Currently there are mainly three types of fracturing proppants in the market, natural sand, resin coated sand and ceramic proppant.
Properties of Different Proppants
Natural sand is the first kind of fracturing proppant used in hydraulic fracturing process with lower cost. According to the API or ISO standard, it’s only applied to the shallow wells of which the closure pressure is from 4,000 to10,000psi. Natural sand is easily crushed during carriage and damages the pump because of the low roundness and sphericity. The quality of the sand differs a lot because of the different sand mine locations in different countries.
Resin coated sand is coated on the surface of natural sand to enhance the compressive strength. However, at the certain temperature and pressure, the resin will be sticky and the sand inside will be crushed, these will plug the fracking cracks which will reduce the long term conductivity and the output of the wells.
The main raw material of ceramic proppant is bauxite, which is sintered with high temperature, thus the sphericity and roundness is better. At the same time, the compression strength can reach 30,000psi and it has high conductivity, which can significantly improve the oil & gas production.
From the HSE side, the silica of natural sand has negative impact on the environment. The pollution during resin coated sand production process and fracturing process is also obvious. In contrast, the main raw material of ceramic proppant is bauxite which is from nature and used to the nature (injected to the layer to keep the ground rock from collapsing by filling into the cracks). After sintering, the ceramic proppant has higher strength and will be more stable to support the cracks.
For a customer, how to choose the right proppant depends on the output and long term benefits. It’s obviously that the proppant with long term conductivity and using life will be the first choice.
There are some factors that would affect the proppant conductivity, particle size, sieving distribution, strength (crushing rate), shape (sphericity, surface smoothness), etc.
As a professional ceramic proppant supplier, Wanli focuses on the production, research and development and sales of ceramic proppant more than twenty years. Wanli does some research on the difference among different proppants. Details as below:
1. Sphericity, roundness and surface smoothness
Ceramic proppant has better sphericity, roundness and smoother surface, which can reduce the wear of fracturing equipment when pumping. But the shape of natural sand will be changed a lot while the pressure increases, the wear of fracturing equipment is four times higher than that of ceramic proppant, which will reduce the long term conductivity rapidly.
2. Strength (crushing rate)
From figure 1 we can see that the crushing rate of natural sand and resin coated sand increases rapidly at the certain pressure. Bad stability could lead the cracks to collapse.
3. Sieving distribution
During the process of ceramic proppant sintering, the sieve distribution can be controlled strictly and the particle size distribution is more concentrated which can increase the conductivity.
From the conductivity data of different proppant with the same size, as shown in Figure 2, we can see that the conductivity of the ceramic proppant is much better than the natural sand and resin coated sand. Thus, the oil & gas production will be much better when using ceramic proppant. Therefore, ceramic proppant is the most ideal fracturing proppant with the lowest cost based on its’ long-term cost and benefits. (See Figure 3). But under this badly market circumstance, the operators have to choose the lowest price natural sand to fracture to cut cost. But we believe that the operators will make different choice when the oil industry warms up or the price and performance of the proppant have new breakthrough.
Case Study: Natural Sand VS Ceramic Proppant
Cost, cost and cost
Since the second half year of 2014 till now, the oil price has fallen from 120$/barrel to 28$/barrel, now the oil & gas price is the motivation for exploring, when the purchaser purchases proppants and other equipment for fracturing, they will consider the cost issue, all the oil & gas companies have to struggle to survive under the current depressing market.
As a manufacturer of ceramic proppant, we notice that many fracturing activities switched ceramic proppant to resin coated sand and/or natural sand, the ceramic proppant industry is facing terrible crisis they have never met before, but we know that every coin has two sides, where there is crisis there is opportunity. How to survive and break through is the real matter now.
Wanli substitution ceramic proppant: (can substitute natural sand)
Wanli pays close attention to the current clients’ demand and proppant market, after thousands of experiments with different raw materials, we successfully developed a new kind of ceramic proppant which can substitute the natural sand from the cost issue, and its’ function is much better than the natural sand.
We believe this new product is extremely attractive for the operators, same price for the substitution ceramic proppant and natural sand, which one they will choose for fracturing? Substitution ceramic proppant will be their rational choice.
Wanli discussed with lots of clients and believed that the trend of development of ceramic proppant in the future - super high strength ceramic proppant and functional ceramic proppant.
Super high strength ceramic proppant
For the deep ocean fracturing in the future, super high strength ceramic proppant will be widely used. And it will have strict requirements on the roundness, sphericity and surface smoothness, etc. Compared with the ceramic proppant of 15,000psi, Wanli improves the dosing of ceramic proppant, by adopting different raw materials such as bauxite with higher Al2O3 contend and Kaolin. At the same time, Wanli controls the proppant strength by adjusting the sintering temperature and time during the production process, which can make the strength achieve to 30,000psi, and ensures a higher long term conductivity. Certainly the price of the super high strength ceramic proppant is higher than conventional ceramic proppant.
Functional ceramic proppant
Self-suspension ceramic proppant
The self-suspension ceramic proppant is coated on the normal ceramic proppant by using special polymer which is environmental and can be degraded. After absorbing water, the specific gravity will decrease and meanwhile the water composition will be changed, thus it can suspend in the fracturing fluid. When suspend homogeneously in the fluid, the self-suspension ceramic proppants have better mobility in the formation, which won’t lead to partial accumulation and sand blocking phenomenon. Meanwhile, the self-suspension ceramic proppant is easily operated, and it can save the fracturing time and cut cost. Based on the significant research development of self-suspension ceramic proppant and after some small modification, Wanli will put it into production immediately.
Adsorption ceramic proppant
Wanli has developed another new product - adsorption ceramic proppant, the internal pores occupy 20% - 25% of the whole volume, it has a lower bulk density and the ability of absorbing chemicals can reach up to 15% or so, it can be used in the wells where the closure pressure is no more than 7500psi.
After adsorbing chemicals, the adsorption ceramic proppant will be dried and then mixed with convention ceramic proppant at a certain proportion, these proppants will be pumped into wells finally. The chemicals can be released gradually during the fracturing process which can prevent the oil well plugging, prolong the service life of the oil wells, and reduce the operation cost of chemical re-injection. The adsorption ceramic proppant has different size and shape, Wanli has got small quantity final product through successful pilot production.
All along, the customers expect there will be a kind of proppant whose density is close to water(1.0 g/cm³), which will reduce the usage of fracturing fluid with lower cost and less damage to environment. Although there is no obvious breakthrough till now, Wanli is still working on it.
Though it’s a long way to develop any new product, we will stick on working hard and won’t give up. We believe that Wanli can bring new proppant categories to the global fracturing market very soon and provide more proppant options for customers. Wanli has a faith that we have the honorable mission to grow up with the world oil & gas industry.