<p>The essence of many issues in different fields is the transport and piling of particles in fluid within a limited space. A semi-analytical model is developed in this study to describe the motions of a particle in fluid and simulate the piling process of particles in a fracture. As a result, the configuration of a particle pile and the time at which the pile totally seal the fracture face are predicted. This model possesses a wide range of applications. Two types of applications of this model are introduced, including the prediction of proppant screen-out in hydraulic fracturing vertical and horizontal wells and the simulation of curing the lost circulation. Results of case studies are consistent with the field data with minor errors. Sensitivity analyses with the proposed model were conducted for each type of application. Major factors affecting the model calculation results are identified for the purpose of optimizing the performance of hydraulic fracturing and curing the lost circulation. Sensitivity analyses conducted for the proppant screen-out prediction during fracturing vertical and horizontal wells indicate following conclusions: 1) The use of high fluid viscosity can avoid the premature settlement of proppant and significantly delay the screen-out time. 2) The sse of proppant with low density in the practical range could delay the screen-out time, but the effect is not as significant as other factors analyzed in this study. 3) A high injection rate allows the proppant pile to build farther from the wellbore, while it will lead to a quick screen-out. 4) Larger proppant size can easily cause screen-out sooner. 5) Wide distributionof proppant size can delay screen-out. 6) The use of low ratio of proppant volume to fluid volume can minimize the probability of the occurrence of screen-out. Sensitivity analyses for the cure of lost circulation demonstrate following conclusions: 1) Lost circulation can be cured faster when low fluid viscosity is used. 2) High density LCM can facilitate the cure of lost circulation. 3) Low mud density can mitigate lost circulation, but its effect is not as significant as other factors. 4) The concentration of LCM should be determined based on the severity of lost circulation.
This semi-analytical model provides engineers a general tool to solve different issues involved in different fields. It can also be utilized to identify main factors responsible for different issues to minimize their detrimental effects.
| Identifer | oai:union.ndltd.org:PROQUEST/oai:pqdtoai.proquest.com:10816473 |
| Date | 11 April 2019 |
| Creators | Cai, Xiao |
| Publisher | University of Louisiana at Lafayette |
| Source Sets | ProQuest.com |
| Language | English |
| Detected Language | English |
| Type | thesis |
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