Experimental Study on a Liquid-Solid Phase-Change Autogenous Proppant Fracturing Fluid System

Yixin Chen; Yu Sang; Jianchun Guo; Jian Yang; Weihua Chen; Ji Zeng; Botao Tang; Tintin He

doi:10.1021/acsomega.2c04853

Experimental Study on a Liquid-Solid Phase-Change Autogenous Proppant Fracturing Fluid System

ACS Omega. 2023 Mar 1;8(10):9101-9110. doi: 10.1021/acsomega.2c04853. eCollection 2023 Mar 14.

Authors

Yixin Chen¹, Yu Sang¹, Jianchun Guo², Jian Yang¹, Weihua Chen¹, Ji Zeng¹, Botao Tang¹, Tintin He¹

Affiliations

¹ PetroChina Southwest Oil and Gas Field Company, No. 3, Section 1, Fuqing Road, Chenghua District, Chengdu, Sichuan 646002, China.
² Southwest Petroleum University, No. 8 Xindu Road, Xindu District, Chengdu, Sichuan 610500, China.

Abstract

In this paper, a liquid-solid phase-change autogenous proppant fracturing fluid system (LSPCAP) was proposed to solve the problems that was caused by "sand-carrying" in conventional fracturing technology in oil and gas fields. The characteristic of the new fluid system is that no solid particles will be injected in the whole process of fracturing construction except liquids. The fluid itself will transform into solid particles under the formation temperature to resist the closure stress in the fractures. There are two kinds of liquids that make up the new fracturing fluid system. One of the liquids is called phase-change liquid (PCL) which occurs in the liquid-solid phase change under the formation temperature to form solid particles. Another is called nonphase-change liquid (NPCL) which controls the dispersity and size of PCL in the two-phase fluid system. Based on the molecular interaction theory and organic chemistry, bisphenol-A epoxy resin was selected as the building unit of the PCL, and the NPCL consisted of deionized water + nonionic surfactant. The test results indicated that the new fracturing fluid shows the properties of non-Newtonian fluid and has no wall-building property. The new fluid system has good compatibility with the formation fluid, conventional fracturing fluid, and hydrochloric acid. Through the filtration test, the filtration coefficients of PCL, NPCL, and mixture are found to be 1.56 × 10^-4 m/s^1/2, 2.66 × 10^-4 m/s^1/2, and 1.7 × 10^-4 m/s^1/2, respectively, and the damage rate of mixture and NPCL is 18 and 17.7%. The friction test results show that the resistance reduction rate reaches 69% when the volume ratio of PCL and NPCL is 1:10. The shear rate and time only affect the size of the autogenous solid particles, and the sorting coefficient (S) of the particles is 1.04-1.73, indicating good sorting. Crushing resistance and conductivity test results show that the crush rate of autogenous solid particles is 3.56-8.42%. The conductivity of the autogenous solid particles is better than those of quartz sand and ceramsite under a pressure of 10-30 MPa.