Protocol for sand control screen design of production wells for clayey silt hydrate reservoirs: A case study

Abstract

The process of extracting natural gas from gas hydrate‐bearing sediments (GHBS) may yield significant sand influx due to the metastable nature of GHBS. Selecting appropriate sand control media is vital to addressing the challenges caused by excessive sand production. This study proposes a protocol called holding coarse expelling fine particles (HCEFP) for sand control design. The protocol aims to provide a new optimization method for screen mesh size selection for clayey silt hydrate reservoirs. Detailed optimizing procedures of proper candidate screen mesh sizes in hydrate exploitation well in clayey silt hydrate reservoirs are depicted based on the HCEFP. Then, the site W18, which is located in the Shenhu area of the northern South China Sea, is taken as an example to illustrate the optimization procedure for screen mesh size selection. The results reveal that complete solid retention via a standalone screen is rarely beneficial as high clay contents can adversely affect wellbore productivity due to excessive plugging. Screen aperture size selection for clayey silt hydrate wells should strike a balance between retaining coarser particles and avoiding screen blockage by the relatively fine particles. Furthermore, longitudinal heterogeneity of the PSDs also increases the difficulties associated with sand control design. Multistage sand control optimization is necessary in hydrate production wells. For Site W18, we recommend that the entire production interval can be divided into two subintervals for multistage sand control operations.

Numerical Investigation of the Gas Production Efficiency and Induced Geomechanical Responses in Marine Methane Hydrate-Bearing Sediments Exploited by Depressurization through Hydraulic Fractures

“…Larger production pressures, higher bottom-hole temperatures, larger horizontal stress differences, and higher permeabilities are deemed as causes for serious sand production . To improve the sand control efficacy, an optimization for the screen aperture size is needed as the screen should simultaneously retain coarse particles and avoid fine particle blockage . In addition, the dilatant behaviors under shearing in sediments with high hydrate saturations and low confining pressures can lead to tensile stresses.…”

“…24 To improve the sand control efficacy, an optimization for the screen aperture size is needed as the screen should simultaneously retain coarse particles and avoid fine particle blockage. 26 In addition, the dilatant behaviors under shearing in sediments with high hydrate saturations and low confining pressures can lead to tensile stresses. This is of particular significance as this phenomenon can contribute to unwanted hydrate dissociation in shallow methane hydrate reservoirs, and the geomechanical responses to methane hydrate exploitation can actually break the equilibrium in the hydrate-stable zones, 27,28 which may eventually evolve into uncontrolled gas release, sea floor subsidence, and submarine landslide.…”

Laboratory Study on Hydrate Production Using a Slow, Multistage Depressurization Strategy

“…Depressurization is also restricted by potential geohazards such as severe sand production [14][15][16], wellbore instability [17], and deformation of the sediment [18,19]. These potential geohazards are mainly controlled by the mechanical properties of HBS [20,21].…”

Study on the Influence of Sand Production on Seepage Capacity in Natural Gas Hydrate Reservoirs

“…Li et al and Cao et al believe that the secondary formation of hydrates and clay accumulation on the sand control medium are the key to clogging [14,15]. They suggested that a sand-control gravel sizing method called "Holding Coarse Expelling Fine Particles (HCEFP)" and artificial interference of downhole temperature was proposed to tackle the problems caused by possible screen clogging [16,17]. Uchida et al establish thermohydromechanically coupled formulation to research the features of sand production in gas hydrate-bearing sediments.…”