Scaled experiments of flow near, and inside, a horizontal well in steamflooding

Mathematical equations were formulated to model flow in the vicinity of, and inside, a horizontal wellbore. Inspectional analysis was next used to isolate and identify scaling groups from the dimensionless form of these equations. Two different sets of scaling criteria were developed: one for the flow process in the reservoir, and the other for flow inside the horizontal well. The scaling criteria were then used to design and construct linear, high-pressure scaled physical models, as well as to determine the operating conditions for a series of steam injection experiments, which were carried out in the physical models.;The experiments were intended to determine primarily the effects of wellbore geometry and well completion on the performance of various steam injection recovery processes. Apparatus was set up to inject continuously superheated steam at a constant steam injection pressure into a model reservoir of tightly packed and compressed Ottawa silica sand, and saturated with water and FAXAM-100 oil. A variety of horizontal well designs and perforated casings, along with different combinations of injector and producer, were tested. Their performance, based upon various oil recovery performance indicators, was compared to determine the relative merits and potential effectiveness of variable-and constant-diameter horizontal wells--both with and without casing, vertical producers, and horizontal injectors.;Based on the experimental results, it is concluded that first, variable diameter horizontal wells can reduce the axial well pressure gradients, provide a higher fluid production rate, recover more oil, and achieve higher thermal efficiency than their constant-diameter counterparts. Second, perforated casing can reduce the overall recovery performance (i.e. lower fluid production rate, oil recovery, and thermal efficiency) of a horizontal producer by impeding the flow of reservoir fluids into the well.