Basin Scale Rock Mechanics: Field Observations of Sand Production

Abstract

Sand production is very common in the gas wells of the Adriatic Sea. Accurate field surveys have been conducted before and after sand production has occurred in wells where no sand control methods had been initially introduced. Unlike the numerous other papers dealing with sand production, this one describes the sand production observed in low permeability gas-bearing formations which include a significant amount of clays. The main parameters inducing sand production are identified and an empirical correlation is established which enables its prediction. Moreover, the influence of parameters such as depth, drawdown, depletion, gas rate, water gas ratio etc. on the occurrence of sand production is determined. The paper also reports the results of a sand flow test performed in a gas field situated in the surveyed area. Finally, these results are discussed in terms of geological history of the Northern Adriatic Basin.

An experimental and theoretical study of a partially saturated collapsible rock

“…8,9 Capillary effects were also considered as one of the explanations why water production does not seem to in¯uence sand production in the Adriatic Sea gas ®elds. 10 These shallow ®elds (1 000±1 400 m) are comprised of sandstones with practically no cementation between the grains. Their cohesion is simply the result of consolidation where grains are held together by capillary ®lms.…”

Rock mechanics characterization of deep formations: A technico-economical Overview

“…Furthermore, the pressure of continuing operations often makes it difficult to back analyse partial failures or successes thus corresponding to further waste of know how. In order to counteract such an "entropic effect", corporations have started systematic efforts of data concentration within databases, usually at the scale of a homogeneous geological unit such as a sedimentary basin [37][38][39]. The choice of such a scale corresponds to a double exigence [37]:…”

Optimized Perforation Tunnel Geometry, Density and Orientation To Control Sand Production

“…Marsala et al 15 and Moricca et al 16 presented a detailed case study of sand production in the Northern Adriatic Basin in Italy. The pay zones, which lie at depths of between 1000 m and 4500 m in this basin, are a sandy reservoir with low cohesion.…”

“…However, as soon as cohesion reaches a few MPa, sand production becomes increasingly improbable. The following empirical relationship between critical total drawdown (p CTD ) and rock cohesion (c) was obtained in this basin 16 :…”