Water and Sand Control Technology
Water and Sand Control Technology
Introduction of Water and Sand Control Technology applied in unconsolidated sandstone reservoir in the high water cut stage.
The water and sand control technology is put forward to solve problems in unconsolidated sandstone reservoir of different sand production type in the high water cut stage.
For reservoirs which product sand slightly, the newly developed water-dispersible emulsion is used to consolidate sand and reduce water cut.For reservoirs which have serious sand problems or voidage formation, high pressure filling composite emulsion sand fixation technique is put into use.In this case, the emulsion is functioned both as a sand-carrying fluid emulsion and the water control and sand-fixation agent.
Schematic diagram of principle of sand control
The water and sand control technology has the following characteristics:
(1) Dual function of "stabilizing sand" and "blocking sand"
The sand stabilization agent is a cationic polymer.
It makes free sand a great combination by taking advantage of its electrostatic adsorption, increasing the critical velocity of formation sand to stabilize sand.
The resin-coated sand forms an artificial wall by filling outside the tube, preventing the fine sand and fine sand combination flowing to the wellbore as to block sand.
Sand stabilization mechanism:
The sand stabilization agent with the positively charged branched group adsorbs fine silt sand, making it a combination of fine sand,so that the critical flow velocity of the fine silt increases.
(2) Applicable to casing deformation wells and inexpensive
Water and sand control integration technology uses a trip column, largely saving the secondary operations costs of sand control and water control.In addition, because mechanical sand control tube is unnecessary(such as screens, etc.),it is applicable in casing deformation wells.
(3) For formation with high clay content (greater than 10%), the water and sand control technology still can be used. Because the technology uses the" sand stabilization " system which can prevent swelling and control sand, it is suitable for the formation with high clay content.
A field trial was conducted in 2011 in Jiangsu Oilfield. 2 wells were implemented measures to. By February 11, 2012, the cumulative increased oil has reached 595 tons, water production has reduced by 6,641 tons . Water cut, respectively, 92.5% from the prior measures dropped to 61.5%, 93.7% down to 39.1%. Water control effect is remarkable.
The oil production of Zhou 43-6 well reached 6.9 tons at peak after measures, the lowest water content down to 25%. Until February 11, 2012, the well had produced more than two months normally. The comparison between before-measures and after-measures : the average daily production fluid had reduced from 30.4 tons to 9.1 tons; the average daily oil production had increased from 1.9 tons to 5.5 tons, comprehensive water rate had reduced from 93.7% to 39.1%. Cumulative increased oil had reached 227 tons, water production had reduced by 1,569 tons. The effect of water control of increasing oil is obvious.