[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090288833%22.PGNR.&OS=DN/20090288833&RS=DN/20090288833 US20090288833A1] titled "System and methods for constructing and fracture stimulating multiple ultra-short radius laterals from a parent well" by Halliburton. Hydrocarbons are often dispersed in a stacked sequence in the reservoir. The reservoir also contains water bearing zones. Conventional equipment cannot be used for drilling and stimulation of multi lateral well as they are very time consuming, and expensive in nature. It provide a systems and methods for constructing '''multiple ultra-shot radius laterals''' from a parent well and stimulating the subterranean zones intersected by multiple lateral wellbores extending outwardly from one or more parent wellbores by injecting a stimulation fluid into the lateral wellbores; and stimulating the zones intersected by the lateral wellbores.
[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7278486.PN.&OS=PN/7278486&RS=PN/7278486 US7278486B2] titled "Fracturing method providing simultaneous flow back" by Halliburton. The top down completion method has several drawbacks:
-a larger ID tubing is required for the fracturing fluid to be pumped down the tubing which is difficult to handle in the wellbore compared to smaller pipe sizes (1.5-2.0 inch diameter) and is more expensive.
-previously placed fracturing fluid is produced up the annulus, which impinges against the tubing string and therefore can cause damage to the tubing string.
- the previously fractured zones are above the packer and flowing these zones back may result in proppant building up on the top of the packer.
Method of fracturing a multi-zone subterranean formation utilizes bottom up approach comprising, the steps of first perforating the pay zone by injecting a hydraulic fluid into the subterranean formation through the jet ports of the hydra jetting sub and isolating this pay zone from the adjacent pay zone using packers by moving the having a bottom-hole assembly ("BHA") downhole below the zone, second is fracturing by pumping the fracturing fluid down an annulus formed between the wellbore and a tubing string and then flowing back the fracturing fluid to the surface through the BHA and tubing string. The second zone to be treated next is above this treated zone.
[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=6119776.PN.&OS=PN/6119776&RS=PN/6119776 US6119776A] titled "Methods of stimulating and producing multiple stratified reservoirs" by Halliburton. The production of hydrocarbons from multiple stratified hydrocarbon reservoirs has been a low economic return venture for oil and gas exploitation companies because
-the hydrocarbons are contained in numerous relatively small reservoir compartments, many of which cannot be practically or economically penetrated by well bores.
-the reservoir formations containing the hydrocarbons have relatively low permeabilities.
Methods of stimulating and producing multiple stratified hydrocarbon reservoirs having '''numerous separate reservoir compartments''' are provided.
-It comprise steps for the drilling a first well bore into a lower part of the reservoir having a horizontal portion which intersects a previously drilled second well bore therein. Fracture is formed extending into two or more reservoir compartments from the horizontal portion of the third well bore for conducted hydrocarbons in the reservoir into the horizontal portion of the first well bore from where the hydrocarbons flow into the second well bore and are withdrawn.
[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7001872.PN.&OS=PN/7001872&RS=PN/7001872 US7001872B2] titled "Subterranean formation treating fluid and methods of fracturing subterranean formations" by Halliburton. Use of high viscous fluids as a fracturing fluid, containing gelling and crosslinked agent, show some serious problem such as
-For maintaining the viscosity of fluid, the concentration of the gelling agent may be increased, which results in, increased costs and pumping of the fracturing fluids more difficult.
- Sometimes, the filter cake produced from the fluid on the walls of well bores shows difficulty in cleanup.
- Higher operating and fixed cost as they required expensive metering devices and other similar equipment.
Improved method for treating subterranean well formations, by using treating fluid concentrates which comprise of water, '''fully hydrated depolymerized polymer''' and a crosslinking agent.
-gelling agent are replaced by depolymerized polymer and these fluid are less viscous in nature.
===Schlumberger===
