Due to reduced availability of high quality reservoirs, more wells require stimulation. The current default method for stimulation is hydraulic fracturing, using either proppant or acid to keep the fracture open. In many environments, Proppant or Acid Fracturing is a good solution to increase productivity. Some of the unresolved challenges with fracture stimulation are reservoir related such as the uncertainty about whether the fracture will grow through different reservoir layers, potentially contacting unwanted water. Operational challenges are environmental, cost, operational complexity and availability of equipment and competent personnel. Onshore fracturing experience can build on the learning of hundreds of wells to optimize the fracture stimulation process, but this is not possible in an offshore environment.
A new completion based stimulation solution is developed to be simple and efficient without environmental impact and with significantly lower cost than current solutions. Several reservoirs have been simulated to investigate the long term production and recovery using the method. The relatively new well geometries require further understanding to apply the technology. A study on offshore well cost has been made.
New completion techniques improving recovery, production rates and reducing cost and complexity are always looked for in the oil and gas industry. This paper is presenting a new concept where 100's of small level 5 laterals can be drilled simultaneously into the formation around a main wellbore. This paper presents the main concept as well as some preliminary results from qualifying the system for service in a high porosity very weak chalk reservoir. The qualification of the system is addressing three main aspects, the ability to jet a 12 meter long and 5–10mm diameter lateral, the ability to produce in high porosity weak chalk without loss of production, and simulation of production that is at least as good as or better than existing technologies like propped fractured horizontal wells, acid fractured horizontal wells and different types of openhole completions with and without liners. The experiments indicate that the system is able to achieve the results we are looking for.
Introduction
Increasing productivity in conventional and tight reservoirs is commonly achieved by stimulation operations. Environmental and economic effects require complex logistical setups and often demand experimentation to achieve good productivity.
Multilateral technology is an alternative to stimulation, and jetting laterals with acid or non- reactive fluids have become an increasingly employed alternative to stimulation in some fields. The most common systems utilize coiled tubing or hoses as the fluids deployment conduit (Rae et al, Cirigliano et al). Some systems can be employed in open hole, but if the motherbore is lined, any motherbore liner needs to be penetrated by jetting or milling holes. The jetting systems require intervention and only one lateral can be jetted at any time.
The development of the Acid Needle jetting system started with the premise of making multiple small diameter laterals simultaneously to simplify operations and allow large numbers of laterals increasing reservoir contact. Intuitively a large number of laterals spaced out in the liner would create predictable and evenly distributed flow patterns increasing recovery of hydrocarbons significantly. The design parameters of the system were:Placement of laterals should be predictable and controlled by spacing out liner completion itemsIt must not require intervention and the only operation must be pumping small volumes of commonly available fluids from surfaceLaterals should be uncemented, connected to the motherbore, lined and enable formation solids control (sand screen)Not require specialist service personnel on rigsiteBe extendable to cover a broad range of wells and formationsBe no restriction for intervention
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