Preparation Of Petroleum Proppant From Oil-shale-dreg

The hydraulic fracturing technology is one kind of effective technology which contribute to improve oil production. The pressure produced by a group of high-pressure pumps is higher than that of the strata in the oil-well, it can create additional passageways in the reservoir. The macroviscosity-breakdown-fluid containing proppants can make the proppants pass into the passageways, so the paoppants in the fractures offere additional channels which has a certain geometry size and has a high flow conductivity, thus the production of oil well is improved. It is very important to study and improve the charateristic of the proppants in the increasing of the oil well production.It is classified the petroleum fracture proppant into 3 types:natural quartz sand, artificial ceramic proppant, resin coated proppant. And the resin coated proppant can be divided into two kinds:coated sand and coated ceramic sand. The natural quartz sand is generally used in shallow oil well because of its round sphericity is not good and the strength is low, but the cost is lowest. The artificial ceramic proppant usually used in moderate-depth oil well because its round sphericity is good, the strength is high, and it can povide a high flow conductivity and can resistant corrosion. The sand coated by resin can increased its stength and lowe the density, so the coated sand can replace the ceramic proppant to be used in the moderate-depth well. The research of resin coated ceramic proppants was few, and it is expensive, so it has not used in production now.The traditional method to the make ceramic proppant is mainly using the bauxite and flux phase (such as manganese powdered ore) according to the certain proportion, by the smashing attrition (300 mesh of granularity), pelletizing using the disc pelleter according to one-step pelleting method, finally the midium-density or high-density ceramic proppants is calcanating in high temperature.In this paper, it is used the oil-shale-dregs, the bauxite and flux phase according to certain proportionate, through smashing, pelletizing, finally the low-density ceramic proppants being calcanated in high temperature.The oil-shale-dregs is the wastes after refining the oil shale to obtain the shale oil. The oil-shale-dregs not only need taking the massive lands to be piled up,and also include the massive heavy metal element. After passed through by the rain water, it may seriously pollute the water source and the soil, and cause the soil poisoned, acidified, low soil productivity, destruct the agricultural, finally make harms to the human being. But in the oil-shale-dregs, there are the massive mineral component, like the quartz, the feldspar, the clay ingredient and so on. After distillation calcine, its structure becomes loose, owning the very low density and much ignition loss. Using the oil-shale-dregs to prepare the ceramic proppant and the film coating ceramic proppant, not only can reduce massive land occupancy, eliminate the burden of the environment, the ecology, and the human being's health,but also may enhance the value of oil-shale-dregs. Therefore it is of great importance to make the oil-shale-dregs change to resources.Theoretically, the traditional ceramic proppant is a pure corundum phase as the support skeleton, the glass material as cohesive part, that make the entire ceramic proppant to have the very good stength and high anti-corrosive ability. Based on this theroy, by adding the oil shale residue, it can increase the mullite content content in the ceramic proppant. It makes the proppant with high strength and lower broken percentage on high pressure by interweaves toughness produced by the mullite phase. In addition, when two raw materials mix uniform, organic matter and iron oxide contained in the oil-shale-dregs can oxidize the carbon components faster, and easily form uniform closed pores, so the bulk of ceramic density and apparent density become smallerUsing of the above advantages of the oil-shale-dregs, it is prepared the low-density oil proppant and the coated proppant, the innovations include:(1) It is for the first time prepared the low density oil ceramic proppant that is satisfied the national standards by adding 30%wt solid waste-oil-shale-dregs residue to the bauxite.(2) It is for the first time prepared the coated oil proppant which is satisfied the national standards and with pro-oil hydrophobic properties and by adding 50%wt of the oil-shale-dregs to the bauxite. The proppants have the high strength and the high flow conductivity.(3) It is for the first time usingρ-Al2O3 as the cementing agent in the ceramic proppant, which obviously enhanced the performance of the proppant.In this paper, firstly it is burnt and milled the oil shale which is from the Mudanjiang City, Heilongjiang Province, then analyzed its loss on ignition, density, mineral components and micro area morphology. And on this basis, it is prepared the low density ceramic proppant through the granulation, high-temperature sintering by the use of the mixture according to a certain percentage of oil-shale-dreg powder and bauxite powder, with a certain quantity of flux-phase (such as manganese powder). Following this, it is systematically studied the influnce of the icosahedral,the bulk density, apparent density, the broken percentage, conductivity, corrosion resistance, mineral phases and the micro-area morphology of the proppant by adding amount of oil-shale-dreges and the flux, the sintering temperature and sintering time. In connection wth the problems of the every kind of ceramic's performance, it is studied the sintering flux by the use of iron oxide powder instead of manganese powder, the reducing of the harmful ingredients, such as calcium oxide, by acid treatment; the selection of variety of binders. Through all of the experiments, it is analyzed the influnce of the percentage the chemical composition of the ceramic materials, the impact of the composition on the ceramic, the principle of granulation, and the principle of the sintering and the growing up process of the ceramic crystals. Finally, it is prepared coated ceramic proppant with high performance, low-density by using of the aggregate which is prepared by adding 50%wt of the oil-shale-dreges, coating by coupling agent, curing agents and epoxy resin mixed with phenolic resin and the plasticizer.The paper obtains the following main conclusions:1. It is for the first time prepared the oil proppant using the oil-shale-dregs, the raw materials being:10-30%wt of oil-shale-dregs,70-90%wt of the bauxite, adding 2%-6%wt of manganese powder, 1-3.5%wt of cementing agent. The ceramic proppant prepared is satisfied the national standards. The prescription of this paper is the wholly self-owned intellectual property rights. The anather advantage of the oil proppant is its low density:1.52g/cm3 of the bulk density,2.90g/cm of the apparent density,7.56% of the broken percentage under 52MPa, it obviously surpasses the traditional ceramic proppant(1.7g/cm3 of the bulk density, large than 3.15 g/cm3 of apparent density).2. As a high temperature cementing agent, the advantage of theρ-Al2O3 is that it may hydrolisis in the low temperature, produce three diaspores and boehmite gel, and increase the bonding strength of the ceramic crude material ball. Its activity is very high under high temperature, it may unify with the corundum, also produce the mullite, connect the crystal. It is for the first time to useρ-Al2O3 as the cementing agent in the production of the oil proppant.3. It is for the first time prepared a coated proppant by using the resin mixed with phenolics and epoxy resin (proportion being 2:1), which has low density, high strength, and with the hydrophobic and lipophilic properties. Its bulk density is 1.38g/cm3, the apparent density is 2.35g/cm3, the percentage of broken is 2.16% under 52MPa, and the acid solubility 1.05%, which is satisfied the national standards request. Compared with the ceramic proppant, the strength of the resin coated proppant increases greatly, its percentage of broken may reduce 10%-20%, and the bulk density and apparent density is also very low, the acid solubility is reduced about 5%. Before coated, it only needs 9s when water Infiltrated,80s when the salad oil, but after coated, the penetration rate reduces obviously, it needs 90s to the water 120s to the salad oil, the time need to the water grew 10 times, but to the oil grew about 1.5 times.4. It is determined the best conditions for the oil proppant and the largest influncing fator by orthogonal experimental method. The best experimental conditions is A3D2B2C1, that is, in 100g of the oil proppant, adding 6g mixture of resin and epoxy resin by the ratio of 2:1,0.5ml of phthalate plasticizers,0.1ml of coupling agent VTES,0.4ml of curing agent triethylenetetramine and 0.25g of lubricants polyester, and the reaction temperature being 190℃, total reaction time being 1h. It is concluded from mean square deviation that the main factors is the resin, the secondary factor is the amount of additing of curing agent, plasticizer and coupling agent.5. Compared with manganese powder, the iron oxide powder as flux phase is bad, but it could promote the mullite production. When adding iron oxide to 7%wt, the bulk density is 1.58g/cm3, the apparent density is 2.93g/cm3, the broken percentage is 11.89%. Analyzed by the X-ray diffraction, by adding oxidizes iron powder, the content of mullite is higher than that of the corundum, which is revealed that the iron oxide could promote the mullite production.6.The best percentage of flux phase is 5%wt of MnO2, Fe2O3; FeO, TiO2 and 1～3%wt of Na2O, K2O, CaO, MgO.7. The calcium oxide content in oil-shale-dreges is reduced by using the acid pickling, that also reduced the content of the feldspar in ceramic proppant. The best bulk concentration of the acid is 20%. After the acid pickling experiment, when not adding cementing agent, the ceramic proppant prepared is not very good, it needs further study.