44results about How to "Increase net pressure" patented technology

The invention relates to a shale gas fracturing stepping sand-adding method which comprises the following steps: (1) pumping a prepared fluid into a shaft and causing the fluid enter into ground gaps; (2) pumping a first sand-adding section plug and performing the stepping sand adding; (3) pumping a first fluid section plug, and if the pressure shows as diagonal rising, confirming that the pressure change is mild and the sand ratio has a rising potential, and then skipping to the step (4), and if the pressure shows as the sand ratio rising unsuitable for the present stage, further pumping the fracturing fluid for forming gaps and then skipping to the step (1); (4) pumping a second sand-adding section plug and performing the stepping sand adding; (5) pumping a second fluid section plug and observing the pressure variation trend of the sand-adding section plug at different sand ratios after entering into the stratum; and (6) repeating the steps (4)-(5) for 15-20 times till meeting the requirement for designed fracturing sand-adding volume, completing the sand adding in each stage, and lastly, pumping the displacing liquid and completing the whole fracturing construction task. According to the invention, the stepping sand-adding method is adopted for effectively preventing reservoir sand blocking, reducing the construction risk and guaranteeing the smooth construction.

The present invention relates to a multifunctional drag-reducing water system for continental shale gas fracturing and a preparation method thereof. The components and mass percentages of the multifunctional drag-reducing water system for continental shale gas fracturing are as follows: Drag reducer 0.02-0.05%, inhibitor 0.5-1%, anti-scaling agent 0.1-0.3%, synergist 0.001-0.003%, regulator 0.2-0.5%, and the balance is water. The multi-functional drag-reducing water system provided by the present invention has the characteristics of high drag-reducing rate, strong suppression, reduced imbibition, and reduced adsorption. , chemical reaction, promote the rapid flowback of fracturing fluid, reduce the adsorption damage of fracturing fluid, meet the requirements of continental shale gas fracturing construction, reduce the damage of drag-reducing water fracturing fluid to reservoirs, and realize continental shale Efficient development of gas.

The invention belongs to the field of oil exploitation and particularly provides an oil-gas reservoir fracturing construction method. The oil-gas reservoir fracturing construction method comprises a prepad fluid stage and a main sand adding stage. According to the prepad fluid stage, fracturing liquid is injected at multiple levels of construction displacement which is increased level by level from the lowest construction displacement to the highest construction displacement; and according to the main sand adding stage, sand-carried liquid is injected at the highest construction displacement,wherein the lowest construction displacement is 45-65 % of the highest construction displacement. In the preferably-selected implementation mode, design is conducted according to different construction sections, the different fracturing liquid displacement and corresponding fracturing liquid viscosities and using quantities are adopted, the mode of different-particle-diameter variable density sandadding is adopted, by utilizing the setting effect of a supporting agent, the net pressure in cracks at the supporting agent non-setting position is increased, thus the seam making height and the supporting height of remote well cracks are increased, the flow guiding capacity of the cracks at remote wells is improved, and the progressively-decreasing speed of the single-well capacity is decreased.

The invention discloses a fracturing technique for achieving a complex crack through multiple particle class differential temporary blocking, which is fracturing technique that a primary artificial crack is temporarily blocked through rigid temporary plugging agent composition with particle size class differential carried by a fracturing fluid, net pressure in the crack is improved, and a new sidecrack is opened. The fracturing technique comprises the steps that the rigid temporary blocking agent carried by a biodegradable polylactic acid resin-like fiber fracturing fluid with four kinds of particle size class differential combination is fast injected according to the sand mulling concentration of 350-500-650g / cm3, and crack deep part temporary blocking is carried out; the net pressure inthe crack is improved, and the side natural crack is opened, and side remaining oil is effective used; and the oil well single well production and final recovery ratio are improved. The fracturing technique has the advantages that the operability of the construction technique is high, a complex fracture system is fractured to be formed, the using degree of the oil well side remaining oil is improved, the cost is low, and the oilfield development benefit is greatly improved, and solves the difficult problem of the poor repeated fracturing effect of low-permeability reservoirs.

The present invention provides a high-efficiency self-generated gas foam fracturing fluid and a construction method. The foam fracturing fluid is composed of a base fluid, a gas-generating fluid and a heat-generating agent, wherein the mass ratio of the base fluid, gas-generating fluid, and heat-generating agent is 100: (30‑42): (5‑9). During construction, the base fluid and the gas-producing fluid are pumped downhole together through the suction of the sand mixing truck according to the mass ratio, and the heat generating agent is pumped into the downhole along with the proppant. The invention does not need liquid nitrogen accompanying injection, simplifies the on-site process and reduces the construction cost, and a large amount of gas generated through the chemical reaction achieves the purpose of increasing the energy of the formation, improving the flow capacity of the reservoir liquid, and increasing the output. It can quickly generate a large amount of inert and safe gas, and will not produce toxic gas of nitrogen oxides, reducing construction risks. At the same time, the alkaline environment generated by the reaction product is conducive to the formation of fracturing fluid gel and the corrosion protection of downhole pipe strings. By generating foam, the Jiamin effect is used to increase the net pressure of the formation, which can quickly flow back, generate heat in the deep formation to promote gel breaking, and reduce the damage of fracturing fluid to the reservoir.

The invention discloses a volume fracturing method for activating natural fractures in a large range. Including: step (1) parameter evaluation and optimization; step (2) joint perforation operation under bridge plug; step (3) acid pretreatment operation; step (4) joint construction in low-viscosity slick water or acid slick water; (5) Construction of mixing proppant and sand to plug main cracks; step (6) construction of step-up displacement; step (7) mixed injection construction of 140-210 mesh proppant and 70-140 mesh proppant; step (8) high-viscosity construction The fracturing fluid does not add sand to flush the main fracture construction; step (9) the second and third main fracture plugging and subsequent construction; repeat steps 5) to 8); then, repeat steps 5) to 7); step ( 10) Adding sand to the main fracture with high-viscosity fracturing fluid; step (11) replacement operation. The invention can increase the complexity of fractures and the volume of stimulation during reservoir stimulation, thereby realizing high-efficiency production increase of shale gas wells.