China University of Petroleum

Shandong University

Jian Hou

Yongge Liu

Kang Zhou

Qingjun Du

Bei Wei

Yajie Bai

Yunkai Ji

Nu Lu

Ermeng Zhao

Yueliang Liu

Yongsheng Liu

Wenbin Wang

Bo Yu

Dejun Wu

Jiahe Sun

Yu Xue

Xuwen Qin

Ningyu Zheng

Wenbin Liu

Huiyu Wang

Dong Zhao

Zhibin An

Disclosed is a method for determining the dynamic adsorption retention of polymer capsules, belonging to the technical field of oil and gas field development engineering, which includes: (1) carrying out a thermal aging experiment to establish relational expressions between a capsule concentration and an aging time, as well as a polymer release concentration and the aging time; (2) setting up a polymer capsule displacement experimental device to determine the release concentration of polymers in effluent; (3) releasing polymers encapsulated by capsules in the effluent to acquire a total adsorption retention of polymers in a porous medium; and (4) inverting respective adsorption retentions of the capsule particles and the polymers in the porous medium.

Method for determining dynamic adsorption retention of polymer capsules

A method for realizing balanced displacement of crude oil by injection and production optimization coordinated chemical flooding which comprises the following steps: determining the median size and elastic modulus of viscoelastic particles according to the average permeability of the reservoir; optimizing the concentration ratio of the total concentration of the chemical agent; the physical parameters of each layer are counted, and the hierarchical system is combined according to the entropy weight algorithm and the cluster analysis method based on the gravity center method; the optimal section slug volume ratio of the single well injected with two slugs under the heterogeneity of the permeability of the strata is calculated; and the objective function is established by combining the coefficient of variation of remaining oil saturation, the effect of chemical flooding and the cost, and the numerical simulator is used to optimize the objective function.

Chemical flooding method for balanced displacement of heterogeneous oil reservoir

An encapsulated polymer flooding method and system for enhancing oil recovery includes: (1) determining reservoir parameters, a well deployment, and a development dynamic state of a target oil reservoir; (2) determining a near-wellbore targeted profile control area and a far-wellbore targeted viscosification area; (3) designing and synthesizing an encapsulated polymer according to conditions of the target oil reservoir; (4) evaluating and determining whether the anti-shearing performance, the sustained release and viscosification performance, the injection performance, and the profile control performance of the encapsulated polymer meet expected performance requirements based on laboratory tests; (5) formulating an injection scheme for an encapsulated polymer flooding field; and (6) monitoring the development dynamic state of the oil reservoir; according to the present disclosure, the polymer is wrapped with a shell layer, which greatly reduces the shear degradation during injection of the polymer and effectively reduces the cost.

Encapsulated polymer flooding method and system for enhancing oil recovery

The application relates to the technical field of oil and gas field development, and discloses a correction method and system for a permeability model considering gas hydrate distribution, and a method and system for determining the permeability of the hydrate-bearing porous medium. The correction method includes: calculating a water mass and a hydrate saturation of each subregion of a porous medium in a dissociation process of a gas hydrate; calculating an average permeability of the porous medium in the dissociation process of the gas hydrate according to the hydrate saturation and a permeability model, wherein a value of a permeability characteristic parameter in the permeability model is an initial value of the permeability characteristic parameter; and determining the initial value of the permeability characteristic parameter as an optimal value of the permeability characteristic parameter under a condition that an difference between the average permeability of the porous medium and an actually measured permeability in the dissociation process of the gas hydrate is less than or equal to a preset value. In the application, through the corrected permeability model, the permeability characteristics of the porous medium considering the heterogeneous distribution of the hydrate can be accurately measured.

Method for correcting permeability model of porous medium in dissociation process of gas hydrate, and method and system for determining permeability of hydrate-bearing porous medium

A method for improving the gas recovery of a natural gas hydrate reservoir by using artificial impermeable layers is described. Artificial impermeable layers are formed by injecting cement slurry into the permeable overburden and underburden layers. When depressurization exploitation is performed, a large amount of seawater can be effectively blocked from entering a hydrate layer, and a production pressure difference between the hydrate layer and the production well is effectively increased, so that a hydrate decomposition rate and the gas recovery are improved.

Method for enhancing gas recovery of natural gas hydrate reservoir

A daily gas production rate of a methane hydrate deposit is calculated based on inflow performance relationship formulas. Step 1 determines the production stage, including the gas production rate trend of a production test and selecting an inflow performance relationship formula corresponding to the stage. Step 2 calculates basic coefficient terms related to energy conversion in the inflow performance relationship formula. Step 3 obtains other coefficient terms related to production in the inflow performance relationship formula. Step 4 predicts the gas production rate under other production pressure differences. Staged inflow performance relationship formulas characterize the complex methane hydrate deposit production performance. Gas production rate and deposit pressure under a large pressure differences are predicted through simple production tests under a small pressure difference, providing a basis for production design of the hydrate deposit and preventing accidents that may be caused by direct production under a large pressure difference.

Method for calculating daily gas production rate of methane hydrate deposit based on inflow performance relationship formulas

The disclosure discloses a method for obtaining formation parameters of a gas hydrate reservoir through well testing interpretation, which comprises: (1) establishing a physical model for well testing interpretation of the gas hydrate reservoir according to multiphase flow, hydrate dissociation, secondary hydrate formation and heat transfer exhibited in the well testing process of the gas hydrate reservoir; (2) establishing a mathematical model for well testing interpretation of the gas hydrate reservoir; (3) conducting spatial discretization and temporal discretization on the mathematical model, and adopting a finite volume method to obtain a numerical solution of bottom-hole pressure; (4) calculating a bottom-hole pressure variation curve and a production rate variation curve in the well testing process of the hydrate reservoir, and drawing theoretical curves of bottom-hole pressure difference and pressure difference derivative; and (5) matching a measured pressure curve with the theoretical curve to obtain the relevant formation parameters.

Method for obtaining formation parameters of gas hydrate reservoir through well testing interpretation

Disclosed is a method for simulation of a microscopic flow of pre-crosslinked gel suspension liquid in a porous medium, including the steps of: establishing a simulation area of the porous medium based on a two-dimensional core CT slice image and subjecting the simulation area to numerical grid discretization; setting initial position and original shape of pre-crosslinked gel particles to generate virtual boundary mark points; marking the type of numeric grid nodes; calculating the force of the fluid on each virtual boundary mark point according to the momentum change of the numerical grid nodes on the boundary of the pre-crosslinked gel particles; calculating the contact force on each virtual boundary mark point using a particle contact action model; calculating the bending recovery force and the stretching recovery force for each virtual boundary mark point based on the current shape and original shape of the pre-crosslinked gel particles; and calculating the velocity and displacement of each virtual boundary mark point based on Newton's second law, wherein the respective virtual boundary mark points are connected to obtain the overall shape and position of the pre-crosslinked gel particles.

Method for simulation of microscopic flow of pre-crosslinked gel suspension liquid in porous medium

The example of implementation of the invention provides a method used for exploiting a natural gas hydrate reservoir and belongs to the field of natural gas hydrate reservoir exploitation. The method mainly comprises a heat-injecting vertical well and a production horizontal well. The production horizontal well is opened in a segmental manner. In combination with natural gas hydrate heat exploitation, heat flow injected into the vertical well is enabled to heat different positions of the natural gas hydrate reservoir to increase a recovery ratio of the natural gas hydrate reservoir. The method specifically comprises the steps of injecting a heat flow into the natural gas hydrate reservoir by utilizing the vertical well to promote decomposition of the hydrate; firstly opening a horizontal branch of the horizontal well fully and keeping depressurization exploitation. When gas production amount is reduced to a certain degree, dividing a segmentation number based on permeability of the natural gas hydrate reservoir and performing segmental exploitation on the horizontal branch from a toe end to a heel end to realize heat exploitation of the heterogeneous natural gas hydrate reservoir. The method makes full use of a horizontal well structure, reduces exploitation cost and provides effective measures for efficient exploitation of the heterogeneous natural gas hydrate reservoirs.

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Qingdao, China

Jian Hou