海上异常高温高压气藏产能评价方法

摘要

储层应力敏感性对气藏开发具有一定的影响，随着敏感性的增强，产能表现出明显降低的趋势。目前关于海上高温高压气藏考虑应力敏感性的产能研究较少，且海上气田受制于生产平台的限制，生产井一般为大斜度井，井斜产生拟表皮因数对产能也有较大影响。从渗流力学的基本理论出发，建立了综合考虑应力敏感性和高速非达西效应的大斜度井稳态产能方程，并对中海油某高温高压气藏进行了实例分析，验证了产能方程的可靠性。通过研究可知，高温高压气藏在开发初期应尽量降低采气速度，保持地层压力，防止产能过快下降。%The development of gas reservoirs is, in a way, affected by stress sensitivity of the reservoirs. With the increasing of sensitivity, the productivity follows obvious decline tendency. At present, stress sensitivity is less considered when the deliverability of highly deviated wells in offshore HTHP (high temperature/high pressure) gas reservoirs is studied. In offshore gas ifelds, production wells are mostly highly deviated wells due to the restriction of production platforms, and the deliverability is aslo signiifcantly affected by the pseudo-skin coefifcient induced by the well deviation. A steady-state deliverability equation of highly deviated wells, which takes stress sensitivity and high-velocity non-Darcy effect into consideration comprehensively, was developed based on the basic theories of seepage mechanics. Then, a ifeld case study was conducted on a HTHP gas reservoir of CNOOC to verify the reliability of the deliver-ability equation. It is concluded that at the early development stage of HTHP gas reservoirs, it is necessary to reduce gas production rate as much as possible to keep the reservoir pressure and avoid fast productivity decline.