【摘要】：水力壓裂可顯著提高頁(yè)巖氣等致密儲(chǔ)層巖體的滲透性以增加油氣產(chǎn)量,然而受多因素影響,水力壓裂形成縫網(wǎng)結(jié)構(gòu)的機(jī)理和壓裂優(yōu)化設(shè)計(jì)一直是研究的焦點(diǎn)和難點(diǎn)。本研究基于滲流-應(yīng)力-破壞耦合計(jì)算模擬方法,對(duì)不同水力加載條件下的非均質(zhì)儲(chǔ)層水力壓裂過(guò)程進(jìn)行了模擬和對(duì)比研究。研究結(jié)果表明:水力壓裂過(guò)程中起始注水壓力和增量大小對(duì)水力壓裂縫網(wǎng)擴(kuò)展和改造區(qū)域形態(tài)有著顯著的影響。當(dāng)起始注水壓力小于等于模型材料體抗拉強(qiáng)度,并緩慢增壓致裂時(shí),壓裂過(guò)程可近似視為穩(wěn)態(tài)應(yīng)力-破壞-滲流耦合作用過(guò)程的不同階段,這種情況下僅在壓裂井孔周圍形成兩組對(duì)稱式的傘狀水力裂縫帶。當(dāng)對(duì)模型體施加高于模型材料體破裂壓力的注水壓力時(shí),相當(dāng)于對(duì)壓裂孔快速施加高動(dòng)水壓力,水力裂縫沿壓裂孔全方位迅速萌生并快速擴(kuò)展,當(dāng)注水壓力值高于破裂壓力一定幅值時(shí),壓裂改造可形成圍繞壓裂井全方位的放射狀裂縫網(wǎng)絡(luò),使壓裂儲(chǔ)層得以最大范圍改造。在擬靜力和擬動(dòng)力兩種加載條件下,不同水巖相互作用機(jī)理是造成不同水力加載條件出現(xiàn)不同縫網(wǎng)結(jié)構(gòu)的力學(xué)機(jī)制,而對(duì)于實(shí)際的頁(yè)巖氣儲(chǔ)層改造,壓裂產(chǎn)生圍繞壓裂井全方位放射狀的縫網(wǎng)結(jié)構(gòu)則是一種最優(yōu)的體積壓裂改造。
[Abstract]:Hydraulic fracturing can significantly improve the permeability of tight rock mass, such as shale gas, in order to increase oil and gas production. However, due to the influence of many factors, the mechanism of hydraulic fracturing forming fracture network structure and the optimum design of fracturing have been the focus and difficulty of the research. Based on the coupled seepage stress-failure simulation method, the hydraulic fracturing process of heterogeneous reservoir under different hydraulic loading conditions was simulated and compared. The results show that the initial injection pressure and increment have a significant effect on the extension and reconstruction of hydraulic fracturing network in the process of hydraulic fracturing. When the initial injection pressure is less than or equal to the tensile strength of the model material and the fracture is caused by a slow increase of pressure, the fracturing process can be approximately regarded as the different stages of the steady state stress-failure seepage coupling process. In this case, only two sets of symmetrical umbrella hydraulic fracture zones are formed around the fracturing well hole. When the water injection pressure of the model body is higher than the fracture pressure of the model material body, it is equivalent to applying high dynamic water pressure to the fracturing hole quickly, and the hydraulic fracture is springing up and expanding rapidly along the fracturing hole. When the value of water injection pressure is higher than a certain amplitude of fracture pressure, the radial fracture network around the fracturing well can be formed by fracturing reconstruction, and the maximum range of fracturing reservoir can be reconstructed. Under two loading conditions, pseudostatic and pseudo-dynamic, different water-rock interaction mechanism is the mechanical mechanism which results in different fracture network structure under different hydraulic loading conditions, but for the actual shale gas reservoir transformation, Fracturing is a kind of optimal volume fracturing.
【作者單位】： 中國(guó)科學(xué)院地質(zhì)與地球物理研究所中國(guó)科學(xué)院頁(yè)巖氣與地質(zhì)工程重點(diǎn)實(shí)驗(yàn)室;中國(guó)科學(xué)院大學(xué);
【基金】：中國(guó)科學(xué)院戰(zhàn)略性先導(dǎo)科技專項(xiàng)(B類)(XDB10030602) 國(guó)家自然科學(xué)基金項(xiàng)目(41372325,41372323,41402280)資助
【分類號(hào)】：TE357.1
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本文編號(hào)：2171564