不同水力压裂顺序下煤层气井组应力干扰效应研究—以沁水盆地柿庄南区块为例

Stress interference effects of coalbed methane well groups under different hydraulic fracturing sequences: Taking the Shizhuangnan block in Qinshui Basin as an example

摘要:

煤层气井常采用井网布置方式进行开发，不同的水力压裂顺序引起不同的应力干扰效应。为了查明不同水力压裂顺序下煤层气井间应力干扰效应，本文以沁水盆地柿庄南区块3组煤层气井网15口井为研究对象，应用ABAQUS 有限元模拟软件，模拟了煤层气井网中3种水力压裂顺序（先周围后中心、对角、先中心后周围）的应力分布特征及干扰效应，提出了相应的水力压裂顺序建议。结果表明：当施工排量为6.00 8.00 m3/min，液量为430.00 580.00 m3时，（1）先周围后中心、对角、先中心后周围压裂时，距中心井、对角线井、周围井不同距离，依次分为应力释放区、集中区和原始应力区。先周围后中心压裂时，中心井三区范围依次为≤15.00 m、15.00 140.00 m、＞140.00 m。对角压裂时，对角线井三区范围依次为≤60.00 m、60.00 150.00 m、＞150.00 m。先中间压裂时，周围井三区范围依次为≤60.00 m、60.00 144.00 m、＞144.00 m。（2）煤层气井网采用四点法布置，井间距超过300.00 m，可有效避免煤层气井之间的应力干扰。降低煤层气井压裂时的施工难度。

Abstract:

Coalbed methane wells are often developed using well network layout, and different hydraulic fracturing sequences will cause different stress interference effects. In order to identify the stress interference effects between coalbed methane wells under different hydraulic fracturing sequences, this work studied 15 wells in three groups of coalbed methane well networks in the Shizhuangnan block of Qinshui Basin, and utilized ABAQUS finite element simulation software to simulate the stress distribution characteristics and interference effects under three hydraulic fracturing sequences (first surrounding then center, diagonal, first center then surrounding) in the coalbed methane well networks. Corresponding hydraulic fracturing sequence suggestions were proposed. The results show that when the construction displacement is 6.00~8.00 m/min and the liquid volume is 430.00~580.00 m', (1) when fracturing around first, then around the center, diagonally, and then around the center, different distances from the center wells, diagonal wells, and surrounding wells can be divided into stress release zone, concentration zone, and original stress zone in sequence. When the surrounding area is first followed by the center, the range of the three zones of the central wells is ≤15.00 m, 15.00~140.00 m, and >140.00 m, respectively. During diagonal fracturing, the range of the three zones of the diagonal well is≤60.00 m, 60.00~150.00 m, and >150.00 m, respectively. When fracturing in the middle, the range of the three zones around the well is≤60.00 m, 60.00~ 144.00 m, and > 144.00 m, respectively. The coalbed methane well network is arranged using the four point method, with well spacing exceeding 300.00 m, which can effectively avoid stress interference between coalbed methane wells, and reduce the construction difficulty during coal seam well fracturing.