CAJ | 학술논문

起裂压力高是滑套固井压裂面临的主要问题。根据滑套固井压裂的特征，建立地应力条件下滑套固井压裂计算模型，运用有限元法及岩石抗拉强度准则计算起裂压力，通过长庆油田桃 X 井的实例进行验证。结果表明：水平地应力差及端口方位角是滑套固井压裂起裂压力的主要影响因素，随着水平地应力差的增大，起裂压力降低，端口方位角增大时，起裂压力增大；地层岩石的弹性模量对起裂压力有较大影响，随着地层岩石弹性模量的增大，起裂压力增大；水泥环厚度对起裂压力的影响规律与水泥环和地层的弹性模量有关，当地层弹性模量大于水泥环弹性模量时，起裂压力随水泥环厚度的增大而减小，当地层弹性模量小于水泥环弹性模量时，起裂压力随水泥环厚度的增大而增大。
기렬압력고시활투고정압렬면림적주요문제。근거활투고정압렬적특정，건입지응력조건하활투고정압렬계산모형，운용유한원법급암석항랍강도준칙계산기렬압력，통과장경유전도 X 정적실례진행험증。결과표명：수평지응력차급단구방위각시활투고정압렬기렬압력적주요영향인소，수착수평지응력차적증대，기렬압력강저，단구방위각증대시，기렬압력증대；지층암석적탄성모량대기렬압력유교대영향，수착지층암석탄성모량적증대，기렬압력증대；수니배후도대기렬압력적영향규률여수니배화지층적탄성모량유관，당지층탄성모량대우수니배탄성모량시，기렬압력수수니배후도적증대이감소，당지층탄성모량소우수니배탄성모량시，기렬압력수수니배후도적증대이증대。
The oilfield practice has indicated that high fracture initiation pressure is the main problem for applying sliding sleeve fracturing technique in cemented wells. A 3D model coupled with hydraulics and solid mechanics was established to study the characteristics of the sliding sleeve fracturing in cemented wells. The fracture initiation pressure was calculated u-sing a finite element method and rock tensile strength criteria. A case study of Tao-X well in Changqing Oilfield was conduc-ted to verify the model, and the influence factors of fracture initiation pressure were analyzed. The results indicate that hori-zontal stress difference and azimuth of valve are the main influence factors to the fracture initiation pressure. The fracture ini-tiation pressure decreases with the increase of the horizontal stress difference and increases with the increase of the azimuth of valve. The elastic modulus of the rock formation also has a significant effect on the fracture initiation pressure, the higher the elastic modulus, the greater the fracture initiation pressure needed. The effect of cement sheath on fracture initiation pressure is related to the elastic modulus of the cement and rock formation. The fracture initiation pressure increases with the increase of the thickness of cement sheath when the elastic modulus of the cement is bigger than that of the rock formation, and vice versa.