刘锋,张晓飞,胡维首,王思凡,任晓宇,蔡楠. 鄂尔多斯下古碳酸盐岩气井绒囊修井液稳气控水技术[J]. 石油钻采工艺,2021,43(3):400-404. DOI: 10.13639/j.odpt.2021.03.020
引用本文: 刘锋,张晓飞,胡维首,王思凡,任晓宇,蔡楠. 鄂尔多斯下古碳酸盐岩气井绒囊修井液稳气控水技术[J]. 石油钻采工艺,2021,43(3):400-404. DOI: 10.13639/j.odpt.2021.03.020
LIU Feng, ZHANG Xiaofei, HU Weishou, WANG Sifan, REN Xiaoyu, CAI Nan. Fuzzy-ball workover fluid based gas stabilization and water control technology for the gas wells in the Lower Paleozoic carbonate reservoirs of the Ordos Basin[J]. Oil Drilling & Production Technology, 2021, 43(3): 400-404. DOI: 10.13639/j.odpt.2021.03.020
Citation: LIU Feng, ZHANG Xiaofei, HU Weishou, WANG Sifan, REN Xiaoyu, CAI Nan. Fuzzy-ball workover fluid based gas stabilization and water control technology for the gas wells in the Lower Paleozoic carbonate reservoirs of the Ordos Basin[J]. Oil Drilling & Production Technology, 2021, 43(3): 400-404. DOI: 10.13639/j.odpt.2021.03.020

鄂尔多斯下古碳酸盐岩气井绒囊修井液稳气控水技术

Fuzzy-ball workover fluid based gas stabilization and water control technology for the gas wells in the Lower Paleozoic carbonate reservoirs of the Ordos Basin

  • 摘要: 鄂尔多斯盆地下古碳酸盐岩气井投产后地层压力系数降低,修井时地层气体上窜与井筒流体漏失多发,需封堵地层实现安全作业;部分地层产水损害产气能力,同时具有控水需求。利用封堵性绒囊修井液携带可增大气、水流动阻力差的表面活性剂进入低压气层,将传统伤害控制转换为地层稳气控水。实验压制直径38 mm、长30~100 cm的填砂管模拟下古碳酸盐岩地层,测定注入绒囊修井液至出口返出时驱压4.59~16.18 MPa,重复注入清水驱压增幅7.04~18.22 MPa,与绒囊修井液充填半径成正比。4种长度填砂管中注入破胶剂加速返排后,相同驱压注入氮气180 min后渗透率恢复率较地层水高2.02%~6.07%,且恢复率差值与充填半径成正比。现场4口气井地层中绒囊修井液充填半径2.12 m升至8.97 m,地层承压强度从17 MPa升至21 MPa,作业前后90 d内日产水降幅与日产气降幅的差值由18.68%升至62.90%。结果表明,下古碳酸盐岩气层中绒囊修井液暂堵强度与控水效果均与流体充填半径成正比,可实现修井暂堵与稳气控水再利用。

     

    Abstract: After the gas wells in the Lower Paleozoic carbonate reservoirs of the Ordos Basin are put into production, the formation pressure coefficient decreases. And in the process of well workover, reservoir gas channeling and wellbore fluid loss happen frequently. Therefore, it is necessary to plug the reservoirs, so as to ensure safe operation. In some reservoirs, gas production capacity is damaged by water production while water control is needed. Plugging fuzzy-ball fluid was adopted to carry the surfactant which can increase gas-water flow resistance difference into low-pressure gas reservoirs, to transform the traditional damage control into the gas stabilization and water control. In the experiment, a sand packed tube (diameter 38 mm and length 30-100 cm) was prepared to simulate the Lower Paleozoic carbonate reservoirs. The measurement results show that the displacement pressure is 4.59-16.18 MPa when the injected fuzzy-ball fluid flows to the outlet and it is increased by 7.04-18.22 MPa after repetitive fresh water injection, which is in proportion to the filling radius of fuzzy-ball fluid. Gel breaker is injected into sand packed tubes with four lengths to speed up the flowback. After nitrogen is injected under the same displacement pressure for 180 min, the permeability recovery ratio is 2.02%-6.07% higher than the formation water and the recovery ratio difference is in proportion to the filling radius. In four gas wells, the filling radius of fuzzy-ball fluid in the reservoirs increases from 2.12 m to 8.97 m, the formation bearing strength rises from 17 MPa to 21 MPa. The difference between daily water production decrease ratio and daily gas production decrease ratio rises from 18.68% 90 days before the operation to 62.90% 90 days after the operation. It is indicated that the temporary plugging strength and water control effect of fuzzy-ball fluid in the Lower Paleozoic carbonate reservoirs are both in proportion to the filling radius. Furthermore, fuzzy-ball fluid is conducive to the realization of temporary plugging and gas stabilization and water control in the process of well workover.

     

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