Hollow glass beads on drilling fluid density
With the oilfield development, often faced with difficult exploration and development, purpose layer buried depth, low formation pressure, then use under-balanced drilling more. Therefore, more and more high to the requirement of drilling fluid.In order to reduce the leakage and reservoir protection, as well as oil and gas layers in time, need of drilling fluid density is lower than 1.0 g/cm3. With air drilling, foam drilling fluid, and water-in-oil emulsion drilling fluid, the realization of the oil-base drilling fluid is easy way, but there are many shortcomings, and drilling fluid performance itself control difficult, rheology and hydraulics calculation complex practical problems such as difficult to solve. Using high-performance glass beads in under-balanced drilling has many advantages. Adding glass beads of the drilling fluid density decreased significantly, and the added amount, the lower the density of drilling fluid.When the content of T60 type glass beads was 40%, 0.870 g/cm3 density of drilling fluid. Therefore, its biggest advantage is to adjust drilling fluid density within a certain scope. Instant in high pressure high, the drilling fluid density is more stable, this is because the hollow glass beads with low density high strength properties.
The influence of glass beads for drilling fluid lubricity
Glass beads spherical structure, which has high hardness, smooth surface, such as features, rolling performance is good. Use it as drilling fluid additives, can play a role similar to the bearing in the ball, greatly reduce the frictional resistance of drill pipe, drilling fluid, fast bit drilling, improve the rate of penetration, and reduce the bit wear.In the experiment, the Caspian sea region with diameter less than 0.9 mm of glass beads, adding quantity is 5 ~ 20 kg/m3, the results make it required torque drill pipe reduced 30% ~ 60%.
Now, in the exploration and development is difficult, purpose layer under the condition of buried depth, low formation pressure with application of glass beads in underbalance drilling has many advantages, one of the biggest advantages is the glass beads can improve drilling speed; From the shaft to the differential fluid pressure of formation fluid in the range of 0 ~ 6.9 Mpa, the common drilling method in sandstone, limestone, shale drilling efficiency would lower 70 ~ 80%, and the glass beads can reduce wellbore pressure significantly improve drilling efficiency.
Beads of recycling
Proportioning cost, because of the large dosage of hollow glass beads are relatively high, can be recycled to become important factors restricting the popularization and application of the glass beads drilling fluid can, and only when the beads for 50 ~ 100%, the recovery of hollow glass microsphere, the cost of drilling fluid can with the cost of conventional water-base drilling fluid.
Belonged to non-newtonian fluid, drilling fluid for non-newtonian fluid, the sedimentation rate related to the rheology, has nothing to do with the density difference between the medium. Based on this principle: recycling glass beads, especially in the water-base fluid recycling glass beads, water damage fluid rheological property can be used qualitative methods.In essence, is the drilling fluid from the Newton fluid into the Newtonian fluid. A series of data show that recovery rate and final reduced with increase with the increase of the amount of dilution. This method is applicable at the scene, only will be separated from the solids control equipment of the drilling fluid and completion fluid discharge to prepare a good pool, and then add plenty of water, good beads will be floating on the surface of the water.
This article from the guest baba