Research On Casing Strings State Measurement System Under Water Injection

In the process of some oil extractions the casing pipes have distorted, the diameter reduction distortion of casing pipes gives rise to the problem of packer immediate and pipe string anchoring. And the downhole high-pressure separate layer strings may creep. It makes high-pressure separate water injection uneven, reduces oil extraction efficiency and increases the cost of production. In order to enhance productivity, it is necessary to get casing state parameters in the process of high-pressure water injection thoroughly. This way can help us design downhole tools and improve injecting water technology. It is researched mainly to the measuring technology of axial force of casing and creeping displacement under high temperature and high pressure condition. The measuring system of casing state tests simultaneously four parameters, which benefits to analyze the influence of temperature and pressure of liquid to axial force of casing and creeping displacement.It is much too expensive and unstable to transmit measure data and power by cables, because the system will go deep into casings the condition of which is so complex. The measure includes casings measuring, data storing and replaying in the up-ground processor. The system will measure the temperature and pressure of casings, axial force of casing and creeping displacement.There are two parts in the casings state measurement system, which are the casings measure and up-ground processor. The core of the casings measure is MB90F540/545 series MCU. The part of the casings measure accomplishes data collection, elementary data processing and data storing with the sensor module units. The core of the up-ground processor is the PC. It is connected to the casings measure MCU by interface circuits, by way of receiving, analyzing and replaying the measure data.The casing measurement system is packed in the short strings mechanism specially designed. The mechanism needs to be designed to withstand axial force and hydraulic pressure, and considered seal. The power of electronically circuit part is supplied by large capacity batteries which can resist high temperature. All sensors and electronic components must be steady and high temperature products and be passed through the test of temperature and performance, considered their volume and low-power loss. The system operates under saving energy mode by power administrated control-module, and data is stored in Flash ROM memory. The communication and data processing will be carried on after the short strings mechanism being got up to ground.The research of measure system on casing state while high-pressure separate layer water injection will help understand the real working condition of casing, providing direct data for downhole tools design. This will improve technology of layered water injection and enhance economic efficiency, so it is worth further studying.