非均质底水气藏水平井井筒流量及压力剖面研究

在非均质底水气藏开发过程中,水平井钻遇不同渗透率的储层是影响水平井井筒流量以及压力剖面的重要因素.以非均质底水气藏水平井渗流理论研究为基础,利用微元法将非均质储层分为若干均质储层,并在每个均质区域考虑储层与井筒耦合的变质量流动,建立了求解非均质底水气藏产量以及压力剖面的半解析模型.实例分析表明,水平井井筒流量剖面随着渗透率分布的变化出现不同幅度的波动,渗透率级差越大,流量剖面波动的范围越大,且水平井钻遇高渗透储层越多,总产量也越大;在水平井井筒跟端与趾端附近,渗透率分布对井筒压力剖面基本无影响,而在水平井井筒中间部分,高渗透储层分布越多,压降越大,反之则压降越小,但整个水平井井筒压降仅为10-4 MPa左右,因此水平气井压力测试只需将压力计下到井筒跟端处.

Study on the flow rate and pressure profile of horizontal well in heterogeneous gas reservoir with bottom water

During the developing the heterogeneous gas reservoir with bottom water, the distribution of different permeability along the wellbore will be an important factor which influences the flow rate profile and pressure profile. Based on the theory of seepage flow of horizontal well in heterogeneous gas reservoir with bottom water, this paper used infinitesimal method to divide the heterogeneous formation into several homogeneous formations, established the coupling model between formation and wellbore, which considered the variable mass flow in the wellbore, and established the semi-analytic model of flow rate profile and pressure profile of horizontal well in gas reservoir with bottom water. Case study shows that the flow rate profile presents different fluctuation as the changing distribution of permeability along the wellbore, the larger the value of Kh max/Kh min is, the larger the fluctuation range will be, meanwhile during drilling, if wellbore has drilled many high permeability formations, the production of horizontal well will be higher;near the toe and heel of horizontal well, the distribution of permeability has no influence on pressure profile, while in the middle of the wellbore, the larger the number of high permeability formation is, the greater the pressure drop in the wellbore will be and vice versa; the pressure drop along the total wellbore is very smaller, just 10-4 MPa, so during well testing, the pressure gage should only put at the heeling of the wellbore.