Abstract

Oil companies in Canada are aggressively developing heavy oil reservoirs and are encountering many new problems in the development of this extensive resource. One major problem that has been experienced is the excessive production of formation sand. Most often, the oil companies have been attempting to handle the formation sand by modifying the pumps and surface equipment to handle the sand rather than to control it downhole. Viscous gravelpacking has recently been utilized as the downhole sand control technique applied in the heavy oil reservoirs in the central section of the Alberta Saskatchewan border area (Figure 1). Procedures were developed using properly-sized gravels, wire wrapped screens, liners designed to accommodate unforeseen future work overs and modified gravel pack tools. Treated and conditioned high viscosity fluids with high gravel to fluid ratios were enjoyed for grave1 placemen tat reduced pump rates. The sand control procedures applied to the Canadian wells have effectively stopped the production of the formation sand. The downtime due to sand related problems has dropped, and the overall production rate has been maintained. Because the wells have been producing essentially sand free, bailing operations or pump replacement associated with formation sand damage have been unnecessary.

Introduction

As the search for oil and gas leads producers to attempt development of heavy oil sands and shallow gas. sands in Canada, problems with formationsand production have been regularly encountered for the past several years. When a well is "sanded up," the loss in production is compounded by workover rig expenses, replacement of damaged downhole and surface equipment and the cleaning of settled sand From surface tanks and flow lines. To control the production of formation sand, three operators in Canada have tried a new approach to gravel packing. These procedures have been used in heavy oil sands by two of the operators and in a shallow gas sand by a third.

Each of the three operators has been faced with slightly different well conditions and formation sand problems. Company A produces 17 °API crude Without thermal stimulation in the Neilburg Poolnear Lloydminster, Saskatchewan. Company B, located near Grande Centre, Alberta, must use steam stimulation to enable production of 14 ° API crude. The shallow gas sand production of Company C is from the water-sensitive Milk River Formation near Brooks, Alberta, in the Lake Newell Field.

PRODUCTION PROBLEMS

Wells managed by Company A in the Neilburg Pool produced from the McCaren Sand Formation with average intervals from 573 m to 576 m (1,891 ft to 1,883 ft) Most of the wells produced some formation sand, and as a result, Company A has had to modify downhole pumps, surface equipment and tank batteries to cope with the formation sand production. However, in two severe cases, sand production problems forced Company A to employ gravel packing.

The severity of the problem is demonstrated in the production history of these two wells.

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