Visual Experimental Study on Gradation Optimization of Two-Stage Gravel Packing Operation in Unconventional Reservoirs

Xingbang Meng,Tong Li,Minhui Qi,Zhongxiao Niu,Zhan Meng

doi:10.3390/en12081519

Abstract

During the development of unconventional reservoirs with high sand production rate and fine silt content such as heavy oil and hydrate reservoirs, silt sand blockage problem is a serious issue. A two-stage gravel-packing sand control technique is applied to solve the silt sand blockage now. However, traditional experiments on this technique could not obtain the dynamic distribution law of intrusive sand in the gravel pack. In this study, a new visualization experiment based on hydrodynamic similarity criterion for studying particle blockage in gravel packs was conducted. Real-time monitoring of sand particle migration in the gravel pack could be achieved. Also, the stable penetration depth and the distributing disciplinarian of invaded particles could be determined. The results show that when the gravel-to-sand median size ratio of gravel bed I is less than five, the sand bridge can be formed at the front end of the gravel pack. This could prevent sand from further intruding. As the grain size of gravel bed II is increased, the flow velocity is reduced. Thus, the sand invading into gravel bed II tends to settle at the interface. A large amount of sand intrusion can happen to gravel pack II when the pore filling front breaks through the gravel bed I.

Highlights

Sand production has become one of the main factors restricting the efficient development of unconventional reservoirs such as hydrate and heavy oil reservoirs
The selection criteria for gravel grain size of field operation mainly refer to the research of Saucier, which suggested a five to six times gravel-size field operation refer the experimental research of study, Saucier, suggested depth a fiveoftofour sixgroups times median grain sizemainly ratio
Particle migration and blockage in a two-stage gravel pack were obtained by the packing ratio on pore filling length and particle penetration depth was analyzed

Summary

Introduction

Sand production has become one of the main factors restricting the efficient development of unconventional reservoirs such as hydrate and heavy oil reservoirs. It is mainly reflected in the damage to the near region of the wellbore, artificial lift, and surface equipment. A high-rate gravel-packing sand control technique has been widely applied to solve this problem. This technique has high sand control efficiency, a long validity period, and alleviation of the productivity impairment caused by the sand blocking material [1,2,3]. When the gravel pack blockage occurred in tubing-casing annulus and perforation holes, the additional pressure in the gravel layer could be raised significantly

Methods

Results

Conclusion