产品展厅>>研发&服务>>多段体积压裂单段压裂井口压力压降模型建立

页岩油为致密油藏,常规压裂增产幅度小、难以达实现高效开发。多段多簇体积压裂工程工艺技术作为一种新兴技术成为页岩油、低渗油藏增产重要措施,是实现页岩油经济开发的重要手段。多段多簇体积压裂规模大、耗资大,压裂后如何正确评价和分析措施效果显得十分的重要。试井技术是确定裂缝半长、裂缝导流能力、地层渗透率、地层压力等的重要手段,以其工艺简单、费用低得到了广泛地应用。

国内外对常规压裂试井技术研究很多,试井方法较为完善,但是对页岩油藏大型体积分段压裂试井技术研究还处于起步阶段尝试阶段,渗流特征认识还不够深入,还未形成成熟解释方法。研究开发压裂改造效果试井评价技术,确定裂缝半长、裂缝导流能力、改造区地层渗透率、地层压力等,为压裂设计优化、高效开发成为试井技术需要解决的重要问题。

针对页岩油藏开发过程中水平井多段压裂技术,开展多段体积压裂单段压裂井口压力压降模型建立。主要技术内容包括:

单段压裂评价物理模型和数学模型建立理论方法研究,数学模型求解方法研究,建立压力响应特征曲线。

压力响应特征影响因素分析,明确压力曲线形态特征的主要控制因素,建立分析图版。

井口-井底压力折算方法研究,变流量、变密度及变黏度下的井筒垂直管流计算方法研究;复杂垂直管流的方程数学求解;滤波理论的消除水锤引起的压力数据波动方法研究。

井口压力精度和停泵时间对模型相应特征影响分析。

实测数据反演及地层参数方法研究。

本项目通过对压裂期间施工数据的分析研究,提出了停泵压降试井分析方法,并形成了相应的计算模块,从而到达确定压裂井裂缝半长、裂缝导流能力、改造区地层渗透率、地层压力等资料信息的目的,为页岩油体积压裂开发过程中的压裂效果评价提供了技术保障。本项目不仅提供了压裂效果评价手段,也提供了采用压裂数据开展地层评价的新方法,具有重要的应用价值,并且对这类数据分析无需增加测试成本,具有即时、准确、低成本的技术和经济优势。

Products>>Project Development>>Establishment of wellhead pressure drop model for multi-stage volume fracturing and single-stage fracturing

Shale oil is a tight reservoir and has low conventional fracturing production, it is difficult to achieve efficient development. As a new technology, multi-stage multi-cluster fracturing engineering technology has become an important measure to increase production of shale oil and low permeability reservoirs, and is an important means to realize the economic development of shale oil. Multi-stage multi-cluster fracturing has large scale and costs, so it is important to evaluate and analyze the effect. Well testing technology is an important means to determine the fracture half length, fracture conductivity, formation permeability, formation pressure and so on. It has been widely applied for its low cost and simple process.

There are many researches on conventional fracturing well test technology at home and abroad, and the well test method is relatively perfect, but the research on large volume staged fracturing well test technology in shale reservoir is still in the initial stage, the understanding of seepage characteristics is not deep enough, and the mature interpretation method has not been formed. Research and development of well test evaluation technology for fracturing effect, determination of fracture half length, fracture conductivity, formation permeability and formation pressure in the reconstruction area become important problems to be solved for fracturing design optimization and efficient development.

Aiming at the multi-stage fracturing technology of horizontal wells in the development process of shale reservoir, the wellhead pressure drop model of multi-stage volume fracturing and single-stage fracturing is established. The main technical contents include:

Study on the establishment of physical model and mathematical model of single-stage fracturing evaluation, study on the theoretical method, study on the solution method of mathematical model, and establish the pressure response characteristic curve.

By analyzing the influencing factors of pressure response characteristics, the main controlling factors of pressure curve shape characteristics were identified, and the analysis chart was established.

Research on conversion method of wellhead-bottomhole pressure, calculation method of wellbore vertical pipe flow under variable flow rate, variable density and variable viscosity; mathematical solution of complex vertical pipe flow equation; research on elimination method of pressure data fluctuation caused by water hammer based on filtering theory.

The influence of wellhead pressure accuracy and stop pump time on the corresponding characteristics of the model is analyzed.

Study on inversion of measured data and formation parameters method.

Based on the analysis and study of the construction data during fracturing, this project puts forward the well test analysis method of pump stop pressure drop, and forms the corresponding calculation module, so as to determine the fracture half length, fracture conductivity, formation permeability of reconstruction area and formation pressure of the fracturing well, and provides technical support for the fracturing effect evaluation in the process of shale oil volume fracturing development . This project not only provides a means of fracturing effect evaluation, but also provides a new method of using fracturing data to carry out formation evaluation, which has important application value. Moreover, there is no need to increase the test cost for this kind of data analysis, and it has immediate, accurate and low-cost technical and economic advantages.