CAJ | 학술논문

针对致密气藏斜井筒压裂形成的倾斜缝，将裂缝离散为微元，推导了裂缝内部有限导流数值解；采用倾斜板源函数及势叠加原理得到了气藏流动解析解，通过将缝内流动和气藏流动在裂缝面上进行压力及流量耦合，建立了压裂倾斜缝不稳定流动模型。划分了流动阶段，给出了对应的拟压力或拟压力导数解析表达式，分析了储层及压裂参数对压力动态的影响。结果表明：不考虑井筒储存效应时，压裂倾斜缝流动形态分为：裂缝与地层双线性流、地层线性流、早期径向流、拟复合线性流和晚期拟径向流。井筒存储效应产生的井筒续流段会掩盖双线性流。裂缝倾斜角和储层渗透率各向异性对井底压力动态影响时间最长，会一直延续到晚期拟径向流阶段。无因次裂缝导流能力唯一决定了裂缝与地层双线性流和地层线性流的出现与否及持续时间。随着气藏厚度的增大，早期径向流的持续时间增加，拟复合线性流的出现时间推迟。最后，利用苏里格气田一口压裂定向井实例证明了该模型的正确性。
침대치밀기장사정통압렬형성적경사봉，장렬봉리산위미원，추도료렬봉내부유한도류수치해；채용경사판원함수급세첩가원리득도료기장류동해석해，통과장봉내류동화기장류동재렬봉면상진행압력급류량우합，건립료압렬경사봉불은정류동모형。화분료류동계단，급출료대응적의압력혹의압력도수해석표체식，분석료저층급압렬삼수대압력동태적영향。결과표명：불고필정통저존효응시，압렬경사봉류동형태분위：렬봉여지층쌍선성류、지층선성류、조기경향류、의복합선성류화만기의경향류。정통존저효응산생적정통속류단회엄개쌍선성류。렬봉경사각화저층삼투솔각향이성대정저압력동태영향시간최장，회일직연속도만기의경향류계단。무인차렬봉도류능력유일결정료렬봉여지층쌍선성류화지층선성류적출현여부급지속시간。수착기장후도적증대，조기경향류적지속시간증가，의복합선성류적출현시간추지。최후，이용소리격기전일구압렬정향정실예증명료해모형적정학성。
In view of the inclined hydraulic fracture formed by slant well fracturing,the numerical model for fracture flow was derived based on the discrete fracture segments and the analytical model for reservoir flow was established by combining slant plane source function and the superposition principle. A semianalytical model for inclined fracture was developed by coupling the numerical fracture flow model and the analytical reservoir flow model dynamically in this paper. The flow regimes were defined,the corresponding pressure or derivate analytical equations were derived and the effect of reservoir and fracture pa-rameters on transient responses was investigated. The results show that there are five flow regimes including fracture/formation bilinear flow,formation linear flow,early radial flow,pseudo-compound linear flow and later pseudo-radial flow for inclined fracture in the absence of the effect of wellbore storage. The wellbore afterflow caused by wellbore storage may mask the frac-ture/formation bilinear flow. The period of the effect of the inclination angle and permeability anisotropy on transient pressure is very long,which will last to later pseudo-radial flow. The existence and duration of fracture/formation bilinear flow and formation linear flow is only determined by dimensionless fracture conductivity. Finally,a field test in fractured directional well from Suliger Gas Field verified the validity of the model.