产品展厅>>产品销售>>辰工试井系列软件>>间歇采油及提捞井试井分析

在低渗透(渗透率10md)及特低渗透(渗透率1md)油气藏中,油藏供油能力非常差,已不能连续开采。对这样油层的开发一般采用间歇方式采油,间歇采油使试井解释问题十分复杂:生产阶段或停产阶段,地层都不断地生产;在生产期间,井筒中的液面也在上升,地层的压降漏斗也在发生变化;产量和井底压力都是未知的。

辰工科技根据间抽及提捞采油的特点,建立了间歇采油的数学模型,提出了全压力历史拟合的试井分析方法。

对于开发井,由于生产时间很长,已无法得到原始的状态,因此测试时第一段应该是压力恢复,通过第一段的压力恢复可以大致反推第一段关井前的压降漏斗,依据这一压降漏斗计算压力历史。

在提捞井压力史计算中,由于提捞时间与恢复时间相比很小,在井筒压力计算中忽略提捞时间,而认为压力瞬间改变,即压力在提捞期间是阶梯变化,而停产期间压力变化按DST流动处理,可以自动计算回收量(当然用户也可以输入)。对于间抽采油由于存在地层流入到井筒的量与从井筒抽出的量不相等,所以需要输入流动达到稳定时的流量,同时也要确定稳定流动时间。

间歇采油试井在大庆油田得到应用,不仅得到了解释结果,而且根据解释结果优化了间抽及提捞采油的工作制度。

图1 提捞井曲线拟合及压力历史拟合图 图2 间抽井曲线拟合及压力历史拟合图

Products>>Products on Sale>>Chengong Well Testing Software Series>>Intermittent Oil Exploitation and Lifting Well Well Testing Analysis

In the low permeability (permeability 10md) and ultra-low permeability (permeability 1md) oil and gas reservoir, the oil supply capacity of the reservoir is very poor and cannot be continuously exploited. The development of such an oil layer generally adopts the intermittent oil production, and the intermittent oil production makes the well testing interpretation problem very complicated: the formation continuously produce oil during the production stage or the stop production stage; and during the production, the liquid level in the wellbore is also rising, and the pressure drop funnel of the formation is also changed; Both the production and the bottom hole pressure are unknown.

By Chengong science and technology, the mathematical model of intermittent oil production is set up according to the characteristics of the intermitted pumping and lifting oil production, and a well testing analysis method for full-pressure historical simulation is put forward.

For the development well, because of the long production time, the original state can not be obtained, so the first stage of the test should be pressure recovery. Through the pressure recovery of the first stage, the pressure drop funnel before the first stage shut-in can be inverse-derived approximately, and the pressure history can be calculated according to this pressure drop funnel.

In the calculation of the pressure history of the lifting well, because the lifting time is very small compared with the recovery time, the lifting time is ignored in the wellbore pressure calculation, and it is considered that the pressure changes instantly, that is, the pressure changes during the lifting period are step changes, and the pressure changes during the shutdown period can be considered as DST flow, it can calculate the recovery automatically (of course, the user can also input). For inter-pumping oil exploitation, because the amount of formation flowing into the wellbore is not equal to the amount that extracted from the wellbore, it is necessary to input the flowrate when the flow reaches stable, meanwhile, the stable flow time should be confirmed.

The application of intermit well testing in Daqing Oil Field is utilized. Not only the result of interpretation is obtained, but also the working system of intermitted pumping and lifting oil production is optimized according to the interpretation results.

Figure1: Curve and pressure history simulation chart of lifting well Figure2: Curve and pressure history simulation chart of intermitted pumping well