Factors Affecting Horizontal Well Gravel Pack Efficiency

Abstract

Four major factors affecting horizontal well gravel pack were studied using a 3D simulator developed for horizontal well gravel packing. The factors included settling effect, gravel concentration, injection rate and carrier fluid viscosity. Three actual field horizontal well gravel pack jobs obtained from the literature were performed using the simulator to study these factors. The effect of carrier fluid viscosity on gravel pack efficiency was studied by varying the viscosity between 1 and 51 cP, injection rate between 0.159 and 0.636 m3/min and gravel concentration between 0.50 and 4.0 pound mass per gallon. Simulation results demonstrate the validity of the solution routine and the capability of the simulator, because the results were in agreement with the field results. The predicted pack efficiency for cases that considered settling effect are consistently higher than the cases without settling effect. The study also showed that the settling factor decreases with increasing gravel concentration and injection rate. Introduction Several authors have investigated the factors affecting gravel transportation and placement towards achieving an effective gravel pack. Gruesbeck et al.(1) performed experiments to measure pack efficiency as a function of screen parameter, fluid and gravel properties, completion configuration and angle of inclination of the wellbore. They concluded that packing efficiency increases with lower gravel concentration, lower gravel density, higher flow rate and increasing resistance to fluid flow in the tailpipe/screen annulus. Hodge(2) substantiated Gruesbeck et al.'s work by determining the accuracy of the predicted equilibrium bank height. Elson et al.(3) reported a study conducted to define optimum gravel pack procedures and completion design factors for high angle wells. Results of the study showed that high viscosity carrier fluids with high gravel concentration provide good gravel transport, but are unsuitable in wells with angles of 80 º from vertical. Skaggs(4) presented the results of a large-scale vertical wellbore model he used to study gravel transport through perforations during a high-density squeeze gravel packing operation. He concluded that the transport efficiency through perforations increases with increased fluid viscosity, gravel concentration and annular velocity. Winterfeld and Schroeder(5) developed a finite element numerical simulator and used it with a full-scale wellbore model to study gravel placement in perforations and annulus. Their model was based on mass and momentum conservation equations, as well as those for vertical wells. Peden et al.(6) developed some mathematical design models for predicting the optimum combination ofrequired design parameters, such as tailpipe diameter, slurry flow rate and gravel concentration, for an optimum packing efficiency. These models were based on extensive experimental study of factors affecting packing efficiency and dimensional analysis of obtained data. In 1988, Wahlmeier and Andrews(7) improved on the earlier works of Gruesbeck et al. and Peden et al. by developing a pseudo-three-dimensional mathematical model suitable for designing and evaluating gravel pack treatments. Shryock(8) worked on a full-scale deviated model and had similar conclusions with earlier works.

Overview of Methods for Enhanced Oil Recovery from Conventional and Unconventional Reservoirs

“…To determine the yielding zones and areas exposed by the horizontal wells, geophysical studies are carried out, according to which the yielding intervals are distinguished. The effect of anisotropy is considered in [115,136].…”

Research on Water Finding Methods for Horizontal Wells

“…Since the 1990s, the research and development on horizontal well development technology has developed very rapidly [1], and it has been widely applied in the development of oil and gas reservoirs such as bottom-side water, natural fracture development, thin layer, low permeability, unconventional, and conventional thick oil, which has become a new type of development method, and it is an important means to change the traditional open method. In the development history of horizontal well technology, it has mainly experienced five technological changes: in 1920-1930, the breakthrough of reflection seismic technology promoted the progress of horizontal well development, and the production increased from 1×10 8 t to 2×10 8 t; in 1960-1970, with the development of oil production theory, injection drilling, water injection development, plate tectonics and other technologies [2], it promoted the production of horizontal wells from 10×10 8 t to 20×10 8 t. 108t to 20×10 8 t; in 1980-1990, relying on the development of basin simulation, secondary oil recovery technology, 3D seismic, and horizontal drilling, horizontal well production was maintained at around 30×10 8 t; in 2000-2015, unification was shown in the technologies of ultra-high-density data acquisition, drilling logging with drilling, horizontal well fracturing in sections, and rotary-guided drilling, with the production stepping up to 40×10 8 t ; in 2020-2035, it will be represented by new technologies such as intelligent drilling, intelligent oilfield, in-situ reforming, nano oil drive, etc., which may drive the production to cross a new high [3].…”

Numerical Simulation of Pulsed Gravel Packing Completion in Horizontal Wells

“…Based on the solid-liquid two-phase flow theory, Pu [21] established an intelligent calculation system for gravel packing in horizontal wells, which considered formation leakage. Ojo et al [22,23] established a three-dimensional mathematical model of gravel packing in horizontal wells under the influence of multiple factors and predicted the balanced height of sand bed during gravel packing process in horizontal wells. When Dong et al [24][25][26] conducted a numerical simulation study on the gravel packing process in horizontal wells, they took into account the influences of sand-carrying fluid filtration to the formation and fluid mass exchange between wellbore annulus and scrubber annulus on gravel packing.…”