The “fracture-controlled reserves” based stimulation technology for unconventional oil and gas reservoirs

Lei, Qun; Yang, Lifeng; Duan, Yonghong; Weng, Dingwei; Wang, Xin; Guan, Bowen; Zhen, Wang; Guo, Ying

doi:10.1016/s1876-3804(18)30080-6

Cited by 27 publications

(13 citation statements)

References 12 publications

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“…Therefore, magnesium alloy has good solubility, high specific strength, high specific stiffness, and good machining performance, 30 which can meet the mechanical strength requirements of volume fracturing with small section size and is easy to manufacture. Its density is 1.78 g/cm 3 , only 1/4 of steel, and the residue is easy to discharge from the wellbore, meeting the fracturing design requirements for different well conditions and reservoirs.…”

Section: Dissolution Rate Control and Analysis Of Magnesium-based Alloymentioning

confidence: 95%

“… 2 Since 2010, new ideas of “volume fracturing” and “fracture-controlled reserves” transformation method have been implemented to form the “horizontal well casing completion and cluster perforation and frac plug section,” the body of the fracturing process. 3 However, with the increase of fracturing scale and well number, there would be more and more slight casing deformations in some well sections due to various reasons. According to incomplete statistics, the average casing loss rate of shale gas horizontal wells in Changning, Wei 202, Wei 204, and Zhaotong blocks in China reached 38.46% at the end of 2019 and 30.4% at the end of 2020 in Ma#56 tight oil block in Santanghu Basin.…”

Section: Introductionmentioning

confidence: 99%

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Study and Field Trials on Dissolvable Frac Plugs for Slightly Deformed Casing Horizontal Well Volume Fracturing

Zhang

Wang

2022

ACS Omega

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In view of the need for slightly deformed casing horizontal well fracturing, a new dissolvable frac plug has been designed using mechanical and material methods. The results of simulation analysis, laboratory research, and field test verification show that: (1) the integral half-split inlaid tooth slip and implicit-shaped single sealing element are adopted. Under the same pressure resistance index, the outer diameter and the total length of the frac plug are small, the inner diameter is big, and the pressure resistance downhole passing performance are better. (2) Using dissolvable magnesium-based powder, hydrogenated butadiene-acrylonitrile rubber, fluororubber polyglycolic acid, and the cellulose fiber and coating process, the solubility of the frac plug is observed to be more reliable. (3) Using the structural modular design, the frac plug has outstanding advantages in terms of on-site installation, preventing early seat sealing, self-separation after release, less dissolvable matter, and so on. (4) The finite element simulation and physical simulation experiments show that 121.36 mm ID casing with the frac plug can tolerate deformation in the range of 15 mm, which meets the needs for the casing usage. The temperature increases from 60 to 98 °C, and the maximum sustainable pressure differential decreases from 7.6 to 11.2 h at 70 MPa without any leakage. The frac plug can be completely dissolved within 300 h, and the final size of the residual solid is less than 0.3 mm. (5) In field trials of eight wells, through the minimum set of change inner diameter of 107 mm, the maximum wellhead fracturing pressure is 83.9 MPa in the formation, with the temperature ranging from 36 to 110 °C, and the plug can be completely self-dissolved in 16 days (the shortest time that has been found). After the fracturing operation with this dissolvable frac plug, the average daily oil production is maintained as high as 10.45 t with 22,000 m 3 gas production. A new dissolvable frac plug tool solves the problem of continuous fracturing in slightly casing variable wells, restores the full bore of the wellbore after staged fracturing, and realizes the production of oil and gas wells without drilling plug and the smooth implementation of follow-up measures. It has a wider application range, higher efficiency, safety, and economy. It is of great significance for industrialized staged fracturing of unconventional oil and gas horizontal wells and platform wells.

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Section: Dissolution Rate Control and Analysis Of Magnesium-based Alloymentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Study and Field Trials on Dissolvable Frac Plugs for Slightly Deformed Casing Horizontal Well Volume Fracturing

Zhang

Wang

2022

ACS Omega

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“…In order to describe the special percolation process of tight reservoir, the model is simplified as a single fracture. At this time, the flow process of crude oil is divided into three stages: the flow in matrix (non-linear flow from matrix to fracture wall), the flow from fracture wall to wellbore (plane radial flow) and the flow in wellbore (pressure drop due to resistance along the way) (Qun et al, 2018). In the solution process, the first two processes are coupled to obtain the equivalent radius of the vertical well and the equivalent diameter in the presence of a single fracture.…”

Section: Establishment Of Steady-state Productivity Modelmentioning

confidence: 99%

The characteristics of unconventional tight oil reservoir and its modification technology and productivity prediction

et al. 2021

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The zonal productivity prediction model of volume fractured horizontal wells in tight reservoirs is established in this study based on the physical model of volume fractured horizontal wells to study the near-well seepage law of volume fractured horizontal wells in unconventional tight reservoirs. The conformal transformation and iteration method are used to solve the problem. Compared with Fan Zifei's and Ning Zhengfu's method, the optimization of fractured horizontal wells' production parameters is studied. The effects of starting pressure gradient and fracture cluster number on horizontal wells' productivity with volume fracturing are analyzed. Multivariate regression analysis is used to rank the importance of influencing factors. The results show that the starting pressure gradient has the most significant impact on capacity. The application example of volume fractured horizontal wells in Lucaogou tight reservoir shows that the zonal productivity model established in this study can be used to predict the initial productivity of volume fractured horizontal wells. Thus, through theoretical analysis and numerical simulation, the productivity prediction model of horizontal wells with volume fracturing has certain guiding significance for the effective development of tight reservoirs.

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“…Low-permeability oil and gas reservoirs have become important exploratory and development fields in the world (Zou et al 2017;Mu and Ji 2019). Horizontal well small-hole fracturing technology is an important production stimulation measure for low-permeability oil and gas reservoirs (Lei et al 2018;Qu et al 2019;Agarwal et al 2019). In reservoirs, the expansion packer determines the outcomes of the fracturing technology.…”

Section: Introductionmentioning

confidence: 99%

Multi-objective optimization and experiment of nylon cord rubber in expandable packer

et al. 2021

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Nylon cord rubber has the advantages of small residual deformation and is easy to lift and lower the tubing string in low-permeability oil and gas reservoirs. However, it is associated with low-pressure resistance and poor sealing performance. To enhance the performance of nylon cord rubber, a three-dimensional numerical model of the nylon cord rubber was established and its accuracy experimentally determined. The Plackett–Burman test, the Steepest climbing test and the Response surface method were used to acquire the polynomial response surface model connecting structural parameters with bearing and sealing pressure. Using genetic algorithms, optimal structural parameters of nylon cord rubber were determined depending on field operation. The reliability of the optimized results was verified by laboratory tests. It was shown that after optimization, the bearing capacity of the expandable packer increased by 25% while the sealing performance increased by 66%. In addition, the bearing pressure was 70 MPa while the sealing pressure was 50 MPa. These measurements effectively met the on-site requirements of high-pressure and fine fracturing in low-permeability oil and gas reservoirs.

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The “fracture-controlled reserves” based stimulation technology for unconventional oil and gas reservoirs

Cited by 27 publications

References 12 publications

Study and Field Trials on Dissolvable Frac Plugs for Slightly Deformed Casing Horizontal Well Volume Fracturing

Study and Field Trials on Dissolvable Frac Plugs for Slightly Deformed Casing Horizontal Well Volume Fracturing

The characteristics of unconventional tight oil reservoir and its modification technology and productivity prediction

Multi-objective optimization and experiment of nylon cord rubber in expandable packer

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