity]] can determine the shape of the gas cone as well as locate the true gas-oil contact at a distance from the producing wells. Logs A, B, and C correspond to different gas cones shown in the model.

[[:file:applying-gravity-in-petroleum-exploration_fig15-14.png|Figure 3]] shows a synthetic model of the configuration of a theoretical drawdown gas cone around a producing well, modeled after the Prudhoe Bay field, Alaska. Since so little is known about the shape of gas coning, present logging methods can severely underestimate the true [http://www.glossary.oilfield.slb.com/en/Terms.aspx?LookIn=term%20name&filter=gas-oil%20contact gas-oil contact] in the reservoir away from wells. [[Borehole gravity]] can determine the shape of the gas cone as well as locate the true gas-oil contact at a distance from the producing wells. Logs A, B, and C correspond to different gas cones shown in the model.