Clean fracturing fluid and proppant transport laid an important impact on the fracturing effect

Clean fracturing fluid and proppant transport laid an important impact on the fracturing effect, currently based in this area are more theoretical research and field test, and experimental research on indoor less.A transparent parallel plate fracture filling simulation device for four factors proppant settling laws were studied. The results showed that: the greater the viscosity,the sedimentation rate is smaller; fracturing fluid sand-carrying performance with increasing displacement, reduce proppant density linear growth law; the sand was less affected than the sedimentation rate; which three main factors the impact of fracturing fluid carrying capacity of descending order of clean fracturing fluid viscosity,density and proppant sand-liquid ratio.Recognize proppant settling rules can be further improved rationality fractured wells construction
parameters.
Proppant in the fracture sanding concentration,distribution, etc.are laid way affect the important fracture conductivity.The factors that determine the distribution of proppant in the fracture displacement law including collision construction,operation pressure,sand-liquid ratio, fracture surface, proppant particles between proppant and fracturing fluid properties and so on.It has been reported in the Fracturing proppants settling in the law, but has not yet formed a systematic research. Therefore, strengthening the settlement of the proppant in the fracture, and has important practical implications for oil fracturing wells.
Domestic researchers discussed migration and law laid proppant in theory, field test mainly rely on simulation software, there are few aspects of research experiments. Transparent parallel plate device research proppant law laid artificial fracture to guide mine construction.

Fracture mining technology

Fracturing technology by injecting sand, water and chemicals into wells, the formation of cracks in the shale formation and extraction of natural gas. Due to the level of drilling technique, the changes in mining techniques for the development of non productive deep shale formations over the past ten years, conventional,unconventional natural gas and two other forms of (tight gas, CBM) along with the increase of 30%-40% of domestic energy production.

But some people think that the energy gain is costly, and France, the United States of New Jersey and New York, due to the environmental impact of worry, has banned takefracturing technology of hydraulic mining.

In the numerous of mining process view, there is a thought that this will pollute thegroundwater, caused by the earthquake, causing chemicals such as methane andbenzene leak into the air. So far, oil and gas regulators and other groundwater protection experts also found no sign that is directly linked to the China proppant and groundwater pollution, but also did not conduct a comprehensive research on this technology.

Civil and Environmental Engineering Department of University of Texas-Austinprofessor Danny Reible recently by virtue of its groundwater expertise in helping the U. S. environmental protection agency to study the Fracturing proppants , he thought that the occurrence of pollution may be due to poor drilling design and construction or waste management surface bad.

Technical construction of oil proppant production safety and quality requirements

Petroleum proppant for clothes, skin corrosion strong, with liquid, must pay attention to safety during construction.
(1) pay attention to the preparation of oil proppant Wear PPE, bold but cautious, there is someone in charge of directing with liquid and well in advance of each lotion, once splashed acid in the body, the face you want to rinse with water, heavy timely sent to hospital for treatment.
(2) with a good oil proppant placed after the ferry to check the acid tanker valves, liquid inlet lid is on tight, can not have drip, drain phenomenon. Vehicle shall be marked with the danger mark at the wellsite shipped cracks pay attention to safety.
(3) the construction team on well after construction should be carefully checked before the wellhead valves are complete, whether the screws tightened to the construction until after passing the wellhead. Firstly wellhead natural gas fracking test the pipeline construction, leak-free mayonnaise, the only sour note to the well.
(4) When a large amount of acid, when a new well acidizing process to prepare the production command vehicle, ambulance wells.
(5) in strict accordance with the design and construction. The quality of acidizing is directly related to the post-acid effect. Therefore, we must ensure construction quality.
① conduct tests, before acidizing, a clear division of labor, unified command: Non-staff shall enter the high-fracking process zone.
② strict accordance with design requirements, acidizing.
③ guarantee the construction of the oil leak proppant not AIDS, given the amount of fluid play enough design.
④ for matrix acidizing pump pressure must not exceed the fracture pressure, ready to observe the construction of pump pressure, ranked the most changes.
⑤ take full, take prospective construction pressure, displacement, construction time, etc., well carefully recorded.
Late Management (four) Construction
After acidizing oil and gas wells, bad management, construction related to the effect of acidification. After acidizing wells shut as designed after timely open wells. If self-spray nozzle is installed drainage capacity requirements; generally when dropped O.1% residual acid concentrations, flowing well stop production of crude oil, non-flowing well from a string acidified turn pump pumping into production. Not since the spray is necessary and timely rehearsal is the key to prevent secondary precipitation acidification success. Oil and gas wells in the production process should be carefully recorded oil, casing fracturing fluid , daily production of oil and gas and other data, such as the timing of the measured fluid level wells. With drainage conditions on injection wells after acidizing according to design requirements to drain residual acid, restore water when the residual acid dropped when OI%; do not have drainage conditions, timely recovery water injection wells, the residual acid formation squeeze Deep. Carefully recorded during the injection pump fracturing proppant , casing pressure, oil fracturing sand , water injection daily, injected water quality data, timing measurements indicate absorption curve, the injection profile and so on.After acidification with a note for a smooth construction by water injection rate can not be too large, otherwise easily lead to the formation velocity sensitivity, acidification effect: To inject water quality water quality standard character sets, this plug formation injection wells, acidified to fail.

Production of ceramic proppant should note the following seven elements

In this paper, the main raw material level bauxite, dolomite, boric acid, bentonite, precipitated barium sulfate as a secondary raw material to manufacture Ceramic proppants, investigated the effect of addition of various raw materials for proppant performance. The results show that the ratio of raw materials through the rational design of improved granulation process and select the appropriate firing temperature can develop excellent performance ceramic proppant. After industrial production practice, confirmed that the design of the production process is feasible. Study the following conclusions:
(1) According to the Al203-Si02 binary phase diagram, select the level of bauxite-based raw material, adding a certain amount of auxiliary materials can produce excellent performance of ceramic proppant, the process parameters are affordable range of company equipment within;
(2) silica powder because small particles can be effectively filled in the gaps between the bauxite and other fines, in the firing process, due to their activity, is conducive to reduce the sintering temperature, while an appropriate amount of silicon powder also help to improve performance;
(3) is introduced in the form of barium sulfate, barium oxide, barium carbonate and the effect of the introduction of barium oxide can be increased as the strength of the proppant. When the amount of barium sulfate 超过 5 lnj weak s%, the intensity decreases sharply, so the amount should not exceed 5 m weak s%;
(4) Add 2 mass% of dolomite, can effectively reduce the acid solubility, but also can reduce the sintering temperature, play to save energy, reduce the cost of action. Bentonite is introduced to increase the strength of semi-finished products, reducing the ash off phenomenon during storage and transportation process, you can drop ring formation is only the chance to improve the pass rate;
(5) By comparing the various methods on Oil fracturing proppant granulation performance, designed a new granulation process. First, the new technology is the traditional spray drying equipment to do the following improvements:
I) will be expanded to the hole diameter piece 2.5-2,8 mm:
II) The non-porous flat plate to 2.8-3.0 mm perforated cover:
The improved slurry discharged after reducing the shear rate to give a smaller spray angle and increase the droplet diameter, to obtain a better particle. By controlling the water content in the slurry, while optimizing the spray drying parameters, can greatly improve the appearance and quality of the particles, not only a uniform particle size, but also eliminates the center due to the rapid evaporation of water vapor generated enormous pressure to form a fracture surface of the particles cavity; good sphericity particles, greater density (1.2-1.3g, cI113). But still relatively rough surface of the particles, but also close enough, on this basis, select the sugar coating machine treatment processes and achieved good results;
(6) the density and particle size of the raw material have a certain impact on the performance of the proppant, especially some larger particle size effects. Raw material particle size of 0.004 mm obtained proppant strength higher than the particle size of 0,01 mm of 80--90%, the particle the higher the density the greater the strength;
(7) the firing control Proppants for hydraulic fracturing an important part of the final performance, in order to prevent burning and burnt due to the occurrence, the firing temperature must be strictly controlled. In this study, the ratio of the material, the optimum firing temperature of 1360 ± 5 ℃, so that one can guarantee the quality of products, on the other hand can greatly improve the pass rate.

Petroleum proppant

Called oil fracturing proppant , along with a high-pressure solution proppant into the formation maide oil fracturing proppant filling in cracks in the rock , play a supporting fissures not because of stress release and closed , thereby maintaining high conductivity , so that the oil and gas flow, increase production. Also known as petroleum oil proppant fracturing proppant . After deep mining in the oil and gas , high pressure low permeability deposit after closing fracturing treatment, the rock cracked petroleum , oil and gas from the cracks in the channel formed by the collection of out of the fluid injected into the rock at this grassroots needs to exceed formation fracture compressive strength , making the rock around the wellbore cracks , forming a high-level flow channel has the ability , in order to maide fracturing proppants maintain after fracturing the formation of cracks in the open , the oil and gas product can smoothly pass. Along with a high-pressure solution proppant into the formation filling in cracks in the rock , not because of stress fractures play a supporting release of closed , thereby maintaining high conductivity , so that the oil and gas flow, increase production.