A method for determining reservoir physical property and fracture characteristic parameters by using pressure drop data during horizontal well soaking period

Abstract

The application discloses a kind of to utilize horizontal well during the determination method of evaluation reservoir physical property and fracture characteristic parameter of pressure drop data stewing well, comprising: obtaining target well, and setting electronic pressure gauge at wellhead;After the target well is implemented stewing well after pressure, and pressure drop test is carried out;After stewing well reaches preset time, read wellhead electronic pressure gauge;Collect and organize target well data, respectively carry out data preprocessing for fracturing injection process and stewing well pressure drop process;Based on seepage infiltration mechanism, combine stewing well parameter modeling, obtain the flow characteristics of reservoir stage during the stewing well of horizontal well, and then determine the test model selection standard;Plot well test interpretation pressure and pressure derivative double logarithmic curve, carry out well test comprehensive interpretation and analysis, obtain the basic information of test well.The application can quickly evaluate reservoir porosity and permeability characteristics, fracturing reconstruction effect, provide support for horizontal well reconstruction parameter optimization, well spacing design deployment, subsequent drainage technology selection and the like.

Description

Technical Field

[0001] This invention relates to the field of oil and gas development technology, specifically to a method for evaluating reservoir properties and fracture characteristics using pressure drop data during horizontal well shut-in, applicable to the rapid evaluation of reservoir porosity and permeability in target wells undergoing shut-in after horizontal well pressure. Background Technology

[0002] The oil and gas industry is vital to the nation's development, making research on related technologies for oil and gas exploration and development of paramount importance. Horizontal wells are one of the main methods of oil and gas field development. Currently, the mainstream understanding is to implement well-shutting after large-scale fracturing of horizontal wells, allowing the injected fluid to permeate and exchange oil with the reservoir, thus fully utilizing the remaining energy from fracturing and the original energy of the reservoir. This is particularly true for low-permeability, ultra-low-permeability, and extra-low-permeability reservoirs, where large-scale volumetric fracturing of horizontal wells is commonly used, combined with post-fracturing well-shutting to achieve efficient development. For these types of fracturing wells, rapid evaluation of the reservoir porosity and permeability characteristics after fracturing is helpful for optimizing fracturing parameters and selecting subsequent drainage technologies, thereby improving the level of oilfield exploration and development.

[0003] Currently, the post-fracturing reservoir porosity and permeability characteristics are mainly evaluated through small-scale fracturing tests and pump shutdown pressure drop tests. However, during horizontal well fracturing, whether it is a small-scale fracturing test or a pump shutdown pressure drop test after the main fracturing operation, the test time generally only lasts for a few hours. During the test period, the fractures are not completely closed, and the evaluation results cannot truly reflect the degree of reservoir modification caused by fracturing. Therefore, it is difficult to meet the need for rapid evaluation of the post-fracturing (after fracture closure) reservoir porosity and permeability characteristics. Summary of the Invention

[0004] The purpose of this invention is to provide a method for evaluating reservoir properties and fracture characteristics using pressure drop data during the shunting period of a horizontal well. This method is specifically designed for large-scale fractured horizontal wells undergoing shunting, and involves pressure drop testing.

[0005] To achieve the above objectives, this application proposes a method for evaluating reservoir properties and fracture characteristic parameters using pressure drop data during horizontal well shut-in, comprising:

[0006] Obtain the target well and install an electronic pressure gauge at the wellhead;

[0007] The target well was subjected to post-pressure sealing and pressure drop testing.

[0008] After the well has been sealed for the preset time, the pressure of the electronic pressure gauge at the wellhead is read.

[0009] Collect and organize target well data, and perform data preprocessing for the fracturing injection process and the well shut-in pressure drop process respectively;

[0010] Based on the seepage and absorption mechanism and combined with well-steaming parameter modeling, the reservoir flow characteristics during the well-steaming period of horizontal wells are obtained, and then the selection criteria for well test models are determined.

[0011] Plot double logarithmic curves of well test interpretation pressure and pressure derivative, perform comprehensive interpretation and analysis of well tests, and obtain basic information about the test wells.

[0012] Furthermore, large-scale fracturing horizontal wells were selected as target wells.

[0013] Furthermore, the data preprocessing method for the fracturing injection process is as follows: based on the original reservoir physical property parameters and engineering design parameters, the fluid production capacity during the stable production period after fracturing is predicted, and the equivalent fracturing injection time and injection volume are determined according to the fluid production capacity during the stable production period after fracturing.

[0014] Furthermore, the engineering design parameters include reservoir utilization thickness, design fracture half-length, design fracture number, design fluid volume, and sand addition volume.

[0015] Furthermore, the data preprocessing method for the well sump pressure drop process is as follows: the pressure drop data during the well sump period is converted into pressure recovery data according to the time sequence and decreasing pattern.

[0016] Furthermore, the method for classifying the reservoir flow characteristics during the stagnation period of a horizontal well is as follows: based on the seepage and absorption mechanism and combined with stagnation parameter modeling, the reservoir oil-water replacement law during the stagnation period is obtained, and the main flow stage of the reservoir during the stagnation period after pressure is divided into three stages: well-storage, transition, and main replacement.

[0017] Furthermore, based on the aforementioned main flow stage, the selection criteria for the well pressure drop test interpretation model during the horizontal well shut-in period are obtained.

[0018] Furthermore, the selection criteria for the well test interpretation model during the pressure drop during horizontal well shut-in are as follows: the well reservoir model is the fixed well reservoir model, the well model is the horizontal well fracturing model, the reservoir model is the dual-hole quasi-steady-state model, and the boundary model is the infinite boundary model.

[0019] Furthermore, the basic information of the test well includes reservoir physical parameters, artificial fracture characteristic parameters, wellbore reservoir coefficient, etc.

[0020] Compared with the prior art, the above technical solution adopted in this invention has the following advantages: This invention provides a method for evaluating reservoir properties and fracture characteristic parameters using pressure drop data during horizontal well shut-in. Through field tests, relatively accurate evaluation results of post-fracturing reservoir porosity and permeability characteristics have been obtained, which has helped to form the 2.0 process technology of advanced energy storage and synchronous fracturing for tight oil horizontal wells. It has broad application prospects for the abundant tight oil resources in various oil fields. Attached Figure Description

[0021] Figure 1 This is a schematic diagram illustrating the predicted liquid production capacity during the stable production period after compression.

[0022] Figure 2 A schematic diagram of data preprocessing methods for the fracturing injection process;

[0023] Figure 3 A schematic diagram of the data preprocessing method for the well pressure drop process;

[0024] Figure 4 A schematic diagram for verifying the compliance rate of measured flow stages in the mine; Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit the application; that is, the described embodiments are only a part of the embodiments of this application, and not all of them.

[0026] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0027] The terms “comprising” and “having”, and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion, meaning that a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product, or apparatus.

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0029] Example 1

[0030] This embodiment provides a method for determining reservoir properties and fracture characteristics parameters using pressure drop data during horizontal well shut-in, specifically including:

[0031] Step 1. Obtain the target well and install an electronic pressure gauge at the wellhead;

[0032] Specifically, in the Songliao Basin, a large-scale fractured horizontal well (Well A5) in an unconventional oil reservoir was selected for post-compression shunting to interpret and evaluate the pressure drop data during the shunting period.

[0033] Step 2. Perform post-pressure well shut-off on the target well and conduct a pressure drop test;

[0034] Specifically, on May 20, 2021, an electronic pressure gauge was installed at the wellhead, and the well was shut off after pressure was applied to conduct a shut-off pressure drop test.

[0035] Step 3. After the well has been sealed for the preset time, read the pressure from the electronic pressure gauge at the wellhead;

[0036] Specifically, after the well shut-in time reaches the designed shut-in time of 54 days, the wellhead electronic pressure gauge is read to end the well test.

[0037] Step 4. Collect and organize target well data, and perform data preprocessing for the fracturing injection process and the well shut-in pressure drop process respectively;

[0038] Specifically, data on drilling and completion, coring, logging, fracturing operations, fluid sampling, and production dynamics of well A5 were collected and compiled.

[0039] The data preprocessing method for the fracturing injection process is as follows: Based on the original physical property parameters and engineering design parameters of well A5, a numerical model of the reservoir after the fracturing is established to predict the daily fluid production capacity of well A5 during the stable production period of 50m³ / h, under the condition of 2-3 years of well operation and bottom hole flowing pressure of 7-9 MPa. 3 The actual fracturing time of well A5 was 21 days, with a total daily injection volume of 1700 m³. 3 Based on the predicted liquid production capacity during the stable production period after compression, such as Figure 1 As shown; the equivalent fracturing injection time is 714 days and the daily injection volume is 50m³. 3 ,like Figure 2 As shown;

[0040] The data preprocessing method for the well stagnation pressure drop process is as follows: multiply the pressure drop data during the well stagnation period by -1 and mirror it on the X-axis. Then, according to the chronological order and decreasing pattern, convert it into equivalent pressure recovery data, such as... Figure 3 As shown;

[0041] Step 5. Based on the seepage and absorption mechanism, and combined with well-shutdown parameter modeling, the reservoir flow characteristics during the well-shutdown period of a horizontal well are obtained, thereby determining the selection criteria for the well test model, such as... Figure 4 As shown;

[0042] Specifically, based on the seepage and absorption mechanism and combined with well-steaming parameter modeling, the reservoir oil-water replacement law during well-steaming is obtained, and the main flow stage of the reservoir during well-steaming after pressure is divided into three stages: well-storage, transition, and main replacement.

[0043] Based on the defined flow stages, selection criteria were established for interpreting well pressure drop test models during horizontal well shut-in periods. For example, the well reservoir model was selected as the fixed well reservoir model, the well model as the horizontal well fracturing model, the reservoir model as the dual-hole quasi-steady-state model, and the boundary model as the infinite boundary model. The flow stages were compared with field measured data, and the consistency rate was high.

[0044] Step 6. Plot the double logarithmic curves of modern well test interpretation pressure and pressure derivative, perform comprehensive interpretation and analysis of well tests, and obtain basic information about the test well (Table 1).

[0045] Table 1. Evaluation of reservoir properties and fracture characteristics parameters during horizontal well shut-in.

[0046] numerical values 2.75 1748 -8.15 31.1 6.5 180 145 30 6.27 unit <![CDATA[m 3 / MPa]]> m / MPa m strip m m md

[0047] This invention provides a method for determining reservoir properties and fracture characteristics based on pressure drop data during the well-shutdown period of horizontal wells. It addresses the relative lack of rapid evaluation methods for the post-fracturing effects of horizontal wells by preprocessing data from both the fracturing injection process and the well-shutdown pressure drop process to conform to well test interpretation standards. This allows for rapid evaluation of reservoir porosity and permeability characteristics and fracturing effects, providing support for optimizing horizontal well stimulation parameters, designing well spacing, and selecting subsequent drainage technologies.

[0048] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for determining reservoir properties and fracture characteristics parameters using pressure drop data during horizontal well shut-in, characterized in that, include: Obtain the target well and install an electronic pressure gauge at the wellhead; The target well was subjected to post-pressure sealing and pressure drop testing. After the well has been sealed for the preset time, the pressure of the electronic pressure gauge at the wellhead is read. Collect and organize target well data, and perform data preprocessing for the fracturing injection process and the well shut-in pressure drop process respectively; Based on the seepage and absorption mechanism and combined with well-steaming parameter modeling, the reservoir flow characteristics during the well-steaming period of horizontal wells are obtained, and then the selection criteria for well test models are determined. Plot double logarithmic curves of well test interpretation pressure and pressure derivative, perform comprehensive interpretation and analysis of well tests, and obtain basic information about the test wells; The data preprocessing method for the fracturing injection process is as follows: based on the original reservoir physical property parameters and engineering design parameters, predict the fluid production capacity during the stable production period after fracturing, determine the equivalent fracturing injection time and injection volume according to the fluid production capacity during the stable production period after fracturing, and move the pressure drop starting point to the closing pressure or below the closing pressure. The data preprocessing method for the well stagnation pressure drop process is as follows: the pressure drop data during the well stagnation period is converted into pressure recovery data according to the time sequence and decreasing pattern.

2. The method for determining reservoir properties and fracture characteristics parameters using pressure drop data during horizontal well shut-in as described in claim 1, characterized in that, Large-scale fracturing horizontal wells were selected as the target wells.

3. The method for determining reservoir properties and fracture characteristics parameters using pressure drop data during horizontal well shut-in as described in claim 1, characterized in that... The engineering design parameters include reservoir utilization thickness, design fracture half-length, design fracture number, design fluid volume, and sand addition volume.

4. The method for determining reservoir properties and fracture characteristics parameters using pressure drop data during horizontal well shut-in as described in claim 1, characterized in that, The method for classifying the reservoir flow characteristics during the stagnation period of a horizontal well is as follows: based on the seepage and absorption mechanism and combined with the stagnation parameter modeling, the reservoir oil-water replacement law during the stagnation period is obtained, and the main flow stage of the reservoir during the stagnation period after pressure is divided into three stages: well-storage, transition, and main replacement.

5. The method for determining reservoir properties and fracture characteristics parameters using pressure drop data during horizontal well shut-in as described in claim 4, characterized in that... Based on the main flow stage, the selection criteria for the well pressure drop test interpretation model during the horizontal well shut-in period are obtained.

6. The method for determining reservoir properties and fracture characteristics parameters using pressure drop data during horizontal well shut-in as described in claim 5, characterized in that... The selection criteria for the well test interpretation model during the pressure drop test of a horizontal well during the well shut-in period are as follows: the well reservoir model is the fixed well reservoir model, the well model is the horizontal well fracturing model, the reservoir model is the dual-hole quasi-steady-state model, and the boundary model is the infinite boundary model.

7. The method for determining reservoir properties and fracture characteristics parameters using pressure drop data during horizontal well shut-in as described in claim 5, characterized in that... The basic information of the test well includes reservoir physical parameters, artificial fracture characteristic parameters, and wellbore reservoir coefficient.

Images