Ni X.-M.,Henan Polytechnic University |
Yu Y.-Y.,Henan Polytechnic University |
He J.-Z.,Huabei Oilfield
Meitan Xuebao/Journal of the China Coal Society | Year: 2016
Gel breaking experiments about four different acid solutions were conducted, the fracturing fluid viscosity, residue particle size distribution, residua content and sugar content in the gel breaking liquid were separately tested by rotational viscometer, Malvern laser particle size analyzer, centrifuge and spectrophotometer, and the breaker for the low temperature coal reservoir was optimized. The damage ratio of gel breaking liquid to the coal reservoir was evaluated by experimental tests. The results show that: Hydroxyropyl-guar gum fracturing fluids could be broken quickly and completely at the temperature 20 degrees by using the HXM+NH4Cl, the greater the concentration, the faster the gel breaking speed; When the concentration is 0.10% HXM+0.05%NH4Cl, the fracturing fluid viscosity can drop less than 5 mPa·s within 2 hours, the residue particle size is 86 μm, residue content is 70 mg/L. The damage ratios of permeability by coal samples are lower than 20% when the original permeability is less than 0.87×10-15 m2. Furthermore, the higher the original reservoirs permeability, the greater the damage ratio is. Compared with the oxide breaker, the advantages of the composite acid breaker are quite torn glue at low temperature, little residual content and the minor injury. © 2016, Editorial Office of Journal of China Coal Society. All right reserved.
Zhang M.,Sinopec |
Jia S.,Sinopec |
Cheng G.,Petrochina |
Liu Z.,Petrochina |
Gong H.,Huabei Oilfield
Well Testing | Year: 2012
For carbonate rock, fracturing stimulation and reformation is one of main increasing production measures. Through many years prac tice, five types of acid fracturing string had been taken formed which are blank pipe string, mechanic single seal, hydraulic pressui setting, hydraulic pressure single seal and double packer of cased or open hole. In which, hydraulic pressure single seal and doubl packer of cased or open hole are two of the new acid fracturing string , the former is much economic, reliability of operation string i high, and the later one, whose setting process is much efficient, can stick or seal water layers to realize separated layer reformation t achieve acid fracturing purpose.
Yubin H.,Bohai Drilling and Exploration Corporation |
Yayong C.,Bohai Drilling and Exploration Corporation |
Zengxian H.,Bohai Drilling and Exploration Corporation |
Ru L.,Bohai Drilling and Exploration Corporation |
And 2 more authors.
Well Testing | Year: 2010
According to situation of down hole operation without drilling platform BOP , structure, principle and applied method of several BOP device is introduced in detail. Advantages and disadvantages of several blowout preventer device are analyzed by examples indicating the assembly C does not meet the on-site operation, and preventing method by multi-function devices BOP is recommended which has advantages of being convenient, safe and reliable, and saving time and labor.
Liu M.,Huabei Oilfield |
Xiong L.,Huabei Oilfield |
Zhao F.,Huabei Oilfield |
Sun W.,Huabei Oilfield |
And 3 more authors.
Drilling Fluid and Completion Fluid | Year: 2014
The well Wen 23-6J is a relief well for the well Wen 23-6x, aimed at ensuring the sealing capacity of the reservoir cap rock formation. The well Wen 23-6J was planned to be directed to the well Wen 23-6x by drilling beneath the bottom of the fish, and then spot cement slurry through the relief well to plug the Wen 23-6x. To realize the connection of the two wells, the 3rd interval of the relief well was sidetracked four times at different depths to drill five laterals, with the minimum center distance between two holes less than 20cm. In these depths, long sections of claystones, which are water sensitive and soft, exist in the Minghuazhen-Dongying formations. The Shahejie formation is also water sensitive and borehole instability has been encountered in the past. Another problem is lost circulation, which has been encountered in the Shihezi formation. A modified polymer sulfonate drilling fluid was used during drilling. A salt-resistant filtrate reducer Redul, a non-fluorescent shale inhibitor CFF-1 and a non-fluorescent white asphalt NFA-25 were introduced to prevent borehole wall from collapsing by enhancing the sealing and plugging capacity of the drilling fluid. The mud properties were carefully maintained during drilling. Lone period of exposing of open hole to drilling fluid left no downhole problem and the drilling operation was successful.