Supporting techniques for completion of directional well and horizontal well

 More than 500 directional wells and cluster wells as well as more than 700 horizontal wells are drilled; the completed horizontal well is 7200m at deepest with a horizontal section as long as 1051m (as designed); the shallowest horizontal well is 126.84m at vertical depth, and the ratio of horizontal displacement to vertical depth is 3.39; Max. mud density 2.15g/cm3 and Max. rate of deviation change 1.75°/m.

Equipment and outfit:

The Company has 7 sets of logging-while-drilling tool (LWD) and 48 sets of measuring-while-drilling tool (MWD); directional well and horizontal well works could be implemented simultaneously at 55 working faces.


(1) Ultra shallow-layer thick-oil horizontal well drilling technology with straight well drilling rig: a batch of horizontal well with shallowest vertical depth are drilled domestically; this technique is applied at more than 600 wells in Xinjiang Oilfield with daily oil production as much as 3~5 times of straight wells and the economic benefit is remarkable.

(2) Deep horizontal well of high-density: XX horizontal well was drilled in 2008, the designed well total depth is 5156.3 m, mud density 2.05g/cm3, and the stratum is very complicated with drilling difficulty. This well is completed 3.5 days prior to the designed construction time limit (40 days) as the one of shortest construction period and lowest complexity time rate among three engineering test wells in this area.

(3) Overall-process underbalance drilling technology of gas-reservoir horizontal well: XX well is the fist underbalance and long-displacement horizontal well of natural gas gas reservoir in Xinjiang Oilfield, the actual drilled horizontal section is 1051.92 long, and our independently-developed downhole casing valve is employed, tri-opening overall-process underbalance drilling, oil gas enters into circulation space continuously and then treated with liquid-gas separator before ignition, thus “drilling while blowing” is realized successfully.

(4) Geological directional drilling technology in thin oil reservoir: geological direction drilling technology was applied successfully at three wells in 2009, and drilling catching rate are 95.5%, 100% and 91.1% respectively.

(5) SAGD pairing horizontal well drilling technology: The technologies such as MGT magnetic positioning system, hole deviation measurement near drilling bit, and directional drilling etc. were applied successfully in Xinjiang thick-oil borefields in 2009, thus the accurate control of SAGD pairing horizontal wellbore track is reached and the vertical space between two wells is controlled within 5±0.5m.