Downhole Oil/Water Separator Development

Abstract

A feasibility study and subsequent equipment prototype design work completed by the Centre for Frontier Engineering Research have led to the development of some novel downhole oil/water separator systems for improving the economics and recovery of oil from cgnventional and heavy oil reservoirs. The basic concepts and driving forces behind the systems that have been developed a based on several ideas and technologies which were brought together with the objective of producing a lower cost altpmative for handling production and reinjection of water from maturing, high water oil ratio (WOR) reservoirs.These systems are currently in the prototype development phase in preparation for field testing. The downhole oil/water separation systems have the potential to achieve large, perhaps order of magnitude, savings in lifting costs through significant reductions in the volume of water that must be produced to surface. In most cases, these cost reductions would be accompanied by increased revenue. through reactiva-tion or increased production from wells that are currently shut-in or constrained by the limits of the current lifting system or sur-face facilities. Other potential benefits include reduced exposure to environmental liability from high volume water spills or cont-amination of fresh water aquifers. The main requirement for application of these systems is that a suitable water disposal zone be accessible from the producing wells. Introduction Numerous conventional oil wells, especially in North America and Southeast Asia, are becoming less econoi-nic due to high lift-ing costs and reduced recoveries. Much of the cost increase is ill managing the ever increasing volumes of water that must be lifted to surface, separated, treated, pipelined and reinjected back into the formations. Meanwhile ultimate recoveries are being eroded by shutting off production from specific reservoir zones through recompletions to reduce water inflow and bv the eventual early abandonment of wells which leaves itiuch of the original oil in place. The downhote separation project was initiated to help oper-ators keep wells on production longer, econ(iiiiically producin(, inore oil from existing mature reservoirs.

Study of Optimization Design on Oil-Water Separator of Injection-Production in the Same Well

“…The water content of the produced liquid of a high water cut oil well in Daqing oilfield is about 90%,viscosity is 2.9×10 -6 m 2 /s, daily handling capacity Q 0 is 80m 3 and 60m 3 respectively, Inner diameter of anchor pipe D is 38mm, the volume of anchor bowl V is 0.2L, the spacing of anchor bowl l is 0.045m, length of anchor pipe L is 30~80m. By means of above theory, the optimization software system is programmed by using VB6.0, the programming diagram is as shown in Figure 4.…”

“…(1) The proposed design scheme for the daily handling capacity of 80m 3 . Anchor pipe length 40m, which is divided into each section of 8m.…”

“…Two level orifice number: The orifice number of the first section 8m is 4; The orifice number of the second section 8m is 4; The orifice number of the third section 8m is 4; The orifice number of the fourth section 8m is 6; The orifice number of the fifth section 8m is 6. (2)The proposed design scheme for the daily handling capacity of 60m 3 .…”

“…At present, there are two main down hole oil-water separation types [3,4] : swirl separation technology [5] and gravity separation technology [6] . Using the similar separation principle of multi-cup uniform flux gas anchor, multi-cup uniform flux oil-water separator is designed, the problem of the bad separation of existing down hole centrifugal oil-water separator and impossible large-scale application in high water cut well can be solved.…”

A Review of Downhole Separation Technology

“…Several studies, including laboratory experiments, simulations, modeling, feasibility analyzes, and field applications have been carried out to demonstrate the DOWS technology. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] DOWS consists essentially of two systems: a separation system and a pumping/injection system. Two basic types of DOWS systems have been developed based on the separation system utilized.…”