变压力扩展指数模型法在页岩气井递减分析中的应用  

Application of Variable-Pressure drop YM-SEPD method to the decline analysis of shale gas wells

作　　者：陈满[1,2] 谢维扬 张小涛 蒋鑫 蒋睿[1,2] 张舟 

机构地区：[1]中国石油西南油气田公司勘探开发研究院 [2]页岩气评价与开采四川省重点实验室 [3]四川页岩气勘探开发有限责任公司 [4]四川长宁天然气开发有限责任公司

出　　处：《天然气勘探与开发》2017年第4期79-84,共6页Natural Gas Exploration and Development

基　　金：国家科技重大专项"页岩气勘探开发关键技术"课题"南方海相页岩气开采试验"(编号:2012ZX05018-006)

摘　　要：近年来四川盆地页岩气的勘探开发取得了突破性的进展,水平井与体积压裂主体工艺技术被广泛应用于川南地区长宁区块的页岩气开发中。页岩气分段压裂水平井的产量递减规律与常规气井差异大:在初期的压裂液返排阶段,气井产量递减较快,与人造裂缝性低渗气藏气井的早期生产动态相近;后期由于页岩气的解吸附作用增强,气井长期处于低压低产阶段,产量递减慢。北美出现了多种针对页岩气井的产量递减分析方法,但这些方法局限于定压生产的假设,与页岩气井实际生产中受邻井压裂、地面管网建设等因素影响而出现的变压力变产量生产的情况不相符。通过引入压力重整产量,对扩展指数法进行改进,形成变压力扩展指数模型法(简称VP-YM-SEPD法,即Variable-Pressure drop YM-SEPD法)来解决页岩气井变压力生产数据分析的难题。应用VP-YM-SEPD法分析生产数据,需要气井生产史在半年以上,可以分析得到可靠的递减参数。该方法成功用于分析川南地区长宁区块一页岩气井的生产数据,解决了页岩气井变压力生产的递减分析难题。In recent years, breakthrough has been realized in the shale gas exploration and development in the Sichuan Basin, and the principal technologies of horizontal well and volumetric fracturing have been extensively applied to the shale gas development in Changning Block, southern Sichuan Basin. The production decline law of shale-gas staged fracturing horizontal wells is different from that of conventional gas wells. In the early stage, i.e., the stage of fracturing fluid fiowback, the production rate of gas well declines fast. And this phenomenon is similar to the early production performance of the gas wells in artificially fractured low-permeability gas reservoirs. In the late stage, the gas well is low in pressure and production rate for a long term and its production decline rate slows down for the desorption capacity of shale gas is increased. In the North America, there are many production decline analysis methods available for shale gas wells, but these methods are confined to the assumption of constant-pressure production, which is not in accor- dance with the actual situation of shale gas well whose pressure and production rate are variable due to the fracturing of its neighbor- ing wells and the construction of surface pipeline networks. In this paper, the stretched exponential production decline was modified by introducing the pressure to normalize the production rate, and thus the Variable-Pressure drop YM-SEPD （VP-YM-SEPD） method was developed to solve the difficulty in analyzing the variable-pressure production data of shale gas wells. When VP-YM-SEPD meth- od is used to analyze the production data, the production history of the gas well shall be at least half a year, so that the reliable decline parameters can be obtained. This method has been successfully applied to analyze the production data of one shale gas well in Chang- ning Block, southern Sichuan Basin, and it solves the decline analysis difficulty of variable-pressure production of shale gas wells.

关 键 词：页岩气 变压力生产 产量递减分析 扩展指数法 四川盆地 长宁区块 

分 类 号：TE319[石油与天然气工程—油气田开发工程]