Southwest Petroleum University

Youshi Jiang

Yongming Li

Jinzhou Zhao

Xiyu Chen

Bo Chen

Qiang Ren

Juhui Zhu

Yan Kou

Dingli Wang

Wenjun Xu

Yu Peng

Liehui Zhang

Ang Luo

Yitao Huang

Dongyu Fu

Lirui Zhong

Jingkai Hu

Huibo Wen

Zhibin He

Jing Jia

Wang Tang

Fujian Liu

The present invention discloses a method for realizing uniform stimulation for the oil and gas well by low-cost multi-stage fracturing, comprising the following steps: first calculate and predict the inlet widths of the fracture created in the planned hydraulic fracturing; then design the plugging scheme for blocking the fracture inlet after each fracturing treatment; the selected plugging particles are composed of filling particles and skeleton particles, with designed plugging scheme; after complete the design of plugging scheme, perform the fracturing treatment to create hydraulic fracturing in the reservoir; skeleton particles and filling particles are added into the fractures successively according to plan. The present invention provides a multi-stage single-cluster fracturing method, with the advantages of controllable fracture sizes and low cost. The present invention can realize a good uniformity of stimulation for the oil and gas wells.

Method for realizing uniform stimulation for the oil and gas well by low-cost multi-stage fracturing

The present invention discloses a method for evaluating fracture connectivity and optimizing fracture parameters based on complex network theory, comprising the following steps: obtaining natural fracture distribution laws and characteristic parameters of the formation based on previous knowledge of natural fractures in the formation and statistical analysis of fractures in the core, and establishing a discrete fracture network model of natural fractures based on the previous step; setting up hydraulic fractures, determining intersection relations in the fracture network and coordinates of intersection points of fractures: converting the actual fracture network into a complex network dual topology diagram based on complex network theory, and calculating evaluative indexes of the complex network to realize the evaluation of fracture network connectivity; changing the hydraulic fracture parameters to get the evaluation indexes of different hydraulic fracture schemes.

Method for evaluating fracture connectivity and optimizing fracture parameters based on complex network theory

A quadripolymer based on host-guest interaction and prepared in the steps including (1) weigh maleic anhydride and dissolve in dichloromethane, add &#x3b2;-phenethylamine dropwise, stir to react for 1 to 3 hours, perform extraction filtration and washing, to obtain N-phenethylmaleamic acid; (2) weigh mono 6-ethylenediamine &#x3b2;-cyclodextrin and maleic anhydride, dissolve in N, N-dimethylformamide, and place at 40&#xb0; C. for reaction for 3 to 6 hours, the product is precipitated with chloroform, washed and dried under vacuum to obtain maleic anhydride modified mono 6-ethylenediamine &#x3b2;-cyclodextrin; (3) Add acrylamide, acrylic acid, maleic anhydride modified mono 6-ethylenediamine &#x3b2;-cyclodextrin, N-phenethylmaleamic acid, adjust the pH of the solution to 7; introduce nitrogen, add a photoinitiator and place to a photo-initiating device to react 3&#x2dc;5 hours at a temperature of 10&#x2dc;30&#xb0; C. The quadripolymer has good temperature and salt resistance, shear resistance. The raw materials are cheap and easily available. The reaction conditions are mild.

Quadripolymer based on host-guest interaction and preparation process thereof

The present invention discloses a process for preparing a Mannich base quaternary ammonium salt high-temperature resistant corrosion inhibitor and applications thereof. The preparation process comprises the following steps: (1) dissolve an amine substance indole, benzhydrylpiperidine, diphenylethylamine, dibenzylamine or diisopropanolamine into an organic solvent, slowly add an aldehyde substance 3-(2-thienyl)benzaldehyde or cinnamaldehyde, then place in a constant-temperature water bath, stir to react at 60-80&#xb0; C. for 1 to 3 hours, then add a ketone substance benzalacetone, diphenylstyryl acetone or 1,1-diphenylacetone, adjust the reaction system pH to 3 to 4 using a hydrochloric acid solution, and then react for 7 to 10 hours; after cooled to room temperature, perform distillation under a reduced pressure to remove the solvent, to obtain a Mannich base; (2) dissolve the Mannich base in an organic solvent, add quaternizing reagent chloromethylnaphthalene, benzyl chloride or triphenylchloromethane, then react at 70-90&#xb0; C. for 14-16 h, after cooled to room temperature, perform distillation under a reduced pressure. The process is simple and feasible, and its raw material is non-toxic, safe and environmental-friendly, and the prepared corrosion inhibitor has obvious resistance to the acid corrosion of carbon steels in oil-gas wells.

Process for preparing Mannich base quaternary ammonium salt high-temperature resistant corrosion inhibitor and applications thereof

The present invention relates to a channel fracturing method with alternative injection of conventional and capsule-type soluble proppants. The method includes the following steps: injecting pad fluid into a wellbore to break a formation and form fractures in the formation; alternately injecting a sand-carrying fluid containing conventional proppant and a sand-carrying fluid containing capsule-type soluble proppant into the wellbore in sequence to support fractures in the formation and continue to fracture the formation; injecting displacement fluid into the wellbore to completely displace the sand-carrying fluids in the wellbore into the fractures. The conventional proppant of less dosage is used. The capsule-type soluble proppant is less difficult to be developed and its solubility is sensitive to the fracture closure, which is conducive to the quick flowback after fracturing. The channel fracturing technology is more mature, reliable, and cost-effective, and the concept of forming high-conductivity channel is more simple and effective.

Channel fracturing method with alternative injection of conventional and capsule-type soluble proppants

A testing device and method for floating rate of floating agent for fracture height control are provided. The test device includes a support frame, a glass tube vertically fixed on the support frame, a floating agent storage container, a control valve, and a liquid storage tank, wherein multiple circular holes are uniformly distributed along an axial direction of the glass tube, and multiple turbidimeters for measuring liquid turbidity are sequentially mounted on the circular holes. The liquid storage tank communicates with an inner cavity of an upper end of the glass tube through a pipeline, and the floating agent storage container is connected to an inner cavity of a lower end of the glass tube through a control valve. The present invention increases accuracy of measured floating rate of the floating agent, and provides reliable floating data of the floating agent for oil and gas reservoir reconstruction.

Testing device and method for floating rate of floating agent for fracture height control

The present invention discloses a process for preparing a dibenzylaminquaternary ammonium salt high-temperature resistant corrosion inhibitor and applications thereof. The preparation process comprises the following steps: (1) Dissolve the amine reagents benzylamine, phenethylamine, morpholine or indole in an organic solvent, slowly add epichlorohydrin dropwise, stir to react at a room temperature for 12-14 hours, and then distill under reduced pressure, and wash to obtain an intermediate I; (2) Dissolve the intermediate I in an organic solvent, add dibenzylamine at a ratio, then add an acid binding agent, warm to 60-80&#xb0; C. to react for 14 to 16 hours, after cooling to room temperature, perform filtration, extraction and distillation under a reduced pressure to obtain an intermediate II; (3) Dissolve the intermediate II in an organic solvent, add quaternizing reagent at a ratio, then warm to 80-110&#xb0; C. to react for 12 to 15 hours, after cooling to room temperature, perform filtration, extraction and distillation under a reduced pressure to obtain the dibenzylaminquaternary ammonium salt high-temperature resistant corrosion inhibitor. The process is simple and feasible, and its principle is reliable, and the prepared corrosion inhibitor has good resistance to the acid corrosion of carbon steels in oil-gas wells.

Process for preparing dibenzylamine quaternary ammonium salt high-temperature resistant corrosion inhibitor and applications thereof

A method for optimizing perforation parameters to maintain uniform fracture growth in multi-stage hydraulic fracturing of horizontal well and device therefor are provided. The method includes steps of: S: collecting the geological and engineering parameters of the targeted pay zone, and estimating the net inlet pressure of fractures within the targeted fracturing stage of horizontal well; S: calculating the perforation friction coefficient required for maintaining the uniform fracture growth in multi-stage hydraulic fracturing of horizontal well; S: calculating the perforation characteristic parameter; and S: determining the optimized perforation parameters. The method considers the stress heterogeneity, the stress shadowing and the perforation erosion in the process of dynamic hydraulic fracturing propagation, and also the influence of perforation erosion. The invention can effectively maintain uniform fracture growth in multi-stage hydraulic fracturing of horizontal well, which can easily operate and is practical.

Method for optimizing perforation parameters to maintain uniform fracture growth in multi-stage hydraulic fracturing of horizontal well

The invention provides a method for predicting a reservoir reform volume after vertical well volume fracturing of a low-permeability oil/gas reservoir. The method sequentially includes the following steps: (1) calculating an induced stress produced by a hydraulic fracture in a three-dimensional space; (2) calculating a stratum pore pressure obtained after leak-off of fracturing fluid; (3) calculating a stratum pore elastic stress obtained after the leak-off of the fracturing fluid; (4) overlapping the stress fields obtained in the step (1), (2) and (3) with an original crustal stress field to obtain a new crustal stress field, and calculating the magnitude and direction of the overlapped three-direction effective principal stress in the reservoir space; (5) calculating an open fracturing determination coefficient M of a natural fracture in the reservoir space and a shear fracturing area determination coefficient S of the natural fracture.

Method for predicting reservoir reform volume after vertical well volume fracturing of low-permeability oil/gas reservoir

The present invention discloses a sulfonate lycine type hydrophobic associated polymer and a preparation method thereof. A preparation process of the sulfonate lycine type hydrophobic associated polymer comprises the following steps: firstly, mixing acrylamide and acrylic acid in an aqueous solution; adjusting pH of the system to be around 6 to 8; adding 3-(dimethylamino propyl methacrylamide) propanesulfonate, N-aryl-N-alkyl (methyl) acrylamide and lauryl sodium sulfate and stirring till the solution is clear; and after nitrogen is introduced for deoxidization, adding a photoinitiator azobis (isobutylamidine hydrochloride) for performing polymerization under photoinitiation conditions. The sulfonate lycine type hydrophobic associated polymer integrates the advantages of a two-tailed hydrophobic associated polymer and the advantages of a lycine type polymer, such that the viscosifying property, the temperature resistance, the salt resistance and the hydrolysis resistance of the sulfonate lycine type hydrophobic associated polymer are remarkably improved.

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Chengdu, China

Youshi Jiang