Investigation Of Circuit Of Dual-driving MicroSFL, Microelectrode And Caliper Combination Logging Tools

Up to now, the lateral logging and microlateral logging tools have been replaced by microSFL (microsphere focusing logging), microelectrode logging tools which are the main methods to get the formation resistivity. The used logging tools in Daqing Wireline Logging Company are data transmission joint, gamma-ray logging, continuous inclinometer, microSFL, microelectrode logging, caliper, sonic logging, 3-lateral logging, lateral logging, and so on. These logging tools can be combined because they all have the digital communication interface. Using the interface, the logging tools receive the order from the surface system and then the logging process can be controlled. At present, the main investigations are concerned on how to use the interfaces and to develop the logging tools. In order to enhance the logging quality, the circuit of MicroSFL, Microelectrode and caliper combination logging tools was developed based on the digital logging system and communication interface. In Daqing Oil Field, the microSFL, microelectrode logging tools and caliper should be used in the formation evaluation. Combining of these logging tools has several advantages, such as the length and the weight of the tools can be decreased, the data of these logging tools can be obtained simultaneously and it is favorable to enhance the efficiency.In this paper, factors that affect the performances and security of the microSFL, microelectrode logging tool and caliper were investigated, as shown as follows,1) Contact pad wear and the logging security,2) Current supply of microelectrode logging tool.3) The accuracy of caliper.The main researches are as follows.1) The field test of the microSFL, microelectrode logging tool and caliper, 2) With the RS485 BUS, these logging tools can be combined using the PCM9801 data transmission system. The logging tools can be calibrated and pushed under the orders from the surface logging system.3) With the dual-driving mode, when the power supply of the logging tools are disconnected, the contact pad and caliper can be pushed with line 1 and 3 of the wire line; when the power supply of the logging tools are connected, the contact pad and caliper can be pulled under the order from the logging system. So the wear of pad can be decreased and the logging efficiency and security can be improved.4) For the microSFL, the value of the current supply was controlled to enlarge the measurement range.5) For the microelectrode logging tool, the sinusoidal current supply was used to decrease the noise and improve the precision.6) For the caliper, the four-line measurement was used to decrease the effect of the line resistivity and contact resistivity on the results.The microSFL, microelectrode logging tool and caliper combination logging tool were developed based on the above researches. The field tests of the combination tool show that1) The dual-driving mode is effective and reliable. After the measurement of the destination formations, the pad and caliper can be pulled under the order from the surface logging system when the logging curves are record. The wear rate decreases more than 80% and the rate of risk which caused by the pad stuck also decreases more than 80%.2) Since the sinusoidal current supply was used in the microelectrode logging tool, the effects of the microelectrode supply on the signal of other logging tools (such as microSFL) were decreased.3) The four-line measurement mode in the caliper is practical and effective. When the sum of the line resistivity and contact resistivity is 5 ohm, the precision can be increased 2%.Following the research, not only the microSFL, microelectrode logging tool and caliper can be combined successfully, but also a thinking, i.e., practical experience based on the innovation, was obtained to develop and supplement the application of the theory and definition of well logging. The purpose of the practice is to verify and optimize the theory. How to transfer the theoretic results into efficient industrial production capability is my investigation motive and direction.